Crowns

Crowns in Pediatric Dentistry

1. CROWNS IN PEDIATRIC DENTISTRY PRESENTED BY: ROSHNI MAURYA(18.2.2015) DEPT . OF PEDODONTICS & PREVENTIVE DENTISTRY

2. Introduction Although advances in the application of preventive dentistry techniques, widespread acceptance of community fluoridated water, and increased dental education in parents have reduced the incidence of caries in children, there is still a high prevalence of early childhood caries especially in the lower socioeconomic population . Aesthetic treatment of severely decayed primary teeth is one of the greatest challenges to pediatric dentists. In the last half century the emphasis on treatment of extensively decayed primary teeth shifted from extraction to restoration.

3. Early restorations consisted of placement of stainless steel bands or crowns on severely decayed teeth. While functional , they were unaesthetic and their use was limited to posterior teeth . Similarly, a higher esthetic standard is expected by parents for restoration of their children’s carious teeth. Thus the choice of full coverage restorations for primary teeth must provide an aesthetic appearance in addition to restoring function and durability.

4. This presentation will concentrate on aesthetic full coverage restorations for anterior primary teeth as well as posterior primary teeth.

5. Indications for Full Coverage Tooth with large interproximal lesions Tooth with hypoplastic defects Unaesthetic tooth due to discoloration Tooth that have undergone pulp therapy with significant loss of tooth structure Tooth with significant tooth structure loss due to trauma or caries Tooth with small carious lesions and with large areas of cervical discoloration

6. The types of full coverage for primary teeth currently available are: Stainless steel crowns Open faced steel crowns Polycarbonate crowns Resin (composite) strip crowns Pre-veneered steel crowns Recent development s for anterior crowns.

7. The crowns that are available for restoring primary teeth (Table 1) can be placed into 2 categories : those that are preformed and held onto the tooth by a luting cement, and those that are bonded to the tooth.

8. Waggoner ;Restoring primary anterior teeth Pediatric Dentistry – 24:5, 2002

9. Open Faced Stainless Steel Crowns With aesthetics of child’s smile of extreme importance to parents , many opted for extraction and prosthetic replacement of severely decayed teeth rather than placement of stainless steel crowns . Although, more durable and retentive than amalgam or composite stainless steel c rowns are unaesthetic, especially on the anterior teeth . The advent of composite bonding, allowed for a composite facing to be placed on the facial surface of the tooth , thus improving aesthetics.

10. Open faced stainless steel crowns combine strength, durability and improved aesthetics. However, they are time consuming to place as the composite facing cannot be placed until the stainless steel crown cement sets . Although this technique is a dramatic improvement over the plain metallic appearance of stainless steel, the procedure is time consuming and metal margins can still be seen.

11. Advantages The aesthetics are fair. (The metal shows through the composite facing). They are very durable, wear well and retentive . The materials are fairly inexpensive . Disadvantages The time for placement is long as it involves a two-step process (crown cementation / composite facing placement .) Placement of the composite facing may be compromised when gingival hemorrhage or moisture is present or when the patient exhibits less than ideal cooperation.

12. Open Faced Stainless Steel Crown Technique Once the cement is set, cut a labial window in the cemented crown using a no. 330 or no . 35 bur.

13. Extend the window : Just short of the incisal edge Gingivally to the height of the gingival crest Mesio-distally to the line angles Using a no. 35 bur remove the cement to a depth of 1mm. Place undercuts at each margin with a no . 35 bur or with a no . ½ round bur Smooth the cut margins of the crown with a fine green stone or white finishing stone.

14. After using a glass ionomer liner to mask differences in color between remaining tooth structure and cement place a layer of bonding agent. Place resin based composite into the cut window forcing the material into the undercuts and polymerize . Add additional material in 1mm increments and polymerize.

15. Finish the restoration with abrasive disks. Run the disks from the resin to the metal at the margins so as not to discolor the resin with metal particles Repeat the procedure for the remaining teeth .

16. Polycarbonate Crowns Polycarbonate crowns are heat-molded acrylic resin shells that are adapted to teeth with self cured acrylic resin. They were popular in the 1970’s, however, although they were more aesthetic than stainless steel crowns the polycarbonate material was: brittle and did not resist strong abrasive forces, exhibiting frequent fracture and dislodgement.

17. Advantages They are very aesthetic, with greater durability than composite strip crowns and pre-veneered crowns . They are not as technique sensitive as composite strip crowns as the fabricated crown is cemented with self adhesive resin cement rather than bonding. They take about the same amount of time to place as stainless steel crowns, composite strip crowns and preveneered crowns, and less than open faced stainless steel crowns. Disadvantages They are not recommended in patients that are heavy bruxers. Greater tooth reduction is required.

18. Polycarbonate Crowns Technique Reduce the incisal edge a minimum of 2mm. Reduce the labial surface & lingual surface a minimum of 2mm, finishing the preparation subgingivally .

19. For the interproximal reduction all contact must be broken. Remove all remaining decay and perform any necessary pulp tissue treatment . Completed tooth preparation . Select a crown that fits easily over the prepared tooth and has the appropriate mesiodistal dimension. If the crown does not seat without incisal interference additional tooth reduction is necessary .

20. Remove the ID Tab and tab connector with a scissor and sandpaper disc from the crown form .

21. Reseat the crown form onto the prepared tooth. All margins are subgingival. Check or estimate the occlusion. Adjust the margins and occlusion . Remove the crown from the tooth . Crimp all the gingival margins of the crown using a bull nosed crimping pliers.

22. Simply grab the margin with the pliers and bend the margin in. Continue around the circumference of the crown .

23. Cementation Immediately prior to cementation, thoroughly rinse the tooth with a high speed water spray. Once the tooth is clean place a gauze over the tooth with firm pressure on the gingival tissues to control any bleeding, as necessary while the crown is being loaded with self-adhesive resin cement. Apply GC Coat Plus (GC) to the internal surface of the crown using a brush or pledget . Dry the GC Coat Plus with a gentle air flow until bone dry and then light cure for 10 seconds . Fill the crown will self adhesive resin ( e.g. RelyX (3M ESPE, St. Paul, MN), SmartCem (Dentsply , York, PA) or G- Cem Automix ( GC America , Alsip, IL). Use a shade labeled Translucent or Light Seat the crown fully and completely. Maintain finger pressure on the crown and light cure the buccal and lingual margins for 2-3 seconds. Remove excess cement with an explorer and floss interproximately taking great care to stabilize the crown so that the position of the crown is not disturbed while the cement is setting . Light cure the crown for 20 seconds

24. Once the cement is set the occlusion is checked and adjusted .

25. Composite Strip Crowns Composite strip crowns are composite filled celluloid crowns forms . Composite strip crowns rely on dentin and enamel adhesion for retention. Therefore the lack of tooth structure, the presence of moisture or hemorrhage contributes to compromised retention. A 2002 study by Tate, et al . found that composite strip crowns had a failure rate of 51%, compared to an 8% failure rate of stainless steel crowns .

26. Advantages It provides superior aesthetics. The cost of materials are reasonable (approximately $6/crown). The time for placement is reasonable. Disadvantages It is extremely technique sensitive. It is not as durable or retentive as stainless steel/open faced crowns, pre-veneered crown or polycarbonate crown and is not recommended on patients with a bruxism habit or a deep bite. Adequate moisture control might be difficult on an uncooperative patient.

27. Composite Strip Crowns Technique Select a primary celluloid crown form with a mesio -distal incisal width equal to the tooth to be restored by placing the incisal edge of the crown against the incisal edge of the tooth . Remove decay with a medium to large round bur on a slow speed handpiece. If pulp therapy is required do it at this time.

28. Reduce the interproximal surfaces by 0.5 to 1.0 mm. The interproximal walls should be parallel and the gingival margin should have a feather edge . Reduce the facial surface by 1mm and the lingual surface by 0.5mm. Create a feather-edge gingival margin. Round all line angles . Trim the selected crown by removing the collar and the gingival excess material with crown and bridge scissors. Place a small vent hole on the mesial distal edge surface with a bur or explorer to allow escape of trapped air when the composite filled crown is seated .

29. Fit the crown on the prepared tooth. The crown should extend 1mm below the gingival margin. Maxillary lateral incisors are usually 0.5 to 1.0 mm shorter than central incisors . Select the appropriate shade of composite (extra light). Fill the crown with resin material approximately two thirds full.

30. Etch the tooth with acid gel for 15 seconds, wash and dry the tooth, and apply bonding agent . OR Use a self-etching bonding agent Polymerize Seat the filled crown form on the tooth. Remove the excess material from the vent hole and the gingiva. Repeat the procedure with the adjacent teeth. Polymerize the material from both the facial and lingual directions.

31. Repeat the procedure for adjacent teeth.

32. Remove the celluloid form by cutting the material on the lingual with either a composite finishing bur or scalpel. Pry the celluloid form off the tooth . Very little finishing is required except for adjusting the occlusion and smoothing gingival margins . Use flame shaped and rounded composite finishing burs for finishing.

33. Although the technique has been well described, surprisingly, very little clinical data exists on the longevity of these crowns . [ Webber DL, Epstein NB, Wong JW, Tsamtsouris A. A method of restoring primary anterior teeth with the aid of a celluloid crown form and composite resins. Pediatr Dent. 1979;1:244-246. Grosso FC. Primary anterior strip crowns J Pedodont . 1987;11:182-187. Croll TP. Bonded composite resin crowns for primary incisors : technique update. Quintessence Int. 1990;21:153-157 .] The procedure is very technique sensitive, and any lapses in patient selection , moisture and hemorrhage control, tooth preparation , adhesive application and resin composite placement can lead to failure . The difficulty in application is reflected in a study that only 21% of general dentists surveyed perform strip crowns compared to 73% of pediatric dentists. [ McKnight-Hanes C, Myers DR, Davis HC. Dentists’ perception of the variety of dental services provided for children . ASDC J Dent Child. 1994;61:282-284 .]

34. Pre-veneered Stainless Steel Crowns They were introduced in the mid 1990’s. They are aesthetic, placement and cementation are not significantly affected by hemorrhage and saliva and can be placed in a single appointment . The stainless steel crown is covered on its buccal or facial surface with a tooth colored coating of polyester/epoxy hybrid composition.

35. A clinical disadvantage is they are relatively inflexible as the resin facing is brittle and tends to fracture when subjected to heavy forces or crimping. Because only the lingual portion of the crown can be adjusted (crimped), significant removal of tooth structure must be performed to fit the tooth to the crown rather than the crown to the tooth . There is limited shade choice. They are more expensive to purchase than stainless steel crowns, strip crown forms and polycarbonate crowns (approximately 18 vs. 6 dollars ).

36. Advantages They are aesthetically pleasing. They require relatively short operating time. They have the durability of a steel crown. They are less moisture sensitive during placement than composite strip crowns . Disadvantages They are 3 times more expensive than stainless steel, strip and polycarbonate crowns The technique does not allow for major recontouring and reshaping of the crown. The tooth is adjusted to fit the crown, rather than adjusting the crown to fit the tooth. As crimping is limited to lingual surfaces there is not close adaptation of crown to tooth. There are reports of the veneer facing fracturing , however it can be easily repaired using the open faced stainless steel crown technique .

37. Pre-veneered Stainless Steel Crown Technique Size the crown to the tooth by placing the incisal edge of the crown against the incisal edge of the tooth. Prepare the tooth as for a standard stainless steel crown, however more circumferential tooth reduction required.

38. Refine the prep to fit the crown. Do not force the crown on the tooth. A properly fitted crown has a passive fit. The crown should extend 1mm past the gingival margin . The length of the crown is altered by trimming the gingival margin with a diamond bur and water spray.

39. The lingual aspect of the crown may be crimped slightly with a no. 137 Gordon plier. Too much crimping of the metal substructure may cause fractures in the veneer material . The crown is cemented with glass ionomer cement .

40. The excess cement is removed and the remainder is allowed to set . After cementation the incisal edges may be contoured with a finishing disk or point . If the veneer fractures a similar technique to the open-faced crown may be used for repair.

41. NUSMILE CROWNS Specially Formulated Hybrid Composite Substructure 2 Shades for Anterior Crowns(XL and NL); Posterior Crowns(XL only) Centrals and Laterals sizes 1-6, Cuspids Sizes 0-6, 1st & 2nd Primary Molars Sizes 1-7 Waggoner and Cohen [1995] reported Cheng Crowns , Kinder Crowns , NuSmile Primary Crowns have resin composite facings whereas Whiter Biter Crown II has a flexible thermoplastic veneer( exhibiting greatest shear force and retention compared to other brands).

42. Advantages: Single appointment Easy placement technique Reduces operatory time Less technique sensitive Disadvantages: More tooth preparation due to their greater bulk . Avoid crimping - facing susceptible to fracture, so the tooth is prepared to fit the most appropriate crown. Single-use only-sterilization is recommended

43. Selecting a Crown Very short clinical crowns and crowded dentitions may not be ideal for beginning case selections. Preparation of the Tooth crown fits the tooth passively: flexing of metal substructure from pressure during fitting or seating can cause micro-fractures

44. NUSMILE CROWNS Anterior teeth Reduce the incisal length of the tooth by approximately 2mm and open the interproximal contacts . feather-edge margin tapered diamond burs : proceed from coarse to fine as the preparation is completed. NUSMILE CROWNS Posterior teeth The tooth should be reduced by approx 30% More preparation : buccal and occlusal aspects (at least 2mm) Crimping not necessary Do not crimp excessively or near the facing Minimally on lingual aspect of crown  

45. CHENG CROWNS Peter Cheng Orthodontic Laboratory-1987 anterior crowns faced with a high quality composite (mesh-based with a light cured composite.) Advantages: completed in one patient visit (and with less patient discomfort) natural looking stain resistant doesn’t cause wear of opposing teeth Disadvantages: fracture of veneers during crimping expensive .

46. Anterior Crowns Centrals : left & right sizes (1-6) Laterals : left & right sizes (1-6 ) Cuspids: upper & lower sizes (1-6) Posterior Crowns First primary molar: upper and lower - left and right sizes (2-7) Second primary molar :upper and lower - left and right sizes (2-7 )

47. PEDO PEARLS Heavy gauge aluminum crowns coated with FDA food grade powder coating and epoxy-resin. ADVANTAGES: Universal anatomy-use on either side Easy to cut and crimp, without chipping or peeling. Non bulky & fits easily DISADVANTAGES: less durability and the crowns are relatively soft self-cured or dual-cured composite is recommended for repairing

48. DURA CROWNS White-Faced Crowns Crowns can be crimped labially and lingually, can be easily trimmed with crown scissors, easily festooned and has got a full-knife edge. Starter Kit includes: 24 Crowns. Centrals , left and right sizes 2,3,4 two of each. Laterals , left and right sizes 3,4,5 two of each

49. KINDER KROWNS 1988 by pediatric dentists natural shades and contour available Great depth and vitality from the lifelike composite Available in 2 shades; PEDO 1 & PRDO 2

50. PEDO CHEMPU CROWNS Sizes 2-4 Color : White Color stable, plaque resistant, match natural pediatric shades. Available for the right and left central and lateral as well as cuspids. Kit includes -centrals, left and right sizes 2,3,4 (2 of each) – laterals , left and right sizes 2,3,4 (2 of each)

51. PEDO JACKET It is a tooth colored copolyester material which is filled with resin and left on tooth after polymerization instead of being removed. ADVANTAGES : It does not split, stain or crack. Crowns can be easily trimmed with scissors. Thin yet strong interproximal wall allows multiple adjacent restorations with a minimum amount of tooth reduction.  Using a plastic primer, they can either be bonded into place with composite resin or cemented with a glass ionomer cement. DISADVANTAGES:   Only one size is available

52. NEW MILLENIUM CROWNS This is similar in form to the pedo jacket and strip crown, except that it is lab enhanced composite resin material . Like others, this is also filled with resin material and bonded to the tooth

53. ARTGLASS CROWNS Multi-functional methacrylate matrix – 3 D molecular networks with a highly cross-linked structure. 75% filler (55% microglass and 20% silicafiller) Available in 6 sizes for every primary tooth and every Vita shade

54. Advantages One appointment placement Provide greater durability and esthetics than strip crowns. Easily adjusted or repaired intraorally Color stable Wear of polymer glass similar to enamel, kind to opposing dentition- feels natural to the patient.

55. Seating instructions : Preparation similar to S.S.C with more reduction Fits passively Place artglass liquid for 1 min inside crown Then place flowable composite in crown and then place on tooth Finish with carbide bur.

56. Updyke studied 95 Artglass crowns that he placed in a 2-year period . Of 95 crowns, 79 received Alfa ( representing clinically ideal), 11 received Bravo ( representing clinically acceptable ), and 5 received Charlie ( representing clinically unacceptable) ratings. The vast majority of the failures were due to bond failures. The difficulty in interpreting this data is the absence of an independent observer and the fact that the dentin adhesive was changed to a different product during the study. Nevertheless , this study format illustrates how a clinician can initiate a pilot study in evaluating his or her own procedures to establish a more substantive investigation . [ Updyke JR. Esthetics and longevity of anterior artglass crowns . J Southeastern Soc Pediatr Dent. 2000;6:25-26] .

57. Conclusion Many options exist to repair carious primary teeth, but there is insufficient controlled, clinical data to suggest that one type of restoration is superior to another. This does not discount the fact that dentists have been using many of these crowns for years with much success . Operator preferences, esthetic demands by parents, the child’s behavior, and moisture and hemorrhage control are all variables which affect the decision and ultimate outcome of whatever restorative treatment is chosen . ( Pediatr Dent . 2002;24:511-516)

58. Crowns remain the best restoration in many cases, and esthetic crowns will have a larger role in pediatric dentistry if improvements are made to reduce the bulk, lessen the thickness of the veneer, improve the bonding between the metal and the esthetic facing, and reduce the cost. These techniques are relatively new and need to pass the test of long-term clinical use . With all full coverage restorations parents must be advised to institute appropriate preventive health practices (elimination of sugar containing drinks, regular tooth brushing and topical fluoride application) to maximize gingival health and minimize the recurrence of caries under the restorations.

59. Table1:Summarizes the properties and selection criteria of various full coverage techniques currently available to practitioners.

60. Thank u