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PONTICS
DefinitionPontic is defined as an artificial tooth on a fixed dental prosthesis that replaces a missing natural tooth , restores its function and usually fills the space previously occupied by the clinical crown.
Ideal Requirements1-A pontic should restore the function of the tooth it replaces 2-It should provide good esthetics 3-It should be biocompatible with continued oral health and comfort. 4-It should permit effective oral hygiene. 5-It should preserve underlying mucosa and bone.
Pontic designProper Pontic Design leads to Success of the FPD *The pontic must be carefully designed and fabricated not only to facilitate plaque control of the tissue surface and around the adjacent abutment teeth but also to the existing occlusal considerations . *The design of pontic depends on various factors: Pretreatment assessment ,Pontic classification ,Biological considerations ,Mechanical considerations and Pontic fabrication .
A) Pretreatment assessmentCertain procedures enhance the success of pontics they are: 1 Pontic space 2 Residual ridge contour 3 Gingival architecture preservation
B) Classification of ponticsPontic designs are classified into two major groups: *Those that contact the oral mucosa *Those that do not **Based on type of materials for fabrication **Based on method of fabrication Pontic selection is based primarily on esthetics and oral hygiene.
AMUCOSAL CONTACT : Ridge lap Modified ridge lap Ovate Conical NO MUCOSAL CONTACT : Sanitary/ hygienic Modified sanitary/ hygiene
BBased on type of material used : Metal & Porcelain Veneered Metal & Resin Veneered All Metal All Ceramic
PONTIC DESIGN
MATERIALS
LOCATION
SANITARY/HYGIEN ICSADDLE-RIDGELAP CONICAL
All metalNot recommended All metal Metal ceramic All resin All metal Metal ceramic All resin All metal Metal ceramic All resin
Posterior mandibleNot recommended Molars without esthetic requirement High esthetic requirement Very high esthetic requirement
MODIFIED RIDGELAP OVATE
PONTIC DESIGN SANITARY/HYGIENIC SADDLE-RIDGE-LAP CONICAL
ADVANTAGES Good access for oral hygiene esthetic Good access for oral hygiene Good esthetics Superior esthetics Negligible food entrapment Ease of cleaning
DISADVANTAGES Poor esthetics Not amenable to oral hygiene Poor esthetics
MODIFIED RIDGE-LAP OVATE
Moderately easy to clean Requires surgical preparation Not for residual ridge defects
PONTIC DESIGN
INDICATIONS
CONTRAINDICATION S
SANITARY/HYGIENIC
Non esthetic zones Impaired oral hygieneNot recommended Posterior areas where esthetic is minimal consideration Most areas with esthetic consideration Desire for optimal esthetics High smile line
Where esthetics is essential Less vertical dimensionNot recommended Poor oral hygiene
SADDLE-RIDGE-LAP CONICAL
MODIFIED RIDGE-LAP OVATE
Where minimal esthetic consideration exists Unwillingness for surgery Residual ridge defects
Design considerations for anterior pontic : 1-All surfaces should be smooth , convex and properly finished . 2-Contact with labial slope of the ridge should be minimal and pressure free. 3-A large contact with the ridge is provided for a natural look. 4-Lingual contour should be in harmony with that of the other teeth.
Optimal pontic design
C) Biological considerationsThe pontic has to preserve the surrounding biological tissues 1-Ridge contact Pressure free contact Should be evaluated during try-in stage Contact should be on the keratinized attached tissue 2-Oral hygiene considerationsToxins of microbial plaque Gingival surface of pontic , not accessible to bristles of tooth brush
3-Pontic materialPontic should have following qualities *Biocompatible-glazed porcelain , gold or metallic and acrylic *Rigidity resist flexure during mastication *Strength metal ceramic junction - in case of decresed vertical space for pontic *Longevity *Provide good esthetic results
4-Occlusal forces*Reducing the buccolingual width by 30% Problems with narrowing the occlusal table Buccolingually collapsed ridges
Causes of mechanical failure of an FPD 1-Poor tooth preparation 2-Improper choice of materials 3-Poor frame work design 4-Poor occlusion 5-Long span Fixed Partial Dentures 6-Greater flexing 7-Displacement effects increase with cube of span length 8-Extension of ceramic on occlusal surfaces
D) Mechanical considerations
E) Esthetic considerations
Gingival Interface*Pontic simulation to natural tooth is most challenging at pontic tissue interface *If original tooth contour is followed , pontic looks unnaturally long incisogingivally . . . SO , make use of Modified ridge lap Ovate pontics
Incisogingival Length*Height of tooth is more obvious *Recontouring the gingival half of the labial surface *In case of moderate to severe bone resorption ,pontic can be made to simulate a normal crown and portion of root
Mesio - distal widthSpace for tooth may be less or more than the adjacent tooth-orthodontic treatment -incorporation of visual perception principles to the pontic Width of the tooth is identified by -Relative position of mesiofacial and distofacial line angles -Overall shape -Light reflection between the line angles Space discrepancy can be compensated by altering the shape of the proximal areas
Basic principles of pontic designOcclusal surface: within the boundaries of the lines connecting buccal and lingual surfaces of abutment teeth Buccal ,lingual or palatal surfaces: should lie in same plane as the surfaces of adjacent teeth Angle of contact: junction of pontic with gingiva should be as wide as possible Area of contact: should be as minimal as possible Mucosal contact: should be either convex or flat Embrassures: should be as wide as possible
Fabrication of pontics*Custom-made pontics 1-Anatomic contour waxing 2-Prepare the pontic approximatley and adapt it to ridge 3-Pour molten wax into the impression of diagnostic waxing or provisional restoration *Prefabricated pontics 1-Cut-back procedure 2-Metal prepartion 3-Porcelain application
AVAILABL E PONTIC SYSTEMSMETALCERAMIC
ADVANTA DISADVAN GES TAGESESTHETIC BIOCOMPATIBLE DIFFICULT WHEN ABUTMENT IS NOT METALCERAMIC WEAKER THAN ALL METAL
INDICATI CONTRAI ONS NDICATIO NSMOST SITUATIONS LONG SPANS WITH HIGH STRESS
ALL METAL
STRENGTHSTRAIGHTFORW ARD PROCEDURE
NONESTHETIC
MANDIBULAR MOLARS ESPECIALLY UNDER HIGH BITE FORCEAREAS OF HIGH ESTHETIC CONCERN
WHERE ESTHETICS IS IMPORTANT
FIBRE REINFORCE D ALL RESIN
CONSIDERATIVE WHEN USED WITH INLAY PROCEDURE ESTHETICS EASE OF REPAIR
LIMITED TO SHORT SPANS
LONG SPAN PARTIAL FIXED DENTAL PROSTHESIS
Prefabricated pontics
Saddle or ridge lap pontics
Modified ridge lap
Sanitary or hygienic
Conical pontic
Ovate pontic
Pontic selectionRetainers*Incase of PFM retainers , PFM pontics are used *In case of partial veneer retainers , prefabricated facings are indicated *In case of full metal retainer , all metal pontic is used
Recommendations for EstheticsMaxillary anterior segment modified ridge lap is the design of choice Multiple missing teeth minimize the interproximal embrassure
Occlusogingival height and Mesiodistal width of pontic space*Long span areas with reduced occlusaogingival heightporcelain fracture *Ridge resorption and ridge contour Extensive ridge resorption Tissue clearance of 3mm Ridge augmentation and recontouring
References1-Stephen f rosenstiel: contemporary fixed prosthodontics . Third edition 2-Herbert t. shillinburg: Fundamentals of fixed prosthodontics . Third edition 3-William f.p malone: tylmans theory and practice of fixed prosthodontics . Eighth edition 4-Johnston: modern practice in fixed prosthodontics.fourth edition 5-Sohnmit singh: pontic designs . Famdent practical dentistry handbook 2002.p.no41-46