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#Periodontology

Periodontal Plastic Surgery

Supracrestal tissue attachment

• circumferential area between crestal bone and CEJ that provides space for junctional epithelium and connective tissue fibres to attach

Why opt for pre resto periodontal therapy

• stable gingival margins for aesthetics
• accurate crown margin placement
• reduce gingival inflammation for better visibility and lack of bleeding during resto

Preprosthetic surgical procedures

• mucogingival procedures
  • root coverage
  • gingival augmentation
• crown lengthening procedures
  • aesthetic
  • functional
• ridge preservation procedure
  • procedure done immediately following tooth extraction to preserve ridge for future implant, typically done with bone graft and resorbable membrane
• ridge augmentation procedure
  • complete on patient with ridge deformity to increase ridge dimensions and allowing placement of dental implant in a prosthetically favourable position

Perio Resto zones

• critical zones of interaction which must be harmonious for logn term trouble free resto
• why sungigval margins?
  • adequate resistance and retention form during crown preparation
  • significant contour alteration because of caries extent/tooth deficiency
  • to mask tooth retention interface within gingiva for aesthetics
• 
• crown margin
  • supragingival - preferential when possible as least perio impact
  • equigingival - well tolerated and margins more aesthetic/hidden
  • subgingival - greatest biologic risk, especially if violating gingival attachment apparatus
• interdental area
  • changes in shape of embrasure can impact height and form of papilla
  • if distance between interdental contact and interdental bone crest is less than 6mm (5mm or less), it is possible to rebuild papilla
  • restorative - apical position of contact point using material to change shape of teeth
  • surgical - perio regen to assist papilla reconstruction
  • ortho - uprighting tilted teeth to apically reposition contact point
• pontic area
  • hygienic (convex)
  • ridge lap (concave)
  • modified ridge lap (concave)
  • ovate (convex)
    

Biologic width

• use existing sulcus depth as landmark
• sungingival margin placement
  • PD 1-1.5mm, margin placement 0.5mm below gingival free margin
  • PD 1.5-2mm, margin placement up to half of sulcus depth
  • PD >2mm, gingivectomy to make PD 1.5 then follow that. This will reduce impression and margin finishing difficulties, avoid increased inflammation and risk of recession
  • 
• can be detected via presence of resto margin <2mm from alveolar bone, with inflamed gingiva without other factors evident
• consequences of biologic width violation
  • persistent inflammation (usually normal/thick biotype)
  • bone loss and gingiva recession (thin biotype)
• violation correction
  • crown lengthening
  • ortho extrusion

Surgical Crown Lengthening

Crown lengthening

• surgical procedure aimed at lengthening crown of tooth, via soft tissue (gingivectomy), hard tissue (ostectomy) or both
• aesthetic crown lengthening
  • typical objective to increase crown length in anteriors for ideal proportions
• functional
  • typical objective to improve length for new crown or resto to have improved resistance / retention
• indication
  • aesthetics
  • resto for equiging/subgingv fracture
  • resto of equiging/subging caries
  • placing subgingival restoration

Aesthetic indicxations

• gingival enlargement
• altered/delayed passive eruption
  • DGJ fails to migrate apically to the vicinity of the CJE
• insufficient clinical crown length
• vertical maxilalry excess
• short upper lip

Anterior aesthetics

• smile line
  • rest, speech, smile, laugh
• full smile
  • lip line, gingival display
• crown lengths
  • centrals = canines > laterals
  • normal height:width ratio (vertical maxillary excess or is it tooth based?)
  • short clinical crowns, incisal edge to CEJ and FGM (incisal wear, delayed/altered passive eruption)
• gingival scallop/zenith
  • most apical point at distal of central and canine
  • midpoint of lateral

Gargulio et al 1961 Biologic width

Preoperative planning

• remaining tooth structure
• anatomy of tooth
• status of adjacent teeth
• patient wishes
• cost:benefit ratio of procedure and subsequent restoraiton

Clinical evaluation

• soft tissue
  • gingival health
  • gingival contour
  • gingival phenotype
  • amount of attached keratinised tissue present
  • probing depths
• hard tissue
  • location of proposed restorative margin
  • occlusion
  • mobility of tooth to be crown lengthened

Radiographic evaluation

• location of proposed margin
• level of alveolar crest
• root length (crown:root ratio)
• root form
• root trunk length (location of furcations)
• endo status
• proximity to critical anatomical structures

Aesthetic evaluation

Techniques

• gingivectomy
  • alveolar boen crest already ideal, just soft tissue removal
• replaced flap
  • ostectomy and gingivectomy, only possible with sufficient keratinised tissue present at site
  • extrasulcular incision
• apically repositioned flap
  • bone removal with apical relocation of margin without removal of keratinised tissue
  • used when there is 2mm of keratinised tissue within site requiring additional crown length
  • intrasulcular incision with relieving incision past mucogingival junction

Healing after crown lengthening

• bragger et al 1992
  • N-85 cl with ostectomy
  • 6mo observation
  • gingival margin remained stable in 38%
  • changes of +- 1mm in 6mm of cases
• consider
  • changes of rebound and biotype
  • thick may rebound
  • thin may recede
  • aesthetic vs non aesthetic areas
  • retromolar tissue rebounds quickly (distal of lower 7s)
• rule of thumb
  • 6-8 weeks wait in non aesthetic
  • 4-6mo in aesthetic areas

Cost of crown lengthening

• tissue removal of tooth and adjacent teeth, which will increase crown to root ratio
• risk of furcation exposure which will decrease long term prognosis of the tooth

Pontic Site Development

Pontic site development

• ridge deficiency in horizontal or vertical dimension
• might impact aesthetic in high smile line
• hard or soft tissue grafting to plump out space
  • provide harmonious buccal contour
  • materials must remain stable

Soft tissue Grafts for Recession Defects

Is keratinised tissue necessary for health

• yes - lang and loe 1972
  • sites 2mm or more of KT clinically healthy
  • sites <2mm clinical inflammation
• no - Miyasato et al 1977, Wennstrom and Lindhe 1983, Dorfman et al 1980, Kennedy et al 1985, Wennstrom 1987b
  • no difference in inflammation or recession

Properties of Autogenous soft tissue grafts