Coronoplasty

The most important 9 steps to remove trauma from occlusion and also splinting to last for years.

1. CORONOPLASTY Presented by- Dr Jharna Bharali Post Graduate Trainee Dept Of Periodontology

2. TFO?

3. Introduction When occlusal forces exceed the adaptive capacity of the tissues, tissue injury results. The resultant injury is termed as Trauma From Occlusion. ( Carranza 10 th Edition) Adaptive or pathologic changes that develop in the periodontium as a result of abnormal masticatory forces are called Trauma From Occlusion. ( Verma & Nayak )

4. The masticatory forces are transmitted to the alveolar bone through the periodontal ligament in an axial direction. The periodontium has the capacity to withstand slight variations of masticatory forces known as the Physiologic Adaptive Capacity. Horizontal and rotational forces tend to produce areas of pressure and tension in the alveolar bone resulting in bone resorption in the pressure zones.

5. Factors involved in the creation and distribution of forces of occlusion are as follows: The forces of muscles of mastication and the counteracting oral musculature. Retrusive occlusal forces Posterior lateral forces Protrusive occlusal forces

6. Anterior component of occlusal forces tend to move teeth mesially within the socket. Original position due to the presence of the periodontal ligament Proximal contact areas become flat due to attrition.

7. 3. Proximal contacts permit the transmission of anterior component of forces. Absence of contact and malpositioned contact produce abnormal forces leading to the displacement of teeth

8. 4. Morphologic alignment and inclination of the teeth affect the transmission of occlusal forces. Maxillary central incisors are inclined anteromesially to provide maximum efficiency of their incisal edge. Roots of maxillary central incisors have greater periodontal attachment distally and palatally . Molars are inclined mesially so as to transmit the mesial component of occlusal forces to premolars and canines. Cuspal inclinations determine the magnitude of force.

9. 5. Direction of occlusal contacts affects the force. 90 ° Abnormal occlusal contact may generate an oblique force which is detrimental to the periodontium

10. 6 . Atmospheric equilibrium during breathing and swallowing contributes to the occlusal forces. Occlusal Forces

11. PLUNGER CUSP

12. Plunger Cusp Cusp that tend to forcibly wedge food into the interproximal region of the opposing teeth. The plunger cusp effect of occlusal interference may produce a functional opening of contact between the teeth, leading to food impaction. These plunger cusp are usually the functional cusp and sometimes palatal incline of maxillary buccal cusp and buccal incline of lingual cusp .

13. CORONOPLASTY

14. CORONOPLASTY The mechanical elimination of occlusal supracontacts that may be present during functional movement. Achieved by- Reshaping the crown surfaces. Eliminating undesirable occlusal supracontacts. Creation of stable mandibular position.

15. Occlusal Adjustment : Defined as the establishment of functional relationships favourable to the periodontium by- Reshaping teeth by grinding Tooth movement Restorations Extractions Orthognathic surgery

16. Objectives To eliminate mechanically all occlusal supracontacts in function and parafunction which result in: Change in pattern and degree of afferent impulses. Reduced mobility. Multiple uniform occlusal contacts. Beneficial change in the pattern of chewing and swallowing. Multidirectional mandibular movement patterns. Verticalisation of occlusal forces on implants.

17. Indications: Improvement of functional relations between teeth. Elimination of traumatic occlusion, abnormal muscle function, bruxism and TMJ discomfort. Establishment of optimal occlusion before extensive restorative procedures. Preventive occlusal adjustment.

18. Discussion Coronoplasty may be considered only in patients with evidence of trauma from occlusion. Coronoplasty is generally performed after the gingival inflammation and periodontal pockets have been eliminated. When infra bony defects associated with TFO are being treated, coronoplasty has to be performed prior to or at the time of pocket elimination.

19. In cases of excessive tooth mobility associated with TFO, coronoplasty is advocated prior to or during periodontal therapy. Since the occlusal forces affect the post treatment contour of the facial alveolar bone, coronoplasty is indicated prior to mucogingival surgical procedures. Coronoplasty is also indicated prior to other treatment procedures when a cracked tooth is suspected.

20. Ideally the end point of occlusion is the retruded contact position (RCP). Intercuspal position (ICP) is the functional end point of occlusion with maximal bilateral intercuspal contact relationship. Instability at ICP causes- Reflex inhibition of the elevator muscles. Promotes increased neuromuscular control on mandibular positioning. ( Gibbs & Lundeen in 1982 ) ICP is generally accepted as the end point of coronoplasty.

21. Bilateral Balanced Occlusion According to this concept, the occlusal forces are proportionately distributed to all teeth. In lateral excursions, both functional and non functional sides are adjusted to produce bilateral contacts.

22. Group Function Occlusion According to this concept, the buccal slopes of mandibular buccal cusps and the lingual slopes of maxillary buccal cusps are adjusted so that the load is equally distributed among these cusps at all times during the lateral movements. Non functional side Functional side

23. Canine Protected Occlusion According to this concept, maxillary and mandibular canines bear the occlusal forces during lateral excursions. Canines are capable of withstanding such heavy load. Mutually protected occlusion with lateral canine guidance

24. Method Of Coronoplasty Coronoplasty can be done on the mounted casts and the sequence of grinding may be recorded. Articulating paper, mylar strips and wax templets are used to locate premature contacts. Vibrations of the teeth due to premature contacts can be detected by keeping wet finger on the facial aspect of the maxillary teeth and asking the patient to bring the teeth into occlusion.

25. Corrections of supra contacts Grooving : Procedure adopted to restore the depth of developmental grooves. Pointing: Procedure adopted to restore the cusps to normal. Cusps are reshaped to the normal pointed contour. Spheroiding: Reducing supra contact and restoring the original contour of the tooth. Recontouring : Done from the occlusal margin to a distance 2-3mm apical to the marking.

26. Grooving Pointing

27. Spheroiding

28. Steps of Coronoplasty Coronoplasty can be performed in nine sequential steps. The whole procedure is completed in a few appointments, each visit lasting for 30 minutes. Patients co-operation is essential to achieve good results. Hence the whole procedure is explained to the patient before starting the procedure.

29. SN . STEPS 1. Remove retrusive prematurities and eliminate the deflective shift from RCP to ICP. 2. Adjust ICP to achieve stable , simultaneous multi-pointed widely distributed contacts. 3. Test for excessive contact (Fremitus) on anterior teeth. 4. Remove posterior protrusive supra contacts and establish contacts that are bilaterally distributed on the anterior teeth. 5. Remove or lessen mediotrusive interference. 6. Reduce excessive cusp steepness on laterotrusive contacts. 7. Eliminate gross occlusal disharmonies. 8. Recheck tooth contact relationship. 9. Polish all rough tooth surfaces.

30. 1 . Remove retrusive prematurities and eliminate the deflective shift from RCP to ICP. Reduce supracontacts that interfere with posterior border closure of the mandible to a stable bilateral RCP When contact is located on the retruded path of closure, supracontacts may cause the mandible to deflect forward and sometimes laterally into the ICP. This contact movement is termed the shift or slide from RCP to ICP Retrusive adjustment results in the elimination of the RCP-to-ICP shift

31. Horizontal Tracing Proximal View Shift from retruded contact position (RCP) to intercuspal position (ICP). Before occlusal adjustment . Mandibular teeth shift from point 1 to 2 (asymmetric shift). The same movement is seen in the arrow point tracing in the horizontal plane. After occlusal adjustment. Asymmetric shift from RCP to ICP is removed, and resulting intercuspal position is nearer or identical to RCP.

32. Methods for locating contact positions: Patient is supine. Forefinger and thumb positioned against the chin with other hand stabilizing it. Dawson’s Method Techniques for retrusive coronoplasty : Chin grasp technique Dawson’s method A B B A

33. Remove the inclines between RCP and ICP that cause supracontacts when the mandible moves from RCP to ICP, without removing the vertical stop or supporting cusp tip These inclines, called retrusive prematurities , are usually found on mesial facing inclines of the maxillary teeth and distal facing inclines of the mandibular teeth. Preserve marginal ridges, adjust cusp tip as last resort.

34. The retrusive range adjustment is complete when the following conditions are achieved: The contact pattern is bilateral with multi-pointed contacts; The deflective shift from RCP to ICP has been eliminated Both RCP and ICP approach the same vertical dimension of occlusion. The pathway from RCP to ICP, if present, is smooth and gliding. Repeated closure of the teeth together in the hinge position produces a sharp resonant soun d.

35. 2. Adjust ICP to achieve stable , simultaneous multi-pointed widely distributed contacts. Achieve a stable ICP and to refine occlusal anatomic relationships The main feature is that supracontacts are identified without guidance by the operator's hand The alteration that commonly are made in conjunction with this step are : Reduction of cuspal size Alteration of occlusal table width Lessening of plunger cusp heigh t

36. Normal Zones of contact in the intercuspal position. Open circles denotes vertical (centric) stop; Solid circles denote centric cusps. Zones of contact in a natural dentition.

37. Class I prematurities in the intercuspal position. Class I prematurities on the facial surface of the mandibular anterior and posterior teeth are indicated by arrows.

38. 3. Test for excessive contact (Fremitus) on anterior teeth The incisor tooth should be slightly out of contact or in light contact over the maximum number of teeth. The mylar strip should just slip through the incisor teeth in ICP. No fremitus should be detectable.

39. The ICP adjustment is complete when: The contact pattern is bilateral, stable and many pointed. Each posterior vertical step holds a Mylar occlusal strip with equal resistance. Sharp, resonant sounds are heard when the patient taps his or her teeth together in ICP (with a stethoscope placed over the infraorbital skin area.) The patient responds negatively to the following question: 'Tap on your back teeth, slow and hard— Do you feel any difference between the two sides?.” No fremitus is detected in the anterior teeth.

40. 4. Remove posterior protrusive supra contacts and establish contacts that are bilaterally distributed on the anterior teeth. Correction of the anterior teeth in protrusive position.

41. 5. Remove or lessen mediotrusive interference. Adjustment of mediotrusive (Balancing) interference often involves grooving to allow freedom for the opposing cusp movement.

42. 6. Reduce excessive cusp steepness on laterotrusive contacts . Correction of laterotrusive interferences (notched areas) on posterior teeth to gain smooth contact movement patterns, mandibular movement indicated by arrows. Laterotrusive Side Prematurity Mediotrusive Side Laterotrusive Side

43. 7. Eliminate gross occlusal disharmonies. Class III prematurity in the intercuspal position, the buccal surface of the lingual cusp of the maxillary molars and premolars with the lingual aspect of the buccal cusps of the mandibular teeth (Arrows) Plunger cusp on the maxilla. The premolar forces the food between the mandibular teeth causing gingival inflammation.

44. Reshaping slightly rotated tooth by grinding . Slightly rotated molar. Areas to be removed by grinding are indicated by dashed lines. Occlusal surface recontoured (dashed lines) and buccal grooves relocated.

45. 8. Recheck tooth contact relationship . Tooth contact relationships in all positions are checked along with the movements. 9. Polish all rough tooth surfaces .

46. Criteria For Judging The Outcome Of Coronoplasty There is no asymmetric shift from RCP to ICP. If a shift is present, it is smooth, symmetric, and less than 1 mm in magnitude . The completed adjustments have light contact or no contact between the incisor teeth and firm contact between as many posterior teeth as possible . The patient perceives "even" (bilateral) contact when closing the teeth to ICP. Sharp occlusal sounds are produced when the patient taps slowly and firmly into ICP. Molar excursive supracontacts are neutralized or significantly reduced so that unrestricted glide paths are available for the posterior cusps Tooth guidance under lateral and protrusive excursion is smooth and without effort. The displacement of mobile teeth is minimized under closure and gliding movements .

47. Jankelsons Method Of Occlusal Adjustment Relationship of the teeth in centric occlusion is taken into consideration and not the excursive movements. Emphasis is placed on the cusp to fossa relationship of teeth in terminal hinge occlusion. According to this concept, the masticatory forces are transmitted to the teeth during the final hinge closure and the prematurities need be corrected only at this place.

48. Types: Type I: Buccal surfaces of mandibular teeth are in premature contact with the buccal cusps of the upper teeth. The same relationship exists in the anterior teeth also. Type II: Lingual surfaces of the maxillary posterior teeth are in premature contact with the lingual cusps of mandibular teeth. Type III: Lingual cusps of the maxillary teeth are in premature contact with the buccal cusps of mandibular teeth.

49. Conclusion Measurement of the outcomes from occlusal therapy usually cannot be readily achieved. In cases where patient is experiencing discomfort from occlusal contact, patient will experience relief from pain when they are relieved from occlusal forces. In most cases , however, the changes can only be measured in terms of decreased mobility and long term results to periodontal therapy.

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