Simplified procedures to treatperiodontal intraosseous defectsin esthetic areasLEONARDO TROMBELLI, ANNA SIMONELLI , LUIGI MINENNA,RENATA VECCHIATINI & ROBERTO FARINA
Intraosseous defects are defined by the apical loca-tion of the base of the pocket with respect to theresidual alveolar crest (31). Clinically and radiograph-ically, 18–51% of subjects present at least oneintraosseous defect (7, 22, 30, 33, 41, 42, 54, 60).Intraosseous defects are at high risk of furtherprogression and may lead to tooth loss if leftuntreated (32). The treatment of periodontitis, whichalso encompasses intraosseous defects, is based onremoval of supra- and subgingival biofilm, achievedby patient-performed oral hygiene associated withprofessional nonsurgical periodontal debridement. Asintraosseous defects may be associated with persistentdeep pockets and bleeding following conventionalnonsurgical treatment, these lesions are frequentlyconsidered as sites requiring surgical therapy (17).Historically, the ‘classical’ surgical approaches used toaccess and treat periodontal intraosseous defects werebased on flap designs characterized by either minimaltissue resection (21, 35) or total preservation of inter-dental tissues, such as the papilla-preservation tech-nique (43) and its variants (2–4, 15, 26, 45). All theseflap designs are based on the elevation of a doublemucoperiosteal flap involving both buccal and oralaspects (47).
The term ‘simplify’ means the act of making some-thing less complex. Its etymology originates from theMedieval Latin verb simplificare which, in turn,derives from the terms simplex (simple) and facere(make). We define a procedure as ‘simplified’ whenit provides more favorable conditions for eitherthe patient or the clinical operator. Although theterms ‘simplification’ and ‘minimal invasiveness’ mayappear as synonyms when referring to periodontaltreatment, in our perspective ‘simplification’ implies
a substantially different concept. For the operator, asimplified procedure should: (i) require limited surgi-cal equipment; (ii) be characterized by a steep andshort learning curve; and (iii) limit the need for theuse of additional treatments/devices (through maxi-mizing the inherent healing potential of the treatedlesion). For the patient, a simplified procedure shouldhave reduced impact on: (i) post-treatment dailyactivities; (ii) post-treatment pain and discomfort(also reducing the required compliance for post-treat-ment regimens); and (iii) pre-existing esthetics. Forboth patient and operator, a simplified procedureshould reduce: (i) chair-side time needed for treat-ment administration and follow-up visits; and (ii)treatment costs.
Nonsurgical therapy as a solo treatment alwaysrepresents a ‘simplified’ procedure, particularly whencompared with surgical approaches. Among the sur-gical options available, ‘simplified’ surgical proce-dures, as recently proposed, will be thoroughlyrevised in this chapter of Periodontology 2000. Theseprocedures share a common technical aspect, namelythe elevation of a single flap on the buccal or oralaspect, leaving the tissues on the opposite side intact(see the ‘Technical aspects’ section for details). All thesimplified treatments (either nonsurgical or surgical)described here were originally designed and proposedas minimally invasive approaches for periodontaltreatment, mainly aimed at minimizing tissue traumaand consequently intra- and postoperative morbidity(16). In this respect, it will be shown that the minimalinvasiveness of such procedures may be partly a resultof the simplification of the treatment approaches. Wedescribe here the technical aspects and the effect onclinical parameters and patient-centered outcomes of
Printed in Singapore. All rights reserved PERIODONTOLOGY 2000
the simplified procedures for the treatment ofperiodontal intraosseous defects, specifically whenlocated in the esthetic area. Particular emphasis is onstudies comparing simplified and classical proceduresas well as the application of simplified surgical proce-dures in addition to regenerative devices.
Simplified procedures for thetreatment of periodontalintraosseous defects: technicalaspects
Nonsurgical procedures
Table 1 summarizes the studies on nonsurgical ther-apy for the treatment of intraosseous defects. Allstudies incorporated a thorough subgingival instru-mentation performed with manual instruments,either alone (20, 36) or in combination with mechani-cal instruments (19, 28, 29, 37). Recently, minimallyinvasive nonsurgical periodontal therapy has beenintroduced as a concept aimed at obtaining extensivesubgingival debridement with minimal tissue trauma(37). Minimally invasive nonsurgical periodontal ther-apy is based on the following principles: (i) thoroughdebridement of the root surface to the bottom ofthe periodontal pocket, avoiding root planing andgingival curettage; (ii) use of a magnification system;(iii) prevalent use of an ultrasonic device with speci-fic thin tips, complemented by Gracey minicurettes;and (iv) caution to preserve the integrity of softtissues.
Surgical procedures
In 2007, the first simplified surgical procedure wasproposed (48). This procedure, which was defined asa single flap approach, is based on the elevation of aflap on one aspect only (buccal or oral, depending onthe extension/morphology of the lesion), thus pre-serving the integrity of the interdental soft tissue(Fig. 1). The elevation of a single flap to access theintraosseous defect may pose several clinical advan-tages. First, it may facilitate flap repositioning andsuturing; the flap can be easily stabilized to the unde-tached papilla, thus optimizing wound closure forprimary intention healing. Moreover, by leaving agreat volume of supracrestal soft tissues intact, accel-erated re-establishment of the local vascular supplymay occur. Wound stabilization and preservation ofan intact interdental papilla may also contribute to
enhanced preservation of the pre-existing gingivalesthetics.
A prerequisite to apply the single flap approachprinciples is that the morphology of the defect iscompatible with thorough root/defect debridementwhen accessed by either the buccal or oral side only.Whenever the bucco-oral extension of the defect pre-vents successful removal of the oral biofilm from theroot surface as well as the complete degranulation ofthe intraosseous component of the defect, conven-tional double-flap approaches should be performed.However, data derived from the distribution ofintraosseous defects according to the bone morphol-ogy (44, 54), combined with observation from aprospective trial (6), seem to suggest that a single-flap(usually buccal) access to intraosseous defects maybe feasible in a relevant proportion of surgically trea-ted defects.
The single flap approach is a simplified surgicalapproach that is used to access periodontal intraoss-eous defects (48, 49) (Fig. 1). The basic underlyingprinciple of the single flap approach consists of theelevation of a limited mucoperiosteal flap to allowaccess to the defect from either the buccal or oralaspect only, depending on the main buccal/oralextension of the lesion (as diagnosed by preoperativebone sounding and periapical radiographs), preserv-ing the integrity of the interproximal supracrestal gin-gival tissues. A single flap approach mainly consists ofan envelope flap. Sulcular incisions are performed onthe buccal or oral side (for defects with a prevalentextension on the buccal or oral side, respectively) fol-lowing the gingival margin of the teeth included inthe surgical area. The mesiodistal extension of theflap is kept as limited as possible while ensuringproper access for defect debridement (as well as posi-tioning/application of a regenerative device, if indi-cated). Therefore, priority, in terms of flap extension,is given to provide adequate surgical access, some-times extending the incision to involve the papillae ofadjacent teeth in order to limit the use of verticalreleasing incisions. In the interproximal area (i.e. atthe level of the interdental papilla) overlying theintraosseous defect, an oblique or horizontal butt-joint incision is made following the profile of theunderlying bone crest. The distance between the tipof the papilla and the apicocoronal level of the inter-dental incision is based on the apicocoronal dimen-sion of the supracrestal soft tissues. Preoperatively,probing measurements are carefully performed toassess the horizontal component of the bone loss andtherefore the apicocoronal dimension of the softtissues overlying the bone crest. The greater the
Trombelli et al.
94
Tab
le1.
Clin
ical
studiesev
aluatingtheeffectiven
essofn
on-surgical
therap
yin
thetrea
tmen
tofintrao
sseo
usdefects
Study
Exp
erim
ental
design
Number
ofdefects
Rad
iograp
hic
dep
thof
intrao
sseo
us
componen
t
Baseline
pro
bing
dep
th(m
ean,
mm)
Treatmen
tap
pro
ach
Loca
liza
tionof
intrao
sseo
usdefects
Follow-u
p
(months)
Clinical
outcomes
Rad
iograp
hic
outcomes
Patient-centeredoutcomes
Clinical
attach
men
tleve
l
Pro
bing
dep
th
Gingiva
l
recession
Isidor
etal.1
985
(20)
Split-m
outh,
prosp
ective
clinical
trial
13≥15
%ofrootlength
7.6
Rootplaningwith
man
ual
instrumen
ts
Lateralincisors,c
anines,
premolars
12Mea
nga
in,1
.6mm
Red
ucedto
4.2mm
Mea
n
increa
se,
1.8mm
Mea
nga
inin
boneheigh
t:0.9%
(noalterationin
50%
ofd
efects;
chan
geco
mprised
betwee
n�1
0%
and+10
%in
the
other
50%
ofd
efects)
Notav
ailable
Ren
vert
etal.1
985
(36)
Split-m
outh,
prosp
ective
clinical
trial
25Notav
ailable
6.7
Rootplaningwith
man
ual
instrumen
ts
Alltooth
types
6Mea
nga
in,0
.8mm
Red
ucedto
5.2mm
Mea
n
increa
se,
0.8mm
Notav
ailable
Notav
ailable
Hwan
g
etal.
2008
(19)
Caseseries
39(sites)
≥3mm
6.57
Scalingan
drootplaning
usingmechan
ical
and
man
ual
instrumen
ts
Alltooth
types
6Notav
ailable
Notav
ailable
Notav
ailable
Increa
sein
radiograp
hic
den
sity
in83
.3%
oftheregions
analyzed
Notav
ailable
Nibali
etal.
2011
(29)
Retrosp
ective
study
126
Mea
n,3
.8mm
6.5
Scalingan
drootplaning
usingmechan
ical
and
man
ual
instrumen
ts
with/w
ithoutsystem
ic
orloca
lantibiotics
Alltooth
types
Ran
ge,
12–1
8
Mea
nga
in,1
.42–
1.50
mm
Mea
n
reduction,
2.24
–
2.29
mm
Mea
n
increa
se,0
.5
–0.7
mm
Vertica
ldefect
dep
threduced
to3.08
mm
(persisten
t
radiograp
hic
defectdep
th≥2.0
mm
in71
%of
defects)
Notav
ailable
Ribeiro
etal.2
011
(37)
Parallel-arm
randomized
controlle
d
trial
13patients
with≥1
defect
≥4mm
6.35
Scalingan
drootplaning
withminicurettes
and
anultrasonic
dev
ice
withsp
ecificthin
tips
under
anoperating
microscope
(minim
ally-inva
sive
nonsu
rgical
periodontaltherap
y)
Single-rootedteeth
6Mea
nga
in,
2.56
mm
Mea
n
reduction,
3.13
mm
Mea
n
increa
se,
0.45
mm
Notav
ailable
Low
extentofd
isco
mfort,root
hyp
ersensitivity
anded
ema
duringthefirstpost-therap
y
wee
k
Nohem
atoma,
highfeve
ror
interferen
cewithdaily
activities
Mea
nnumber
ofan
alge
sic
med
ications:0.31
92.30%
ofp
atients
very
satisfi
edat
6months
14patients
with≥1
defect
≥4mm
7.07
Minim
ally
inva
sive
surgical
tech
nique(4)
Single-rootedteeth
6Mea
nga
in,
2.85
mm
Mea
n
reduction,
3.51
mm
Mea
n
increa
se,
0.48
mm
Notav
ailable
Low
extentofd
isco
mfort,root
hyp
ersensitivity
anded
ema
duringthefirstpost-therap
ywee
k
Nohem
atoma,
highfeve
ror
interferen
cewithdaily
activities
Mea
nnumber
ofan
alge
sic
med
ications,0.40
92.85%
ofp
atients
very
satisfi
edat
6months
Simplified procedures for intraosseous defects
95
distance from the tip of the papilla to the underlyingbone crest, the more apical (i.e. close to the base ofthe papilla) the incision in the interdental area. Thisis undertaken to provide an adequate amount ofuntouched supracrestal soft tissue connected to theundetached papilla to ensure flap adaptation andsuturing as well as to warrant proper access to theintraosseous defect for debridement and, whenneeded, graft/membrane positioning. The defect isapproached by elevating a flap only on the buccal ororal side and leaving the opposite portion of theinterdental supracrestal soft tissues undetached. Thefull-thickness elevation of the marginal portion ofthe flap should be performed using a microsurgicalperiosteal elevator. Partial-thickness dissection, ifneeded, must be limited to the apical portion of theflap to ensure flap replacement and suturing withouttension. Once root and defect debridement has beencompleted, a horizontal internal mattress suture isplaced coronal to the mucogingival junction betweenthe flap and the base of the undetached papilla inorder to provide the flap repositioning. Then, a verti-cal or horizontal internal mattress suture (or an inter-rupted suture) is placed between the most coronalportion of the flap and the most coronal portion ofthe intact papilla to ensure primary closure. Sutureremoval is performed 14 days after surgery.
More recently, other authors proposed variants ofthe single flap approach in which only a single buccalflap is raised to access the intraosseous defect (1, 5,63). In 2008, Checchi et al. (1) modified the originaltechnique of the single flap approach by coronallyadvancing the flap, with the intention to minimizethe esthetic impairment related to the surgical proce-dure and optimize soft-tissue closure at the incisionmargin. This technique was named the coronallypositioned single flap approach. In order to coronallyadvance and stabilize the flap, split-thickness prepa-ration of the tissues in the apical portion of the flapand de-epithelization of the interdental papillae wererecommended. The modified minimally invasive sur-gical technique was proposed in 2009 (5). Substantialoverlap exists between the modified minimally inva-sive surgical technique and the buccal single-flapapproach, including aspects related to the interdentalflap incision and flap management. However, in themodified minimally invasive surgical technique themesiodistal extension of the incision is kept at a mini-mum (ideally, within the mid-buccal area of theinvolved teeth) to allow reflection of a triangular buc-cal flap. A microblade is used to cut through the inter-dental tissues, with an inclination suitable tointercept the buccal side of the lingual bone crest, asT
able
1.(Con
tinued
)
Study
Exp
erim
ental
design
Number
ofdefects
Rad
iograp
hic
dep
thof
intrao
sseo
us
componen
t
Baseline
pro
bing
dep
th(m
ean,
mm)
Treatmen
tap
pro
ach
Loca
liza
tionof
intrao
sseo
usdefects
Follow-u
p
(months)
Clinical
outcomes
Rad
iograp
hic
outcomes
Patient-centeredoutcomes
Clinical
attach
men
tleve
l
Pro
bing
dep
th
Gingiva
l
recession
Nibali
etal.2
015
(28)
Retrosp
ective
study
35≥3mm
mea
n,6
.7mm
7.8(atdee
pest
site)
Minim
ally
inva
sive
nonsu
rgical
periodontaltherap
y
(37)
Alltooth
types
12Mea
nga
in,2
.8mm
Mea
n
reduction,
3.1mm
Increa
sed
from
0.6mm
to0.8mm
Red
uctionof
intrao
sseo
us
componen
t,
2.93
mm
Supraosseo
us
componen
t
increa
sedfrom
2.1mm
to
2.6mm
Notav
ailable
Trombelli et al.
96
A B C
J K L
D E F
G H I
Fig. 1. Operative steps to perform a surgical access accord-ing to the principles of the single flap approach. (A) Pre-operative probing following non-surgical treatment of adefect located at the mesio-buccal aspect of a maxillary lat-eral incisor. (B) The defect has a minimal to null extensionon the palatal aspect, as detected by pre-operative probing.(C) Pre-operative periapical radiograph. (D) An oblique orhorizontal, butt-joint incision is performed at the level ofthe interdental papilla. The incision is extended intrasulcu-larly at the adjacent teeth. (E) Buccal flap elevation with amicrosurgical periosteal elevator. The oral portion of theinterdental supra-crestal soft tissues is left undetached. (F)
In this case, the intraosseous component of the defect(depth, 5 mm) is left filled with a blood clot only. (G) Firsthorizontal internal mattress suture at the base of the papilla.(H) Second internal mattress suture at the most coronalportion of the papilla. (I) Complete wound closure andabsence of fibrin line in the interproximal area (equivalentto an early healing index of 1, as proposed by Wachtel et al.(55)) are observed at suture removal (2-week post-surgery).(J) Healing at 6 months after surgery. (K, L) Clinical andradiographic aspect at 3 years following surgery (re-adaptedfrom Trombelli et al. (51)). This figure is reproduced withpermission from the American Academy of Periodontology.
Simplified procedures for intraosseous defects
97
close as possible to its coronal edge, to isolate thegranulation tissue filling the intraosseous componentof the defect from the supracrestal papillary tissues.Wound closure is obtained with a single, modifiedinternal mattress suture positioned at the defect-associated interdental area. More recently, Zucchelliet al. (63) combined the single flap approach with aconnective tissue graft in order to treat challengingintraosseous defects associated with Miller’s Class IVgingival recessions. To ensure sufficient graft cover-age, the flap was coronally advanced and fixed to thede-epithelialized interdental papillae. The entirety ofthe interdental supracrestal soft tissue is pushed in apalatal direction until the tip of the interdental papillais shifted in the most coronal position in order tofacilitate flap stabilization in the area overlying theintraosseous defect. No attempt is made to elevate anoral flap.
Simplified procedures for thetreatment of periodontalintraosseous defects: effect onclinical parameters and patient-centered outcomes
Nonsurgical procedures
Clinical parameters
Data on the effectiveness of nonsurgical therapy inthe treatment of intraosseous defects are reported inTable 1. In general, defects showing a probing depthof < 7 mm and a radiographic depth of the angularcomponent of ≥ 2 mm were included. Althoughimprovements in clinical and radiographic parame-ters were reported at 6–18 months of follow-up, sub-stantial heterogeneity in treatment outcomes wasobserved among studies. Some studies reported amean gain in clinical attachment level of 0.8–1.6 mm,an increase in bone height of 0.9% and a mean resid-ual probing depth of 4.2–5.2 mm (20, 36). In contrast,when nonsurgical treatment was administeredaccording to minimally invasive nonsurgical peri-odontal therapy, greater clinical improvements wereobserved (28, 37). At 6 months, a clinical attachmentlevel gain of 2.56 mm and a probing depth reductionof 3.13 were reported by Ribeiro et al. (37). Similarly,an average reduction in the radiographic verticaldefect depth of 2.93 mm, accompanied by a clinicalattachment level gain of 2.8 mm and a probing depthreduction of 3.12 mm, was observed by Nibali et al.(28) at 12 months following treatment. The
magnitude of postoperative increase in gingival reces-sion following nonsurgical treatment of intraosseousdefects also shows variations among studies(Table 1). While some studies report a gingival reces-sion increase of 0.8–1.8 mm (20, 36), a more limitedpost-treatment recession has been observed in recenttrials. In particular, a mean gingival recessionincrease of 0.2–0.45 mm was reported following mini-mally invasive nonsurgical periodontal therapy (28,37). In one arm of a randomized controlled trial (37),the mean chair-time (as assessed from injection oflocal anesthesia to completion of the professionalinstrumentation of the tooth surfaces) for minimallyinvasive nonsurgical periodontal therapy was29.15 � 4.30 min.
Patient-centered outcomes
Data stemming from one arm of a randomized con-trolled trial (37), in which nonsurgical treatment ofintraosseous defects was based on minimally invasivenonsurgical periodontal therapy principles, indicated:� Low levels of pain and discomfort following the
procedure. Also, the mean dose of analgesic medi-cation consumed was low (fewer than one anal-gesic tablet per patient).
� A negligible extent of discomfort, root hypersensi-tivity and edema during the first week followingtreatment. In addition, no patients reported inter-ference with daily activities during the post-treat-ment period.
� At 6 months, patient judgement on treatment out-come ranged from ‘very satisfied’ (92.30%) to ‘sat-isfied’ (7.7%).
Surgical procedures
Clinical parameters
Data from studies evaluating the effectiveness of sim-plified surgical procedures in the treatment ofintraosseous defects are reported in Table 2. In gen-eral, defects with a mean presurgery probing depth of> 7 mm and an intraosseous component of the lesionof ≥ 5 mm were included. When the principle of thesingle flap approach or its variants was applied totreat deep intraosseous defects, substantial clinicaland radiographic outcomes were reported at 6–12 months following surgery (Table 2). The majorityof the studies showed a mean clinical attachmentlevel gain of at least 3.5 mm and a mean radiographicbone fill ranging from 33.7% to 78%. Mean probingdepth reduction ranged from 3.82 to 5.3 mm. Thepostoperative recession of the gingival margin wasgenerally within 1 mm (range: 0.1–1.5 mm) at
Trombelli et al.
98
Tab
le2.
Clin
ical
trials*ev
aluatingtheeffectiven
essofsim
plifi
edsu
rgical
proceduresin
thetrea
tmen
tofintrao
sseo
usdefects
Study
Exp
erim
entald
esign
Number
ofdefects
Intrao
sseo
us
componen
t(m
m)
Baselinepro
bing
dep
th(m
ean,m
m)
Flapdesignan
dreco
nstru
ctivetech
nology
Loca
liza
tionof
intrao
sseo
us
defects
Follow-u
p
(months)
Clinical
outcomes
Rad
iograp
hic
defect
fill(%
)
Patient-centered
outcomes
Clinical
attach
men
t
leve
lgain
(mm)
Pro
bing
dep
th
reduction
(mm)
Gingiva
l
recession
chan
ge†
(mm)
Trombelliet
al.2
009(49)
Caseseries
10Ran
ge,5
–14
Mea
n,8
.1
9.0
Singleflap
approac
h+graft/gu
ided
tissue
rege
neration
Alltooth
types
Ran
ge,6
–14
(mea
n,1
0.0)
4.8
5.2
0.4
Notav
ailable
Notav
ailable
Cortellin
i&Tonetti20
09(5)
Caseseries
15Ran
ge,4
–9
Mea
n,6
7.7
Modified
minim
ally
inva
sive
surgical
tech
nique
+en
amel
matrixderivative
Notav
ailable
124.5
4.6
0.07
Notav
ailable
Wee
k1:
nopatients
reported
pain;
threepatients
reported
slight
disco
mfort
Trombelliet
al.2
010(51)
Parallel-arm
randomized
controlle
dtrial
12Mea
n,6
.18.5
Singleflap
approac
halone
Alltooth
types
64.4
5.3
0.8
Notav
ailable
Notav
ailable
12Mea
n,8
.09.1
Singleflap
approac
h+graft/gu
ided
tissue
rege
neration
Alltooth
types
64.7
5.3
0.4
Notav
ailable
Notav
ailable
Cortellin
i&Tonetti20
11(6)
Parallel-arm
randomized
controlle
dtrial
15Mea
n,5
.27.5
Modified
minim
ally
inva
sive
surgical
tech
niquealone
Notav
ailable
124.1
4.4
0.3
77Wee
k1:
nopatients
reported
pain;
mea
ndisco
mfort
(100
-mm
visu
al
analogu
escale),
10.7
mea
nnumber
of
analge
sic
med
ications,0.4
15Mea
n,5
.37.8
Modified
minim
ally
inva
sive
surgical
tech
nique+en
amel
matrixderivative
Notav
ailable
124.1
4.4
0.3
71Wee
k1:
nopatients
reported
pain;
mea
ndisco
mfort
(100
-mm
visu
al
analogu
escale),
11.5
mea
nnumber
of
analge
sic
med
ications,0.3
15Mea
n,5
.27.3
Modified
minim
ally
inva
sive
surgical
tech
nique+graft/en
amel
matrixderivative
Notav
ailable
123.7
4.0
0.3
78Wee
k1:
nopatients
reportingpain;
mea
ndisco
mfort
(100
-mm
visu
al
analogu
escale),
12.3
mea
nnumber
of
analge
sic
med
ications,0.5
Trombelliet
al.2
012(52)
ParAlle
l-arm
randomized
controlle
dtrial
14Mea
n,5
.88.7
Singleflap
approac
halone
Alltooth
types
64.5
5.2
0.7
Notav
ailable
Notav
ailable
14Mea
n,5
.87.4
Double
flap
approac
h‡alone
Alltooth
types
63.4
3.9
0.5
Notav
ailable
Notav
ailable
Simplified procedures for intraosseous defects
99
Tab
le2.
(Con
tinued
)
Study
Exp
erim
entaldesign
Number
ofdefects
Intrao
sseo
us
componen
t(m
m)
Baselinepro
bing
dep
th(m
ean,m
m)
Flapdesignan
dreco
nstru
ctivetech
nology
Loca
liza
tionof
intrao
sseo
us
defects
Follow-u
p
(months)
Clinical
outcomes
Rad
iograp
hic
defect
fill(%
)
Patient-ce
ntered
outcomes
Clinical
attach
men
t
leve
lgain
(mm)
Pro
bing
dep
th
reduction
(mm)
Gingiva
l
recession
chan
ge†
(mm)
Farinaet
al.2
013(10)
Caseseries
43≥3mm
(on
radiograp
hs)
8.9
Singleflap
approac
halone
Singleflap
approac
h+en
amel
matrix
derivative
Singleflap
approac
h+graft
Singleflap
approac
h+graft/en
amel
matrix
derivative
Singleflap
approac
h+graft/gu
ided
tissue
rege
neration
Alltooth
types
63.4
4.7
1.3
Notav
ailable
Notav
ailable
Mishra
etal.2
013(25)
Parallel-arm
randomized
controlle
dtrial
14Mea
n,5
.08(on
radiograp
hs)
7.64
Modified
minim
ally
inva
sive
surgical
tech
niquealone
Alltooth
types
62.64
3.82
0.55
35.02
Notav
ailable
14Mea
n,5
.19(on
radiograp
hs)
7.73
Modified
minim
ally
inva
sive
surgical
tech
nique+platelet-derived
growth
factor
BB
Alltooth
types
63.00
4.18
0.82
36.20
Notav
ailable
Farinaet
al.2
014(9)
Pragm
atic
trial
12Mea
n,5
.58.8
Singleflap
approac
h+en
amel
matrix
derivative
Alltooth
types
63.8
4.9
1.2
Notav
ailable
Notav
ailable
12Mea
n,6
.18.6
Singleflap
approac
h+graft/en
amel
matrix
derivative
Alltooth
types
63.4
5.0
1.5
Notav
ailable
Notav
ailable
Farinaet
al.2
015(8)
Retrosp
ective
study
74Ran
ge,1
–14
Mea
n,5
.8
8.3
Singleflap
approac
halone
Singleflap
approac
h+en
amel
matrix
derivative
Singleflap
approac
h+graft/en
amel
matrix
derivative
Singleflap
approac
h+graft/platelet-derived
growth
factorBB
Singleflap
approac
h+graft/gu
ided
tissue
rege
neration
Alltooth
types
63.7
4.5
0.9
Notav
ailable
Notav
ailable
Schinca
glia
etal.2
015(39)
Parallel-arm
randomized
controlle
dtrial
15Mea
n,7
.78.7
Singleflap
approac
h+graft/platelet-derived
growth
factorBB
Alltooth
types
64.0
4.1
0.1
33.7
§Day
+1:
mea
npain
(100
-mm
visu
al
analogu
escale),
4.8;
mea
nnumber
of
analge
sic
med
ications,1.1
13Mea
n,5
.87.7
Double
flap
approac
h‡+graft/platelet-
derived
growth
factorBB
Alltooth
types
63.2
3.6
0.4
40.3
§Day
+1:
mea
npain
(100
-mm
visu
al
analogu
escale),
28.0;
mea
nnumber
of
analge
sic
med
ications,3.2
*Casereportswereexcluded
.†Positive
valueindicates
anincrea
se.
‡Accordingto
pap
illapreservationtech
niques
(2,3
).§Calcu
latedad
hoc
forthisreview
(datanotsh
ownin
thestudy).
Trombelli et al.
100
6–12 months postoperatively (Table 2). Althoughshowing that these simplified approaches may mini-mize the surgical trauma during the manipulation ofsoft tissues (Fig. 2), a high heterogeneity in gingivalrecession change was observed among and withinstudies. Recently, a retrospective analysis was con-ducted to evaluate the influence of patient-relatedand site-specific factors, as well as the adopted regen-erative strategy, on gingival recession change at6 months following a single flap approach (8). Theresults showed that the change in buccal recessionwas significantly predicted by the depth of the buccalosseous dehiscence and presurgery interproximalprobing depth (Fig. 3A). In particular, an increase inbuccal gingival recession may be expected when abuccal osseous dehiscence of > 2 mm and a presur-gery interproximal probing depth of > 5 mm are pre-sent. In light of these findings, the authors reinforcethe need to combine the single flap approach withspecific additional procedures/technologies when-ever a limited to null postsurgery shrinkage of the gin-gival margin is of paramount importance (such as inesthetic-sensitive areas). In this respect, differentauthors have proposed coronal advancement of thesingle flap approach (1) or the combination of a singleflap approach with an autologous soft-tissue graft (50,63) (Fig. 4) or a tridimensional collagen matrix (38).Although the combination of a single flap approachwith a connective tissue graft has been shown to leadto defect resolution with concomitant substantialroot coverage (63), the efficacy of these procedures incontrolling the postoperative recession increaseneeds to be evaluated further. The average chair-timefor a modified minimally invasive surgical technique,as measured from the delivery of local anesthesia tothe completion of sutures, ranged from 52.9 � 5.6 to58.9 � 6.2 min (5, 6).
Patient-centered outcomes
In a recent randomized clinical trial (39), significantlylower pain levels were self-reported during the firstpostoperative days by patients treated with a singleflap approach compared with patients undergoing adouble flap approach with papilla preservation tech-niques (Fig. 5). The mean number of analgesics con-sumed during the first 2 postoperative weeks was 2.73in the single flap approach group and 8.69 in the dou-ble flap approach group, with a significantly higherdose of analgesics being used in the double flapapproach group than in the single flap approachgroup (3.2 vs. 1.1, respectively) at day +1 (39). Datafrom other clinical trials on modified minimally inva-sive surgical techniques consistently showed low
postoperative pain levels and a limited consumptionof analgesics (5, 6). In the study by Cortellini &Tonetti (5), only three patients reported very limiteddiscomfort in the first 2 days of the first postoperativeweek, and none of the 15 treated patients reportedsignificant postoperative pain at week 1. In a morerecent study (6), none of the patients experiencedpostoperative pain at week 1. Average visual analoguescale scores (on a 100-mm scale) for postoperativediscomfort ranged from 10.7 to 12.3. The mean num-ber of analgesics was < 1, with a maximum of threeanalgesics being used during the postoperative period(6). Neither infective complications nor adverse reac-tions (edema or hematoma) were reported followingsimplified surgical procedures (5, 6, 8–10, 25, 39, 49,51, 52). These data support the safety of these proce-dures in the treatment of intraosseous lesions.
May simplified surgical proceduresenhance postsurgery woundstability?
The significance of primary closure and wound sta-bility as a determinant of the regenerative outcomehas been universally recognized (34, 59). In particu-lar, the first postoperative weeks seem to be criticalfor the maintenance of wound stability (18, 56, 59).Wound dehiscence may compromise wound stabil-ity, which in turn would jeopardize the cascade ofbiologic events leading to periodontal regeneration(14, 23, 58, 61). Furthermore, when flap surgery isused in association with regenerative devices, thepostoperative loss of primary closure may lead topartial or complete exfoliation of the implantedgraft, contamination of the membrane or prematureclearance of the bioactive agent. In this context, thesurgical management of the supracrestal soft tis-sues, including flap design and suturing technique,is of paramount importance in controlling thechances of wound failure during the early phases ofhealing (57). Data from several studies on the earlypostoperative healing achieved following a singleflap approach and modified minimally invasive sur-gery, either alone or in combination with bioactiveagents, indicate that the use of these techniquesmay result in high proportion of sites showing com-plete flap closure during the first postoperativeweeks (5, 6, 10, 39, 51). In particular, a retrospectiveanalysis of defects treated with a single flapapproach (10) consistently showed that 84% ofdefects showed complete closure of the incision
Simplified procedures for intraosseous defects
101
A B C
D E F
G H I
J K
M N
L
Trombelli et al.
102
wounds at 2 weeks, as assessed by an early healingindex score (55) of 1–3. In particular, 54% of thetreated defects showed optimal conditions (i.e. earlyhealing index score = 1) of wound closure (Fig. 2).The results also suggest an impact of the differentearly healing patterns on the 6-month clinical out-comes of the procedure (10), with a trend towardbetter clinical outcomes (greater clinical attachemntlevel gain, less buccal gingival recession increase)when defects showed optimal wound closure com-pared with incomplete wound closure. Morerecently, a randomized clinical trial demonstratedthat a single flap approach may optimize the qualityof early wound healing of defects compared with a
double flap approach based on papilla preservationtechniques (39). Surgical access was combined withrecombinant human platelet-derived growth factorBB and beta-tricalcium phosphate. At 2 weeks, 12sites in the single flap approach group and six sitesin the double flap approach group showed com-plete flap closure (i.e. early healing index = 1, 2 or3). The frequency of sites showing optimal woundhealing (i.e. early healing index = 1) was eight in thesingle flap approach group and three in the doubleflap approach group. Improved clinical outcomes insingle flap approach group compared with a doubleflap approach group were partly ascribed toenhanced early wound healing (39).
Fig. 2. Treatment of a narrow, mainly 3-wall intraoss-eous defect with the single flap approach in combina-tion with enamel matrix derivative. (A) Persistentbleeding, 8-mm pocket at the mesio-buccal aspect of aleft maxillary central incisor as observed at 6 monthsfollowing non-surgical therapy. (B) Pre-surgery radio-graph. (C) Sulcular incisions performed on the buccalaspect. (D) Oblique, butt-joint incision at the level of theinterdental papilla. (E) Elevation of a buccal single flap.(F) The defect is characterized by a narrow angle and a6 mm – deep intraosseous component (as measured atthe completion of surgical debridement). (G) The defectis mainly 3-walled. (H) Application of enamel matrix
derivative to root surface and defect. (I) Primary inten-tion wound closure. (J) Complete wound closure andabsence of fibrin line in the interproximal area (equiva-lent to an early healing index of 1, as proposed byWachtel et al. (55)) is observed at 2 weeks following sur-gery. (K, L) Clinical and radiographic aspect at 1 yearfollowing surgery. A clinical attachment gain of 5 mmand a residual probing depth of 2 mm have beenobtained. Also, a partial remineralization of the intraoss-eous component of the defect is evident. (M, N) Clinicaland radiographic aspect at 5 years following surgery.Probing depth is 3 mm and the residual angular compo-nent of the defect is minimal to null.
A
B
Fig. 3. Prediction of 6-month buccalgingival recession following singleflap approach. (A) Six-month gingi-val recession increase at the buccalaspect as predicted on the basis ofpresurgery probing depth (PD) andbuccal osseous dehiscence (bCEJ–BC). (B) Six-month gingival recessionincrease at the interdental aspect aspredicted on the basis of presurgeryprobing depth and treatment modal-ity. (reprinted from Farina et al. (8)).DBBM, deproteinized bovine bonemineral; EMD, enamel matrix deriva-tive; GTR, guided tissue regeneration;HA, hydroxyapatite; iREC, interproxi-mal recession, rhPDGF-BB, recombi-nant platelet derived growth factorBB. This figure is reproduced fromFarina et al. (8).
Simplified procedures for intraosseous defects
103
A
D E F
G H
J K
I
B C
Fig. 4. Single flap approach in combination with a connec-tive tissue graft to prevent postoperative gingival recession.(A, B) Nine-mm pocket positive to bleeding upon probingat the disto-buccal aspect of a maxillary canine. (C) Theintraosseous defect is accessed with a buccal single flapapproach. The defect is mainly 2-walled and is associatedwith the partial loss of the buccal cortical bone of theaffected tooth. (D) A connective tissue graft is harvestedfrom the tuber maxillae and fixed to mesial portion of thebuccal single flap with an internal mattress suture. (E) Theintraosseous component of the defect is treated with acombination of enamel matrix derivative and a bovine-
derived xenograft according to the sandwich technique. (F,G) The fixation of the graft to the single flap is completedwith an internal mattress suture. Wound closure in theinterdental area is achieved according to the originalsuturing technique described for the single flap approach(two internal mattress sutures) completed by an additionalinterrupted suture. (H) Wound healing at 1 week followingsurgery. (I) At 6 months following surgery, substantialregenerative outcomes (clinical attachment gain, 5 mm;probing depth reduction, 5 mm) have been obtained alongwith the stability of the gingival margin. (J, K) Clinical andradiographic aspect at 2 years following surgery.
Trombelli et al.
104
Single or double flaps?
Adequate surgical access to provide proper root/de-fect instrumentation of the intraosseous lesion is ofparamount importance in achieving the desired clini-cal and histologic outcomes. In this respect, theextent and morphology of the defect represents a keyaspect when selecting a flap design. On the otherhand, data from recent studies indicate that, shouldthe anatomic conditions permit it, a single flapapproach may lead to improved clinical outcomescompared with the double flap approach. In thisrespect, two- to three-walled intraosseous defectswere treated with surgical debridement using either asingle flap approach or a double flap approach (ac-cording to papilla preservation techniques) (52). Noregenerative devices were used in addition to surgicalaccess. At 6 months, treatment resulted in 1 mmgreater clinical attachment level gain and probingdepth reduction compared with elevation of a flap atboth buccal and oral aspects. A trend toward agreater clinical attachment gain for a single flapapproach compared with a conventional double flapapproach (papilla preservation techniques) was alsoreported in association with the use of a bioactiveagent + graft (39).
Data (Table 2) have shown that surgical access basedon the elevation of a single flap represents a valuabletreatment even when used per se (i.e. without theadditional use of reconstructive devices or bioactiveagents) (6, 25, 51, 52) (Fig. 1). The magnitude of clini-cal attachment level gain observed for the simplifiedprocedures (ranging, on average, from 2.6 to 4.5 mm)largely exceeds those reported for a double-flap
access, including the most conservative papillapreservation techniques (11). Obviously, the assess-ment of clinical improvement by probing recordingsprevents evaluation of the nature of the wound heal-ing following the tissue-maturation phase. The poten-tial of the simplified procedures per se to treatintraosseous lesions may partly explain the findingsfrom three randomized controlled trials evaluatingthe efficacy of different regenerative technologies (6,25, 51). In essence, the results from these studiesfailed to find any significant benefit from the use of aresorbable membrane with bone substitutes (51),enamel matrix derivative (with or without a xeno-graft) (6) or recombinant human platelet-derivedgrowth factor BB (25) when combined with a simpli-fied single-flap procedure. However, these findingsmust be interpreted with caution in view of the base-line defect characteristics and the appropriateness ofthe regenerative device selected for study. In thisrespect, in two studies (6, 25) defect selection resultedin mainly two- to three-walled defects with a narrowdefect angle, which are characterized by an enhancedhealing response (46, 53). Although limiting the indi-cation for a simplified procedure as a solo treatment,these results indicate that surgical access based on asingle flap may be effective when performed indefects more prone to spontaneous healing (Figs 1and 2). In the study by Trombelli et al. (51), the com-bination of a single flap approach with a resorbablemembrane and a hydroxyapatite-based graft resultedin incomplete early wound closure (i.e. early healingindex = 4) in five of 12 defects, whereas the single flapapproach group showed complete wound closure inall defects. Early wound failure may have partly com-promised the additional clinical benefit exerted byguided tissue regeneration compared with access flapsurgery (27), thus questioning whether the use of amembrane represents a suitable regenerative choicewhen combined to a single flap approach.
Fig. 5. Mean pain levels (as self-reported with a 100-mm visual ana-logue scale) following single flapapproach (SFA) or double flapapproach according to papillapreservation techniques (DFA). **:P < 0.01; *: P < 0.05. (reprinted fromSchincaglia et al. (39)). This figureis reproduced with permission fromthe American Academy of Periodon-tology.
Simplified procedures for intraosseous defects
105
A B C
J K L
D E F
G H I
Trombelli et al.
106
Which regenerative technology inassociation with simplified surgicalprocedures?
Several studies have demonstrated the effectivenessof simplified surgical procedures when these are usedin association with various regenerative technologies(Table 2). A series of studies investigated the combi-nation of a single flap approach with membranes orbioactive agents, with and without graft biomaterials(8–10, 38–40, 48–51). A modified minimally invasivesurgical technique was combined with bioactiveagents alone (5, 25) or with enamel matrix derivativeand a bovine-derived xenograft (6). The additionalbenefit of using a membrane–graft combination witha single flap approach has been challenged (51), andimproved treatment outcomes following use of bioac-tive agents (enamel matrix derivative, recombinanthuman platelet-derived growth factor BB), with orwithout bone substitutes, in association with the sin-gle flap approach, were recently reported (8, 9).Twenty-four deep periodontal intraosseous defectswere treated with a buccal single flap approach andenamel matrix derivative, with or without depro-teinized bovine bone mineral, according to the sur-geon’s discretion. Both treatments were clinicallyeffective in terms of clinical attachment gain andprobing depth reduction. Interestingly, the adjunctiveuse of deproteinized bovine bone mineral in wider,predominantly one-wall, defects seemed to compen-sate for the unfavorable effect of osseous characteris-tics on treatment outcomes (9). The results publishedin 2015 by Farina et al. (8) showed that the change ingingival recession at the interproximal level was sig-nificantly predicted by presurgery interproximalprobing depth and treatment modality. Defects trea-ted with a single flap approach in combination withenamel matrix derivative + deproteinized bovinebone mineral were less prone to recession increase
compared with defects treated with a single flapapproach with enamel matrix derivative (Fig. 3B).This finding was consistent with previous studiesshowing that the combined use of enamel matrixderivative and a graft may significantly temper thepostoperative recession compared with the use ofenamel matrix derivative alone in the treatment ofdeep intraosseous defects (13, 24, 62). On the basis ofthese findings, the combined use of enamel matrixderivative with a xenograft seems to be indicatedwhen deep intraosseous defects of unfavorable mor-phology are located at esthetic areas (Fig. 6).
Concluding remarks
Treatment of deep intraosseous defects in estheticareas implies clinical improvement of the lesion con-sistent with long-term survival of the affected tooth,preferably associated with true regeneration of thelost attachment apparatus, as well as preservation (orimprovement) of the esthetic appearance of thepatient. It is hoped that such treatment end pointsmay be reached by procedures (‘simplified’) which,on the one hand can be easily and successfullyapplied by the majority of clinicians and, on the otherhand, are well tolerated by patients in terms of post-surgical pain and discomfort, adverse events andcost.
In the present review, we have described the tech-nical aspects and analyzed the effect on clinical andpatient-centered outcomes of nonsurgical and sim-plified surgical procedures. On the basis of the evi-dence available, the following conclusions can bedrawn:� Whenever indicated, treatment selection should
be oriented toward the adoption of a ‘simplified’procedure. Data support the effectiveness of non-surgical and simplified surgical treatments whencompared with conventional approaches.
Fig. 6. Treatment of a deep, non-containing intraosseousdefect with the single flap approach in combination withenamel matrix derivative and a bovine-derived xenograft.(A–C) Clinical and radiographic aspect (as observed at6 months following initial therapy) of a maxillary centralincisor presenting a deep intraosseous defect at the mesio-buccal aspect (probing depth, 11 mm). (D) Horizontal, butt-joint incision at the level of the interdental papilla andintrasulcular incisions at adjacent teeth. (E) After the eleva-tion of a buccal single flap and the surgical debridement ofthe lesion and root surface, a wide, mainly 2-wall defectwith a 9-mm intraosseous component is identified. (F) Fol-lowing a first application of enamel matrix derivative, the
intraosseous component of the lesion is filled with a bovinederived xenograft mixed with the bioactive agent. (G) Appli-cation of second layer of enamel matrix derivative. (H)Wound closure is obtained with two internal mattresssutures and additional interrupted sutures (due to the widemesio-distal dimension of the interdental papilla). (I) At2 weeks following surgery, complete flap closure is main-tained, and a fibrin clot is present in the interproximal area(early healing index = 3; Wachtel et al. (55)). (J) Six-monthclinical attachment gain of 6 mm and residual probingdepth of 4 mm. A 1-mm increase in gingival recession canbe observed compared to pre-surgery. (K, L) Clinical andradiographic aspect at 5 year following surgery.
Simplified procedures for intraosseous defects
107
However, the appropriateness of such proceduresappears to be strictly related to patient and defectselection as well as to treatment end points.
� Preliminary data from recent studies have shownthat nonsurgical treatment using a minimallyinvasive technique may result in substantial clini-cal attachment level gain and probing depthreduction at 6–18 months following treatment,with limited remodeling of the gingival profile.Consistent with previous data (17), these studiesalso indicate that such a technique may be appro-priate in lesions with probing depth < 7 mm and alimited intraosseous component. However, itshould be borne in mind that histologic studies inhumans have indicated that the healing process ofintraosseous lesions following nonsurgical treat-ment is reparative rather than regenerative (12).Moreover, the long-term effectiveness of this min-imally invasive technique remains to be assessed.
� Should local conditions following nonsurgical ther-apy not be compatible with a good prognosis of thetooth presenting the defect (e.g. persistent bleedingpocket), corrective surgical treatment is recom-mended. After proper diagnosis of defect morphol-ogy, severe intraosseous defects can be successfullytreated by surgical procedures based on the eleva-tion of a single flap. Considerable clinical attach-ment level gain and probing depth reductionassociated with no adverse events have beenreported in observational and experimental stud-ies. A single flap approach was shown to be at leastas effective as traditional papilla-preservation tech-niques, when evaluated either as a stand-aloneprotocol or in combination with regenerativedevices. Successful outcomes may be, at least inpart, a result of enhanced wound stability duringthe early wound-healing phase.
� Simplified surgical procedures are associatedwith minimal esthetic impairment (i.e. post-treatment recession). The magnitude of therecession is similar to that observed followingthe minimally invasive technique. However, acertain amount of gingival shrinkage is to beexpected, even if the interdental papilla is leftuntouched. As the postoperative recessionincrease has been related to specific defectcharacteristics, variants of the single flapapproach, which include additional procedures/devices aimed at controlling the postsurgeryrecession, have been proposed (1, 38, 50 63).
� Surgical access based on a single flap without anyregenerative device may result in improved clini-cal conditions when this procedure is performed
in defects with a favorable prognosis (mainly two-to three-walled defects with a narrow angle).
� A single flap approach and a modified minimallyinvasive surgical technique have also been effec-tively used in combination with different regener-ative strategies, such as resorbable membranes orbioactive agents, with or without graft biomateri-als. Beside their potential for new attachment for-mation, bioactive agents have shown the mostappropriate regenerative device when combinedto a single flap approach.
� When dealing with deep intraosseous defects ofunfavorable morphology, particularly at estheticareas, the combination of bioactive agent andgraft biomaterial may ensure substantial attach-ment gain while limiting the postsurgery reces-sion.
� Simplified surgical procedures result in a moretolerable postoperative course when comparedwith conventional approaches. The lower postop-erative pain levels and dose of analgesics com-pared with conventional double flap proceduresmay be the result of reduced invasiveness andshorter operative time.
Despite these encouraging results, some of the keyprinciples of ‘simplification’ still need to be investi-gated for such procedures. In particular, limited to noinformation is currently available with regard to gen-eralizability, learning curve and cost–benefit ratio.Moreover, the clinical improvements (radiographicdefect fill, clinical attachment gain) observed whensimplified surgical procedures were used per se needsto be histologically characterized and evaluated longterm. Finally, the efficacy of single-flap approach vari-ants, which were proposed to preserve/improve thepre-existing esthetics of the patient, needs to be thor-oughly evaluated.
Acknowledgments
The study was entirely supported by the ResearchCentre for the Study of Periodontal and Peri-implantDiseases, University of Ferrara, Ferrara, Italy.
References
1. Checchi L, Montevecchi M, Checchi V, Laino G. Coronallyadvanced single flap in periodontal reconstructive surgery.Dent Cadmos 2008: 76: 46–58 (article in Italian).
2. Cortellini P, Prato GP, Tonetti MS. The modified papillapreservation technique. A new surgical approach for
3. Cortellini P, Prato GP, Tonetti MS. The simplified papillapreservation flap. A novel surgical approach for the man-agement of soft tissues in regenerative procedures. Int JPeriodontics Restorative Dent 1999: 19: 589–599.
4. Cortellini P, Tonetti MS. A minimally invasive surgical tech-nique with an enamel matrix derivative in the regenerativetreatment of intra-bony defects: a novel approach to limitmorbidity. J Clin Periodontol 2007: 34: 87–93.
5. Cortellini P, Tonetti MS. Improved wound stability with amodified minimally invasive surgical technique in theregenerative treatment of isolated interdental intrabonydefects. J Clin Periodontol 2009: 36: 157–163.
6. Cortellini P, Tonetti MS. Clinical and radiographic out-comes of the modified minimally invasive surgical tech-nique with and without regenerative materials: arandomized-controlled trial in intrabony defects. J ClinPeriodontol 2011: 38: 365–373.
7. Dundar N, Ilgenli T, Kal BI, Boyacioglu H. The frequency ofperiodontal infrabony defects on panoramic radiographs ofan adult population seeking dental care. Community DentHealth 2008: 25: 226–230.
8. Farina R, Simonelli A, Minenna L, Rasperini G, SchincagliaGP, Tomasi C, Trombelli L. Change in the Gingival MarginProfile After the single flap approach in PeriodontalIntraosseous Defects. J Periodontol 2015: 86: 1038–1046.
9. Farina R, Simonelli A, Minenna L, Rasperini G, Trombelli L.Single-flap approach in combination with enamel matrixderivative in the treatment of periodontal intraosseousdefects. Int J Periodontics Restorative Dent 2014: 34: 497–506.
10. Farina R, Simonelli A, Rizzi A, Pramstraller M, Cucchi A,Trombelli L. Early postoperative healing following buccalsingle flap approach to access intraosseous periodontaldefects. Clin Oral Investig 2013: 17: 1573–1583.
11. Graziani F, Gennai S, Cei S, Cairo F, Baggiani A, Miccoli M,Gabriele M, Tonetti M. Clinical performance of access flapsurgery in the treatment of the intrabony defect. A system-atic review and meta-analysis of randomized clinical trials.J Clin Periodontol 2012: 39: 145–156.
12. Greenstein G. Periodontal response to mechanical non-sur-gical therapy: a review. J Periodontol 1992: 63: 118–130.
13. Guida L, Annunziata M, Belardo S, Farina R, Scabbia A,Trombelli L. Effect of autogenous cortical bone particulatein conjunction with enamel matrix derivative in the treat-ment of periodontal intraosseous defects. J Periodontol2007: 78: 231–238.
14. Haney JM, Nilv�eus RE, McMillan PJ, Wikesj€o UM. Periodon-tal repair in dogs: expanded polytetrafluoroethylene barriermembranes support wound stabilization and enhancebone regeneration. J Periodontol 1993: 64: 883–890.
15. Harrel SK. A minimally invasive surgical approach for peri-odontal regeneration: surgical technique and observations.J Periodontol 1999: 70: 1547–1557.
16. Harrel SK, Wilson TG Jr. Minimally invasive periodontaltherapy: clinical techniques and visualization technology.Hoboken, NJ: John Wiley & Sons, Inc, 2015.
17. Heitz-Mayfield LJ, Trombelli L, Heitz F, Needleman I, MolesD. A systematic review of the effect of surgical debridementvs non-surgical debridement for the treatment of chronicperiodontitis. J Clin Periodontol 2002: 29 (Suppl. 3): 92–102.
18. Hiatt WH, Stallard RE, Butler ED, Badgett B. Repair follow-ing mucoperiosteal flap surgery with full gingival retention.J Periodontol 1968: 39: 11–16.
19. Hwang YJ, Fien MJ, Lee SS, Kim TI, Seol YJ, Lee YM, Ku Y,Rhyu IC, Chung CP, Han SB. Effect of scaling and root plan-ing on alveolar bone as measured by subtraction radiogra-phy. J Periodontol 2008: 79: 1663–1669.
20. Isidor F, Attstr€om R, Karring T. Regeneration of alveolarbone following surgical and non-surgical periodontal treat-ment. J Clin Periodontol 1985: 12: 687–696.
21. Kirkland O. The suppurative pus pocket; its treatment bymodified flap operation. J Am Dent Assoc 1936: 18: 1462–1476.
22. Larato DC. Intrabony defects in the dry human skull. J Peri-odontol 1970: 41: 496–498.
23. Linghorne WJ, O’Connell DC. Studies in the regenerationand reattachment of supporting structures of the teeth; softtissue reattachment. J Dent Res 1950: 29: 419–428.
24. Matarasso M, Iorio-Siciliano V, Blasi A, Ramaglia L, SalviGE, Sculean A. Enamel matrix derivative and bone grafts forperiodontal regeneration of intrabony defects. A systematicreview and meta-analysis. Clin Oral Investig 2015: 19: 1581–1593.
25. Mishra A, Avula H, Pathakota KR, Avula J. Efficacy of modi-fied minimally invasive surgical technique in the treatmentof human intrabony defects with or without use ofrhPDGF-BB gel: a randomized controlled trial. J Clin Peri-odontol 2013: 40: 172–179.
26. Murphy KG. Interproximal tissue maintenance in GTR pro-cedures: description of a surgical technique and 1-yearreentry results. Int J Periodontics Restorative Dent 1996: 16:463–477.
28. Nibali L, Pometti D, Chen TT, Tu YK. Minimally invasivenon-surgical approach for the treatment of periodontalintrabony defects: a retrospective analysis. J Clin Periodon-tol 2015: 42: 853–859.
29. Nibali L, Pometti D, Tu YK, Donos N. Clinical and radio-graphic outcomes following non-surgical therapy of peri-odontal infrabony defects: a retrospective study. J ClinPeriodontol 2011: 38: 50–57.
30. Nielsen IM, Glavind L, Karring T. Interproximal periodontalintrabony defects. Prevalence, localization and etiologicalfactors. J Clin Periodontol 1980: 7: 187–198.
32. Papapanou PN, Wennstr€om JL. The angular bony defect asindicator of further alveolar bone loss. J Clin Periodontol1991: 18: 317–322.
33. Papapanou PN, Wennstr€om JL, Gr€ondahl K. Periodontalstatus in relation to age and tooth type. A cross-sec-tional radiographic study. J Clin Periodontol 1988: 15:469–478.
34. Polimeni G, Xiropaidis AV, Wikesj€o UM. Biology and princi-ples of periodontal wound healing/regeneration. Periodon-tol 2000 2006: 41: 30–47.
36. Renvert S, Nilv�eus R, Egelberg J. Healing after treatment ofperiodontal intraosseous defects. V. Effect of root planingversus flap surgery. J Clin Periodontol 1985: 12: 619–629.
37. Ribeiro FV, Casarin RC, Palma MA, J�unior FH, Sallum EA,Casati MZ. Clinical and patient-centered outcomes afterminimally invasive non-surgical or surgical approaches forthe treatment of intrabony defects: a randomized clinicaltrial. J Periodontol 2011: 82: 1256–1266.
38. Rizzi A, Farina R, Simonelli A, Schincaglia GP, Trombelli L.Single flap approach in combination with different recon-structive technologies in the treatment of an intraosseousdefect associated with a buccal dehiscence. Dent Cadmos2013: 81: 299–307 (article in italian).
39. Schincaglia GP, Hebert E, Farina R, Simonelli A, TrombelliL. Single versus double flap approach in periodontal regen-erative treatment. J Clin Periodontol 2015: 42: 557–566.
40. Simonelli A, Farina R, Rizzi A, Trombelli L. Single flapapproach in the reconstructive treatment of a periodontalintraosseous defect associated with a root abnormality.Dent Cadmos 2013: 81: 365–373 (article in italian).
41. S€oder B, Jin LJ, S€oder PO, Wikner S. Clinical characteristicsof destructive periodontitis in a risk group of Swedish urbanadults. Swed Dent J 1995: 19: 9–15.
42. Soikkonen K, Wolf J, N€arhi T, Ainamo A. Radiographic peri-odontal findings in an elderly Finnish population. J ClinPeriodontol 1998: 25: 439–445.
43. Takei HH, Han TJ, Carranza FA Jr, Kenney EB, Lekovic V.Flap technique for periodontal bone implants. Papillapreservation technique. J Periodontol 1985: 56: 204–210.
44. Tal H. The prevalence and distribution of intrabony defectsin dry mandibles. J Periodontol 1984: 55: 149–154.
45. Tinti C. The interproximally connected flap to treat intra-bony defects: case reports. Int J Periodontics RestorativeDent 2007: 27: 17–25.
46. Tonetti MS, Lang NP, Cortellini P, Suvan JE, Adriaens P,Dubravec D, Fonzar A, Fourmousis I, Mayfield L, Rossi R, Sil-vestri M, Tiedemann C, Topoll H, Vangsted T, Wallkamm B.Enamel matrix proteins in the regenerative therapy of deepintrabony defects. J Clin Periodontol 2002: 29: 317–325.
47. Trombelli L, Farina R. Flap design for periodontal healing. In:Larjava H, editor. Oral wound healing: cell biology and clini-cal management. Oxford: Blackwell-Wiley, 2012: 229–241.
48. Trombelli L, Farina R, Franceschetti G. Use of the single flapapproach in periodontal reconstructive surgery. Dent Cad-mos 2007: 8: 15–25 (article in italian).
49. Trombelli L, Farina R, Franceschetti G, Calura G. Single-flapapproach with buccal access in periodontal reconstructiveprocedures. J Periodontol 2009: 80: 353–360.
50. Trombelli L, Farina R, Franceschetti G, Minenna L. Singleflap approach in reconstructive surgery of hard and softperiodontal tissues. Dent Tribune 2008: 4: 18–20 (article initalian).
51. Trombelli L, Simonelli A, Pramstraller M, Wikesj€o UM, Far-ina R. Single flap approach with and without guided tissueregeneration and a hydroxyapatite biomaterial in the man-agement of intraosseous periodontal defects. J Periodontol2010: 81: 1256–1263.
52. Trombelli L, Simonelli A, Schincaglia GP, Cucchi A, FarinaR. Single-flap approach for surgical debridement of deepintraosseous defects: a randomized controlled trial. J Peri-odontol 2012: 83: 27–35.
53. Tsitoura E, Tucker R, Suvan J, Laurell L, Cortellini P, TonettiM. Baseline radiographic defect angle of the intrabonydefect as a prognostic indicator in regenerative periodontalsurgery with enamel matrix derivative. J Clin Periodontol2004: 31: 643–647.
54. Vrotsos JA, Parashis AO, Theofanatos GD, Smulow JB.Prevalence and distribution of bone defects in moderateand advanced adult periodontitis. J Clin Periodontol 1999:26: 44–48.
55. Wachtel H, Schenk G, B€ohm S, Weng D, Zuhr O, H€urzelerMB. Microsurgical access flap and enamel matrix derivativefor the treatment of periodontal intrabony defects: a con-trolled clinical study. J Clin Periodontol 2003: 30: 496–504.
56. Werfully S, Areibi G, Toner M, Bergquist J, Walker J, RenvertS, Claffey N. Tensile strength, histological and immunohis-tochemical observations of periodontal wound healing inthe dog. J Periodontal Res 2002: 37: 366–374.
57. Wikesj€o UM, Crigger M, Nilv�eus R, Selvig KA. Early healingevents at the dentin-connective tissue interface. Light andtransmission electron microscopy observations. J Periodon-tol 1991: 62: 5–14.
58. Wikesj€o UM, Nilv�eus R. Periodontal repair in dogs: effect ofwound stabilization on healing. J Periodontol 1990: 61: 719–724.
59. Wikesj€o UM, Nilv�eus RE, Selvig KA. Significance of earlyhealing events on periodontal repair: a review. J Periodontol1992: 63: 158–165.
60. Wouters FR, Salonen LE, Helld�en LB, Frithiof L. Prevalenceof interproximal periodontal intrabony defects in an adultpopulation in Sweden. A radiographic study. J Clin Peri-odontol 1989: 16: 144–149.
61. Yumet JA, Polson AM. Gingival wound healing in the pres-ence of plaque-induced inflammation. J Periodontol 1985:56: 107–119.
62. Zucchelli G, Amore C, Montebugnoli L, De Sanctis M.Enamel matrix proteins and bovine porous bone mineral inthe treatment of intrabony defects: a comparative con-trolled clinical trial. J Periodontol 2003: 74: 1725–1735.
63. Zucchelli G, Mazzotti C, Tirone F, Mele M, Bellone P,Mounssif I. The connective tissue graft wall technique andenamel matrix derivative to improve root coverage andclinical attachment levels in Miller Class IV gingival reces-sion. Int J Periodontics Restorative Dent 2014: 34: 601–609.
