1. Charles J. Goodacre, DDS, MSD
Professor of Restorative Dentistry
Loma Linda University School of Dentistry
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Optimizing success
with resin bonded prostheses

2. • Rochette
• Acid Etched
• Resin Retained
Resin bonded prostheses names
• Etched Cast
• Maryland
• Virginia

3. Resin Bonded Prosthesis Success
• Diagnosis & Treatment Planning
• Tooth Preparation
• Design, thickness, fit
• Cementation (Bonding)

4. RBP Complications
Incidence
• 48 studies
• 1823 of 7029
prostheses had
complications
• Mean of 26%
• 1-4 years (25%)
• 5+ years (28%)

5. Most Common RBP
Complications
• Debonding (21%)
• Tooth discoloration (18%)
• Caries (7%)
• Porcelain fracture (3%)
• Periodontal health (N.S.)

6. RBP Debonding
(Evaluated in 49 Studies)
• 1481 of 7029 prostheses debonded
• Mean of 21%
• Range from 0.0 to 52%

7. Systematic Review
of RBP
• Review included 17 publications
• 19% debond rate after 5 years
• Annual debond rate of 5% on posterior
teeth versus 3% on anterior teeth
Pjetursson, Clin Oral Imp Res 2008;19:141-141

8. Debond Rates Over Time
• Initially a higher debond rate
• Then a decrease up to 5 years
• Increased rate after 5 years
• “Wearin” for the first 5 years
• “Wearout” after 5 years
Boyer, 1993

9. Debonding should not be considered a
failure since rebonding does not
constitute significant investment or
inconvenience to patients or dentists
Priest, 1988
Do you agree?

10. RBP Span Length
(Evaluated in 8 Studies)
• Mean debond rate of 25% with short
spans
• Mean debond rate of 52% when more
than 3 units, more than 1 pontic or
prostheses with more than 2 retainers

11. Span Length & Debonding
• Increased debonding with multiple
pontics
Dunne, 1993
Mudassir, 1995
• Increased debonding with 4 or more
units
Probster, 1997

13. Toooo Wide

14. Occlusal Forces
(Evaluted in 7 Studies)
• In 2 studies, 70% and 45% of
debonding caused by heavy occlusal
forces
• In 5 studies, 22% (31 of 143 debonds)
of debonds caused by heavy occlusal
forces

17. Maxillary/Mandibular Debond
Rates (Evaluated in 27 Studies)
• á in maxilla (6 studies)
• á in mandible (8 studies)
• No significant difference in 13 studies
• No conclusive trend

18. Anterior / Posterior Debond
Rates (Evaluated in 23 Studies)
• á Anteriorly in 4 studies
• á Posteriorly in 8 studies
• No significant difference in 11 studies
• No conclusive trend

19. Affect of Gender on Debonding
(Evaluated in 8 Studies)
• No significant difference in 5 studies
• Higher male debond rate in 3 studies
• Possible male trend

20. Affect of Age on Debonding
(Evaluated in 6 Studies)
• Higher debond rate in young patients in
4 studies
• No significant difference in 2 studies
• Possible age trend

21. Affect of Incisally
Positioned Gingiva
Produces Short
Clinical Crowns

22. RBP Abutment Tooth Discoloration
(Evaluated in 7 Studies)
• 62 of 343 prostheses affected
• Mean of 18%
• Range from 3 to 37%
• Increases with time

23. Tooth Discoloration
• 21% had incisal discoloration
Williams, 1984
• 37% concerned with shade / color
Thayer, 1993
• 13% had gray abutments
Gilmour, 1995

24. Tooth Discoloration
• Increases with time
4% after 7 years
25% after 10 years
37% after 15 years
Thayer, 1993

25. The lingual metal produces discoloration, particularly
through translucent portions of the abutment teeth

27. RBP Caries
(Evaluated in 22 Studies)
• 242 of 3426 prostheses had caries
• Mean of 7%
• Range from 0.0 to 12%
• None in 9 studies (2 mos. - 59 mos.)
• < 2% in 6 studies (2 mos. - 5 yrs. 8 mos.)
• 2.5 - 12% in 7 studies ( 2.5 - 10 yrs.)
• Most associated with debonding

29. RBP Porcelain Fracture
(Evaluated in 15 Studies)
• 38 of 1126 prostheses affected
• Mean of 3%
• Range from 0.0 to 8%

30. RBP and Periodontal Health
(Evaluated in 14 Studies)
• No problems noted in 6 studies
• Mild, nonsignificant changes in 4
studies
• Significant but not clinically relevant
changes in 4 studies

31. All resin bonded prostheses are overcontourted. The reason
there is not more of a negative affect is that the overcontouring
is usually located incisal to the gingival margin.

32. Cantilever Designs
• 54 cantilever prostheses in 47 patients
• 27 months mean postplacement time
• 11 prostheses debonded (20%)
• 8 of 11 were successfully rebonded
Briggs, 1996

33. Cantilever Designs
• Did not affect survival
Leempoel, 1995
• Lower debond rate
associated with
cantilever design
Hussey, 1991

34. Cantilever Success Data
• 32% debond rate
when the maxillary
central incisor was
cantilevered from the
central incisor or the
lateral incisor
(28 prostheses)
Hussey, 1996

35. Cantilever Success Data
• 3 year mean postplacement time
• 12% overall debond rate
• 24% debond rate when the maxillary
canine was cantilevered from the first
premolar (17 prostheses)
Hussey, 1996

36. Cantilever Success Data
• 6% debond rate when
the maxillary lateral
incisor was cantilevered
from the canine
(63 prostheses)
Hussey, 1996

37. • 6% debond rate when
the maxillary lateral
incisor was cantilevered
from the canine
(63 prostheses)
Hussey, 1996

38. Cantilever Designs Have Been Successfully
Used since 1988 by Dr. John Locke,
Prosthodontist in Melbourne, Australia

39. Cantilever Success Data
• No debonds when
a maxillary
premolar was
cantilevered from
the other premolar
(8 prostheses)
Hussey, 1996

40. Cantilever Success Data
• No debonds with
26 mandibular
prostheses
Hussey, 1996

41. Cantilever with Splinted Retainers due to
Orthodontic Rotation of Maxillary Canine

42. Other DxTP Considerations
• Intact / minimally restored abutments

43. Other DxTP Considerations
• Intact / minimally restored abutments
• Normal MD space

45. Other DxTP Considerations
• Intact / minimally restored abutments
• Normal MD space
• Normal contours

48. Other DxTP Considerations
• Intact / minimally restored abutments
• Normal MD space
• Normal contours
• Avoid splinting

49. Avoid Splinting & Multiple
Adjoining Retainers
• The number of retainers and splinting increases
the debond rate
Marinello, 1987
Olin, 1990
Dunne, 1993

50. Other DxTP Considerations
• Intact / minimally restored abutments
• Normal MD space
• Normal contours
• Avoid splinting
• Avoid mobile abutments

51. Debonding & Mobility
• Mobility causes some of the debonds
Ferrari, 1989
• Mobility increased the debond rate
Probster, 1997

52. Other DxTP Considerations
• Intact / minimally restored abutments
• Normal MD space
• Normal contours
• Avoid splinting
• Avoid mobile abutments
• Minimal translucency

53. Resin Bonded Prosthesis Success
• Diagnosis & Treatment
Planning
• Tooth Preparation
• Design, thickness, fit
• Cementation (Bonding)

54. Resin bonded prostheses were originally
introduced by Rochette as a prosthesis requiring
little or no tooth preparation. However, most of
the clinical studies that evaluated the effects of
tooth preparation indicate it decreases the
incidence of debonding and therefore increases
prosthesis longevity

55. Effect of Tooth Preparation
(Evaluated in 9 Studies)
• No significant effect in 3 studies
• Significant debonding in 5 studies
– 11% debond when prepared
– 47% debond with no preparation

56. 1. Cover Maximal Enamel Area
Need Teeth With Adequate
Enamel Surface Area

57. Effect of Bonding Area
• The area available for bonding affects success
Thayer, 1993
Priest, 1995
Ferrari, 1998
• The mean area of debonded retainers was 38
mm2 compared to retainers that did not debond
(45 mm2)
Thayer, 1993
• Age and gingival position affected the area
available for bonding

58. Prosthesis failure due
to minimal coverage
More appropriate area
covered

59. When the gingival tissue covers the cingulum, it
should be surgically removed prior to placement of a
resin bonded prosthesis so the maximal amount of
tooth structure is available for coverage.

60. 2. Cover the lingual and proximal
surfaces of each abutment

61. 3. Prepare the proximal surfaces so
they are convex faciolingually.

62. 4. Create adequate occlusal clearance
so the metal casting can possess
adequate rigidity (0.5 millimeter
minimum). In situations where there is
tight interdigitation of opposing teeth, it
may be necessary to modify opposing
enamel surfaces to create sufficient
clearance.

63. 0.5 mm minimum
4. Create adequate reduction of the occluding
surface so there is sufficient material thickness.

64. 5. Form a perpheral finish line (0.2 - 0.3 mm) that
provides positional stabiliy, increases casting rigidity,
and decreases overcontouring.

65. • Because the cervical enamel thickness on
mandibular incisors is minimal (0.1 – 0.3 mm),
placement of a chamfer finish line is not
recommended because it may remove all the
cervical enamel and adversely affect the bond.

66. Ledge
6. Form lingual ledges or occlusal rests seats
that provide positional stability, increased
resistance form and increased metal rigidity.

67. Posterior Tooth Preparations
• 180° axial coverage
Creugers, 1989
Crispin, 1991

68. Posterior Tooth Preparations
• Tooth preparation
should include multiple
rests
Barrack, 1993
• Tooth preparation can
cover the entire lingual
cusp with proximal
grooves

69. Rest seats should
resemble the tip of a
spoon, having greater
faciolingual dimension at
the marginal ridge and
taper toward the center
of the tooth. They
should extend about
1/3rd of the distance
across the occlusal
surface.

70. 0.5
mm
The rest seat depth should provide for at least 0.5 mm
of occlusocervical metal thickness at the marginal
ridge of the rest seat..

71. The cervical floor of the rest seat should slope apically
from the marginal ridge toward the center of the tooth
just like a rest seat in a crown for a removable partial
denture.

72. Grooves
7. Form proximal grooves that provide resistance form,
positional stability, and increased casting rigidity.

73. Proximal Grooves
• The use of proximal grooves
decreases debonding
Simon, 1992
Rammelsberg, 1993
Besimo, 1993
Barrack, 1993
• Use a number 700 bur and place
proximal grooves to an apical
depth that equals one-half the
diameter of the bur tip

75. • Pinholes can also be used and they are prepared
by first drilling a hole using a number ½ round bur
to the desired depth of 1.5 to 2.0 mm and then
using a number 700 bur to create the slightly
tapered form

76. Proximal Groove combined with
Lingual Groove(s)
• One proximal groove
• One or two lingual
grooves
(channels / furrows) that
are 1 mm deep
• ½ round bur to penetrate
enamel and then 168 bur
to refine lingual furrows
•
Technique developed by Dr. John Locke,
Prosthodontist, Melbourne, Australia
Courtesy of J Locke

77. Maxillary
Canine

78. Maxillary Central Incisor

79. Mandibular Incisor

80. Courtesy of J Locke

81. Courtesy of J Locke

82. Key Tooth Preparation Features
• Cover maximal area
• Cover lingual and proximal
• Convex proximal surfaces
• Adequate occlusal clearance
• Peripheral finish line
• Ledges / rests
• Multiple grooves or single groove with slot(s)
• Pinholes can be used
All These Features Produce A Definite Path
Of Placement & Resistance To Dislodgement

83. • Chamfer finish line – 0.2 - 0.3 mm deep
• Proximal grooves – apical depth of ½ the
tip diameter of a number 700 bur
• Reduction for occlusal clearance –
0.5 mm minimal clearance
• Lingual ledges (ant. teeth) –
0.2-0.5 mm deep
• Occlusal rests (posterior teeth) – 0.5 mm
minimal thickness at the marginal ridge,
extend 1/3 of the MD dimension of the
occlusal surface, and slope apically toward
the tooth center
• Pinholes (1.5 – 2.0 mm deep) can be used
Key Tooth Preparation Features

84. Resin Bonded Prosthesis
Success
• Diagnosis & Treatment
Planning
• Tooth Preparation
• Design, thickness, fit
• Cementation (Bonding)

85. Metal Thickness & Fit
• The space created for occlusal
clearance should be at least 0.5 mm
• Metal thickness over marginal ridges
should be 1.0 mm or more
• The internal adaptation need to be
excellent so the retentive features can
engage tooth structure

87. Resin – Metal Retention
• Macroscopic retention perforations

88. Resin – Metal Retention
• Macroscopic retention
Perforations
Meshes

89. Resin – Metal Retention
• Macroscopic retention
Perforations
Meshes
Internal undercuts
Salt crystal technique
Virginia bridge

90. 150 – 250 micrometer
salt crystals produced the
highest bond strengths
Moon, 1987

91. Resin – Metal Retention
• Macroscopic retention
Perforations
Meshes
Internal undercuts
• Microscopic retention
Electrolytic etching

92. Resin – Metal Bond
• Electrochemical etch is best
LaBarre, 1984
Brantley, 1986
Creugers, 1986

93. Resin – Metal Retention
• Macroscopic retention
Perforations
Meshes
Internal undercuts
• Microscopic retention
Electrolytic etching
Chemical etching
Electrolytically and
chemically etched bond
strengths were the
same. Three chemical
etchants were equally
effective
Aquilino, 1990

94. Resin – Metal Retention
• Macroscopic retention
Perforations
Meshes
Internal undercuts
• Microscopic retention
Electrolytic etching
Chemical etching
Airborne particle
abrasion
Airborne particle abrasion
and electrochemically
etched surfaces were the
same
Atta, 1986
Covington, 1987

95. Resin – Metal Bond Consensus
• Method of metal treatment is not critical
• The enamel – resin bond is the weak link
Shaw, 1982
LaBarre, 1984
Aksu, 1982
Holland, 1984

96. Resin Bonded Prosthesis
Success
• Diagnosis & Treatment
Planning
• Tooth Preparation
• Design, thickness, fit
• Cementation (Bonding)

97. Cementation (Bonding)
• Meticulous isolation and attention to
detail is required
Crispin, 1986

98. Cementation (Bonding)
• The usual enamel etching is performed
and visually verified.

99. Cementation (Bonding)
• If the etched enamel
becomes
contaminated
by saliva, the
surface should
be re-etched
since only drying
caused decreased
bond strengths
Hormati, 1980

100. Cementation (Bonding)
• If the etched metal surface
becomes contaminated by
saliva, it can be dried
since research
has shown that
drying has no
harmful effect
on bond strength
Ballesteros, 1986
Cassidy, 1987

101. Select A Chemically Polymerized
Resin Cement

102. Cementation (Bonding)
• Follow the
manufacturer’s
instructions
regarding
bonding
procedures.

103. Cementation (Bonding)
• Remove the
excess resin
before it
polymerizes,
particularly the
interproximal
excess

104. Cementation (Bonding)
• 32% of the
prostheses
exhibited excess
resin
gingivally
Thayer, 1993

105. Cementation (Bonding)
• Finishing / polishing the metal for 30
seconds with a bur and 20 seconds with
a brown rubber cup significantly
decreased the bond strength
• Most finishing should be completed
prior to bonding
Caughman, 1988

106. Rebonding Prostheses
• Remove existing resin using airborne
particle abrasion with 50 micrometer
aluminous oxide particles
• Rebonded prostheses have a higher
debond rate
Kerschbaum, 1996

107. Believe in “good luck”, but also believe it happens
most often to those who work hard and keep their
eyes open.
Thank You
Charles J. Goodacre, DDS, MSD
Professor of Restorative Dentistry
Loma Linda University School of Dentistry

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