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Journal of Oral Rehabilitation 2 1 28; 267 272

Position of the teeth on the edentulous atrophic maxillaL . V . J . LASS I LA* , E . KLEMETT I t V . P. LASS I LA * *Institute of Dentistry and Biomaterials Research,University of Turku, Finland, iFaculty of Dentistry, McGill University, Montreal, Can ada and *Departmen t of Prosthetics and StomatognathicPhysiology, University of Kuopio, Finland

SUMM RY For prosthetic trea tment of strongly at-rophic alveolar wall, some biometric methods havebeen developed. The measurements taken from plas-ter cast models of 230 edentulous, average29 9 years,and 125 dentulous post-menopausal women werecorrelated. In the edentulous maxilla the sagittalposition of canine teeth can be determined by th e oraledge of incisive papilla. The transverse position ofcanine teeth was on th e outer edge of th e alveolar wallbecause of t he extensive loss of buccal alveolar bone.On th e incisor area th e facial surfaces of th e centralincisors were de termined by th e oral edge of incisivepapilla and th e distance was about twice the lengthof the papilla. The sagittal position of th e first premo-lars was one-third and t he first molars two-thirds th elength of t he palate from t he plane of the labial edgeof incisive papilla. The transverse position of th e

IntroductionAtrophy of the alveolar process after loss of teethprogresses with variable speed, as has been found bymany researchers (Carlsson Bergman Hedegird,1967; Tallgren, 1972; Watt Likeman, 1974). Thereasons for the speed of resorption can be related to thecharacteristics of the individual such as: age, certainsystemic diseases, and also to poor fitting dentures(Kelly, 1972; Von Wowern Stoltze, 1979, 1980;Tallgren et al., 1980; Ettinger Beck, 1983; Kalk Baat,1989; Kribbs et al., 1990; Klemetti Vainio, 1994).

Very valuable information about alveolar resorptionhas been obtained from longitudinal studies of edentu-lous patients (Carlsson, Thilander Hedegird, 1967;Tallgren, 1967; Atwood Coy, 1971; Douglass et al.,1993). The methods used in these investigations have

premolars and molars was determined by the scar-line, which is a cord-like elevation or track on thealveolar mucosa after extractions of th e teeth. Ac-cording to the comparative method, t he position ofth e scar-line differed from the lingual gingival marginline and was situated about half breadth of th e toothin a buccal direction from it. The transverse positionof premolar and molar in th e edentulous maxilla isabout th e middle of th e scar-line in a facio-buccaldirection. In th e setting of the artificial teeth, th efacial surfaces of these te eth should be on average5-0-6.0 mm sideways from t he scar-line, whilst th etotal bilateral breadth of t he alveolar wall in thesulcus area was on average 1-0-2.0 mm larger.KEYWORDS alveolaratrophy, biometric denture de-sign

been X-ray cephalometric tracing or pantomographicmethods. Other researchers have determined the corre-lation of t he mineral status in the skeleton with thedensity of alveolar bone (Humphries Devlin Wor-thington, 1989; Von Wowern Kollerup, 1992; Hirai etal., 1993; Klemetti Vainio, 1993; Klemetti eta l . , 1993;Klemetti, Kroger Lassila, 1997). To facilitate theclinical estimation of the amount of alveolar bone loss,Likeman Watt, 1974, Watt Likeman, 1974 and Watt

McGregor, 1986 have presented some guides, such asthe incisive papilla and the remnan t of the lingualgingival margin line, as landmarks for determining theposition of alveolar bone and teeth.

Extensive loss of alveolar bone and deformation ofthe alveolar wall during a long edentulous period,indicate that more specific instructions are needed tosupport what can be difficult prosthetic treatments.

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P OS I TI ON O F M A X I L L A R Y TEETH 269

IP Table 2 Difference between the distances from IP to CP and tothe plane through the oral edge of incisive papilla OP) indentulous maxilla

Fig 1. Diagrammatic representation of maxilla with profile ofthe scar line (unbroken line, S ) and the lingual gingival marginline (broken line, T ) and incisive papilla to the natural teeth areshown. Other reference planes and lines: IP, incisive plane; LP,labial plane of papilla; OP, oral plane of papilla; CP, caninusplane; PP, first premolar plane; MP, first molar plane; FP, foveolaplane; a, alveolar line; and f, facial surface line.

loss of buccal alveolar bone and so the position of theincisors was determined by the distance of the oraledge of the incisive papilla.

The total breadth of the facial surfaces and the eden-tulous and dentulous alveolar walls in reference re-gions was measured.

For comparisons of the means analysis of varianceANOVA ) was used.

Distances (mm) Mean s .d .IP-CP 11.82 1.30 110IP-OP 12.08 1.18 110Difference 0.26 P = N S

ResultsSagittal position of the canine teeth and central incisorsThe difference between the distances from the planepassing through the facial surface of the central incisors(IP) to the plane passing through the canine teeth (CP)and to the plane passing through the oral edge ofincisive papilla (OP) was on average 0.26mm andstatistically non-significant (Table 2 ) .

The CP also passed very near by the oral edge ofincisive papilla and the sagittal position of canine teethin the edentulous maxilla can be defined well with thislandmark.

The position of the facial surface of the central in-cisors can be determined also according to the oraledge of the incisive papilla. The distance from the IP tothe OP was on average 12 .0mm. This is about twicethe average length of the papilla in the edentulousmaxilla (Table 3 ) .

Sagittal position of the first premola r an d the first molarIn dentulous maxilla, the distance from the LP, theplane passing through the labial edge of incisive papillato the first PP, did not differ significantly (P> 0.1) fromthe length of one-third of the palate length, nor did the

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270 L . V . J . LA S S ILA e t a l .

Table 3. Correlation in length of incisive papilla between max-illa with natural teeth and a edentulous maxillaLengths (mm) Mean s.d. n Lengths (mmj Mean s.d. n

Table 5. Difference in length of the palate (LP-FP) between amaxilla with natural teeth and edentulous maxilla

Dentulous maxilla 7.74 1.55 120 LP-FP (dentulous) 44.90 3.34 89Edentulous maxilla 6.27 I .42 228 LP-FP (edentulous) 43.27 3.75 228Difference 1.49 PO.O01

distance to the first molar plane (MP) from the length position of these teeth in the edentulous maxilla is alsoof two-thirds of the palate length (Table 4) . in the middle of the scar-line in the facio-lingual

The length of the palate from the labial edge of IP to direction.the FP was on average 1.6 mm longer in dentulous In the presence of extensive loss of buccal alveolarmaxilla than in the edentulous maxilla (Table 5 . The bone the position of the scar line in canine region wassame difference can be seen in relation of the length of at the buccal edge or totally outside the alveolar wall.incisive papilla in dentulous and edentulous maxillas Therefore, the canine teeth are situated so that three-(Table 3 . The reason for this is the extensive loss in quarters of the facio-ligual breadth (about 6 m m ) isthe buccal alveolar wall and deformation of the labial outside the alveolar wall.edge of papilla. The difference is clear but it will be The total breadth of alveolar wall in the edentulouseliminated in the relative measurements of the practi- maxilla was about 2 - 3 mm larger than that of thecal technique for removable dentures. scar-line in premolar and molar region and showed

Thus, the sagittal position of the first premolar and tha t the atrophy of the wall was on average marked inthe first molar can be found in edentulous maxilla by these regions, but the variances were quite large. Thedividing the length of palate into three equal parts total breadth of the alveolar wall in the sulcus area inwhere t he PP is one-third and MP two-th irds back dentulous maxillas differed very little from the line offrom the LP. the facial surface of the teeth (1.0-2.0 mm). However,

it must be taken into consideration when moulding theTransverse position of the reference teethThe transverse position of canines, first premolars and

record blocks and bases of dentures for an edentulousmaxilla (Fig. 2b).

first molars on the CP, PP and MP were determined bycomparing the bilateral distances of lingual gingival Discussionmargin lines beside the teeth and the bilateral distancesof the scar-lines in the same region in the edentulousmaxilla (Fig. 1) . According to the measurements theposition of the scar-line in premolar and molar regionwas buccal to the lingual gingival margin line. Thedifference in the total breadth was 8.47 mm in premo-lar region and 10.6 mm in the molar region, which didnot differ statistically from the facio-lingual breadth ofthese teeth (Table 6). In practical application this isabout 5.0mm in the premolar region and about6.0 mm in the molar region. The correct transverse

The alveolar bone loss in maxilla, especially in the areaof t he canine and incisor teeth, as a result of long termedentulousness and poor fitting dentures with insuffi-cient opposing dentition, has been discussed previouslyby Klemetti et al. (1996).The incisive papilla appears tobe a good landmark for the sagittal position of thecanine and anterior teeth, in spite of the deformationof the labial edge confirming previous work (WattLikeman, 1974; Likeman Watt, 1974; Watt Mc-Gregor, 1986). The oral edge of incisve papilla wasgenerally unaltered in the edentate. When the mea-

Table 4. Length of the palate (LP-FP) in dentulousmaxilla and correlation between the distances fromthe plane through t he labial edge of incisive papilla tothe plane of first premolars (LP-PP) and first molarsthe length of palate

Distances (mmj Mean s.d. 1/3, 213 x LP DifferenceLp-FpLp-pp

44.90 3.3414.47 2 .35 1 3 X LP-FP= 14.96 0.49 P>O.1(LP-MP) with the distance one- third and two-thirds of ~ p - ~ p 29.15 3.20 213 x LP-FP= 29.93 0.78 PZ0. l

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P OS I TI ON O F MAXILLARY T E E T H 271

surements of the length of the palate in edentulousmaxilla were made from the labial edge of the papilla,the standard deviation was quite great, but slight inac-curacy in the total length of the palate does not haveparticular effect on the practical treatment for remov-able dentures.

Klemetti et al . 1996) and Klemetti et al. (1997) intheir study have divided the length of the palate intothree equal parts to determine the location of themolar region in the edentulous maxilla. The presentresults have cofirmed a method of locating the positionof the first premolars and the molars in the edentulousmaxilla.

The scar-line on the edentulous alveolar wall wasgenerally easy to see in the area of the premolar andmolar teeth and it was in the middle of original alve-olar wall. The correct position for these teeth is in themiddle of this line in the facio-lingual direction. Ac-cording to our study the position of the scar-line in theedentulous maxilla differed from the lingual gingivalmargin line, which was used as landmark line in theprevious studies by Watt Likeman (1974) and Like-man Watt (1974). The reason for the divergence ofresults could be based on the fact that our subjectswere edentulous for twice as long. The present studygives the possibility to estimate more exactly the posi-tion of teeth and also the breadth of t he space buccallyoutside of the alveolar wall, which has to replaced inprosthetic treatment.

In severe atrophy of the anterior area of the alveolarwall, the scar-line sometimes disappears totally and thepalatal rnucosa extends to the anterior side of the wall.

Therefore, the transversal position of the canines wason the outer edge of the alveolar wall and the correctposition for the incisor teeth could be determined onlyby the oral edge of the incisive papilla.

The results of these measurements may not alwaysbe completely applicable in clinical use, e.g. because ofprevious adaption of patients to incorrect dentures. Inthese cases, however, it is possible to compromise.These biometric quides can give considerable help inthe planning of prosthetic treatment, especially forformulating record blocks and setting of artificial teethfor patients, with a long edentulous history.

In conclusion, according to the result of the presentstudy in denture treatment of atrophic alveolar wall ofthe edentulous maxilla, the correct position for thedifferent groups of teeth can be found with the follow-ing criteria.(1) The sagittal position of central incisors can be deter-mined by the oral edge of incisive papilla, and thedistance s about twice the length of the papilla.2) The sagittal position of the canine teeth are also

related to the oral edge of IP and in transverse settingan average of three-quarters of these teeth have to beoutside of the alveolar wall.3 ) The sagittal position of the first premolar is one-

third and the first molar two-thirds the length of thepalate from the labial edge of incisive papilla. Thetransverse position of premolar and molar is in themiddle of the scar line, and the distances of the facialsurfaces are about 5-6 mm buccal from this landmarkline.

Table 6 Differences between bilateral dis-tances of lingual gingival margin lines of theteeth T) and the scar-lines S) (edentulousmaxilla) in same region and correlation withfacio-lingual breadth of teeth

Facio-lingual breadth of teethDistances (mm) Mean s.d. z Mean s.d. DifferenceCanine teeth

13T-23T 24.25 1.92 11513s-23s 26.32 3.54 227

Difference 2.07 8.05 0.68 5.98First premolars

14T-24T 27.75 2.34 9014s-24s 36.22 3.29 229

Difference 8.47 8.85 0.54 0.38 P = NSFirst molars

16T-26T 34.28 3.21 10716s-26s 44.89 2.92 229

Difference 10.61 10.77 1.13 0.1 6 P = N S

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ReferencesATWOOD, .A . COY,W.A. (1971) Clinical, cephalometric and

densitometric study of reduction of residual ridges. Journal ofProsthetic Dentistry, 26 280.

CARLSSON,.E., BERGMAN,. HEDEGARD,. (1967) Changes incontour of the maxillary alveolar process under immediatedentu res. A longitudinal clinical and X-ray cephalometric studycovering 5 years. Acta Odontologica Scandinavica, 25 45.

CARLSSON,.E., THILANDER,. HEDEGARD,. (1967) Histologicchanges in the upper alveolar process after extractions with orwithout insertion of a n immediate full denture. Acta Odontolog-ica Scandinavica, 25 21.

DOUGLASS,.B., MEADER,., KAPLAN,A. ELLINGER,.W. (1993)Cephalometric ev aluat ion of th e changes in patients wearingcomplete dentures. A 20-year study. Journal of Prosthetic Den-tistry, 69 270.

ETTINGER,.L. BECK,J.P. (1983) Medical and psychosocial riskfactor in the denta l treatment of th e elderly. International DentalJournal, 155 203.

HIRAI, ., ISHIJIMA,., HASH IKAWA , YAJIMA, . (1993) Os-teoporosis and reduct ion of residual ridge in edentulous pa-tients. Journal of prosthetic Dentistry, 69 49.

HUMPHRIES ,., DEVLIN, . WORTHINGTON,. (1989) A radio-graphic investigation into bone resorption of mandibular alve-olar bone in elderly edentulous adults. Journal of Dentistry, 1794.

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