Restorative-Periodontal inter-relationships

1. Restorative-Periodontal inter-relationships Dr. Ibrahim Al-Sulieman BDS (JUST), MClinDent Pros. (UoEdi) Office hours Wed 9-12 DTC (105)

2. Introduction The Golden Rule: “Periodontium is the foundation of teeth”

3. Compromised periodontium Compromise: • Ginigval health • Restoration margin and Esthetics

4. So its mandatory that the health of ginigival tissues be established and gingival biotype be considered before any restorative procedure is started. People with pre-existing periodontal problems show exaggerated responses to slightest insults.

5. The advantages of achieving healthy periodontium: • Achieve stable gingival margins and interdental papilla. • Reduce the gingival bleeding especially with subgingival preps. • Gingival retraction and impression can be achieved successfuly.

6. Lecture outline Remember to consider the health of the periodontium: BEFORE starting treatment: • BPE/CPITN • Gingival biotype • Sulcus depth DURING treatment: • Tooth preparation and margin placement • Biological width • Soft tissue management and gingival retraction • Marginal fit • Crown contour • Pontic design • Subgingival debris • Restorative material AFTERtreament: Maintenance

7. Basic periodontal examination (BPE) It is a simple and rapid screening tool used to indicate the level of examination needed and provides basic guidance on treatment needs. • Similar to CPITN • Developed by BSP 1986 • Should be recorded for all new restorative patients • Dentition is divided into sextants (Minimum 2 teeth,-M3)

8. Scoring codes

9. BPE • Score 3 (full examination of the sextant) • Score 4 (full examination of the entire dentition)

10. Interpretation of BPE • Radiographs for sextants with 3,4 scores

11. Gingival biotype

12. Gingival biotype Classified into: • Flat thick • Thin scalloped Based on: • B-L thickness of gingiva • Shape of the gingival margin • Width of keratinized gingiva • Thickness of underlying alveolar process (Bone sets the tone, and tissue is the issue!!)

13. Significance of gingival biotype • Susceptibility to recession (trauma) Thin biotype is more susceptible to recession (Thin crestal bone, less than 2 mm BW) • Predicting esthetic success of implant restorations (papilla, and metal shine through) • Collapse of the socket after extraction is more likely with thin biotype

14. Attached gingiva • No minimal width of attached gingiva has been established as a standard for gingival health. • The presence of wider attached gingiva (1-3mm) is important, especially when the restoration margin is located subgingvally or the tooth is acting as an abutment. • Teeth with narrow zones of keratinized gingiva and subgingival margins has been found to be associated with greater gingival inflammation scores than restored teeth with wide zones of attached gingiva. • Muco-gingival surgery can be performed to increase the width of the attached gingiva.

16. Previous knowledge of sulcus depth is important for: • Subgingival penetration • retraction

17. How to take care of the periodontium during treatment • Tooth preparation and margin placement • Biological width • Soft tissue management and gingival retraction • Marginal fit • Crown contour • Pontic design • Subgingival debris • Restorative material

18. Tooth preparation and Margin placement • Adequate reduction esp. finish line • Respect the parabolic nature of periodontal housing

19. The three options for marginal placement are : • Supragingival • Equigingival • Subgingival • The least impact on the gingival health is the supragingival margin.

20. Subgingival margins • Difficult to: Prepare, record, check fit of rest., maintain • Might violate BW • Associated with more BOP, recession and inflammation scores regardless of sulcus penetration (Silness 1980) • In one study (Valderhaug J. et al 1993): 68% of the crown margins initially were located sub-gingivally at the basis observation, only 27% remained subgirigivally at the 15-year observation.

21. Subgingival margins Indications: • Increase the preparation length to increase the retention form of short crowns. • Caries extending subgingivally. • Pre-existing restoration • Fracture line extending below the gingival margin. • Aesthetic reasons especially for the labial surface of max. ant. teeth. • To achieve a ferule effect around the post in endo treated teeth. If it was for esthetics, minimal subgingivalextention is recommended (0.5-1mm) JUST SUBGINGIVAL Generally, not closer than 0.5 mm to the JE

22. Biological width • The dimension of space that the healthy gingival tissues occupy above the alveolar bone is termed as biologic width. • Biologic width= 2 mm • Connective tissue attachment= 1.07 mm • Junctional epithelium= 0.97 mm

23. Biologic width

24. Upon the invasion of the biological width one of two consequences can develop: • Unpredictable bone loss and gingival recession as the body attempts to recreate the space between the margin and the alveolar bone. • No change in the alveolar bone level, but gingival inflammation develops and persists.

26. Evaluation of biologic width: • Radiographically • Useful for proximal areas only. • Bone sounding • A probe is pushed through the sulcus of the anesthetised tooth to the underlying bone. Correction of BW violation: • Surgery (crown lengthening procedure) • Orthodontic extrusion

27. Soft tissue management and Gingival retraction • Many techniques, none is without adverse effects on the gingiva, most notably gingival recession • Most common is using retraction cords impregnated with astringents • The damage caused by the retraction cord depends on (Ferencz J. L. 1991): • the chemical agent (Aluminum chloride is the least irritating ) • Packing force • length of time the cord left in place

28. Tips • Establish gingival health • Avoid forceful packing • Place retraction cord for at least 4 min and leave within 10 min (Plain cords are safe to be used for up to 30 min) • Moisten the cord before removal • Remove all remnants of impression material for the sulcus • If the impression is to be retaken, it should be delayed until complete healing is achieved (10-14 days) (Harrison 1961)

29. Marginal fit • I has been found that the greater the marginal gap the greater the gingival inflammation. • Large gaps increase in bacterial accumulation. • 40 µm gap is considered to be the least acceptable clinically detectable marginal discrepancy.

30. Overhanged subgingival margins have been found to shift the crevicular bacterial flora toward G-ve melanogenic bacteria commonly associated with periodontitis. • Overhanged margins can lead to increased plaque accumulation and gingival bleeding tendency.

31. Crown contours Different thiories for contours: • Food deflecting theory (convexcity) • Muscle action theory (no overcontouring), • Plaque-retention theory (access for cleaning) • Anatomic theory Rules • The facial convexity should not bulge more than 0.5 mm beyond the CEJ. This maximum convexity is present in the gingival third.

33. Lingual convexity is found in the gingival third of most teeth but in the middle third in mandibular molars and premolars. It should not bulge more than 0.5 mm greater than CEJ. • Proximal contact points are in the occlusal third of the crown • The contact area should be tight (but not too tight) to prevent food impaction, and allow easy flossing. • Proximal contact points are buccal to the B-L center except between maxillary molars it is in the middle third.

34. Proximal contacts

35. Proximal surfaces are always flat or slightly concave B-L and O-G for healthy interdental papilla. • Marginal ridges: should be at the same height to prevent food retention. • Marginal ridges converge toward the lingual surface, thus the lingual embrasures are wider lingually when viewed occlusally.

36. Interproximal embrasure form

37. The ideal interproximal embrasure should house the gingival papilla without impinging on it or leaving a space a space that would trap food or be aesthetically unpleasing • 5 mm between bone crest and contact point

38. Inadequate tooth reduction  bulky restoration to improve strength • In furcation involved teeth the crown must have a furcation flute.

39. Pontic design Pontic requirements: • Aesthetically acceptable • Restore function and occlusal stability. • Be designed to minimize plaque accumulation. • Provide embrasures for healthy papilla

40. The pontic material has no effect on the biologic tissue response provided that it has a smooth surface finish. • The amount of plaque accumulation around pontics made of glazed and unglazed porcelain, polished gold, and polished acrylic resin was found to be similar. • The health of the gingival tissues around fixed prosthesis depend on the pt’s oral hygiene. The pontic design should take this into consideration. • The pontic contact with ridge should be minimal and pressure-free.

41. The fitting surface of pontics • The pontic should obey the principles of crown contours with the addition of the fitting surface. • The fitting surface should be convex to allow proper oral hygiene. • Concavities should be avoided.

42. Ovate pontic • This design is getting more popular because it provides the best aesthetic result. • It requires surgery. • The fitting surface should be 1-1.5 mm subgingival and should be convex. • Requires careful treatment planning.

43. Saddle/ridge-lap • Has a concave fitting surface. • Least desirable design and should be avoided. • Has been associated with inflammation of the tissues due to it’s interference with plaque control.

44. Sanitary • The most hygienic. • Very poor aesthetics. • Need to clear the gingival tissues by 3 mm.

45. Conical • Conical/bullet/egg/heart • Poor aesthetics • Good access for oral hygiene • Suitable for lower posterior molars and lower anterior incisors.

46. Modified ridge-lap • The tip of the pontic barely contact the edentulous mucosa with the rest of the fitting surface is convex. • It combines the best aesthetics with the ease of cleaning. • The most recommended design

49. Multiple pontics

50. The same rules of contours and pontic design apply to Provisional restoration