Clinical evaluation of two posterior composite resins retained with bonding agents

Clinical evaluation of two posterior with bonding agents Hideaki Shiitani, D.D.S., D.D.Sc.,* Naoki Junko Satou, D.D.S.*** Hiroshima

University,

School of Dentistry, Hiroshima,

composite

Satou, D.D.S., D.D.Sc.,**

resins

retained

and

Japan

Two hundred thirteen carious cavities were restored with two brands of chemically adhesive posterior composite resins by totally etching both the enamel and dentin walls after removing only the caries detector-stainable tissue and with no mechanical retention form in the cavity preparation. Most cavities were extensive, involving more than two surfaces in 74%. The dentin floor was not covered with cement although a spot lining was placed when the cavity was deep. All restorations were examined, usually after 4 years, by photographs and scanning electron microscope observation of replicas, and by criteria established by the U.S. Public Health Service. The materials and the technique proved to be clinically useful. (J PROSTRET

D~~~1989;62:627-32.)

V

arious composite resins have recently been introduced for restoring posterior teeth. Investigators who have tested some posterior composite resins have been reluctant to recommend them.l-‘j The physical properties of the early posterior composite resins were inferior to those of amalgam.7,8 The more recent composite resins have been much improved.g The development of chemically adhesive bonding agents added a unique feature to the modern composite resins.lOvi1 The bonding agent, offering retention and pulp protection by a single application, permitted simplifed cavity preparation and restoration.12 This report on a 4-year clinical trial of two posterior composite resins inserted by the same simplified technique indicates acceptance of the method for restoring posterior teeth.

MATERIAL

AND

METHODS

The patients, in the age range of the twenties to the iifties, were employees who visited the factory dental clinic and agreed to cooperate. The first group of 41 patients (36 men and five women) had a group total of 106 posterior teeth that met the requirements for the study (Table I). Of those, 84 had large carious lesions or extensive amalgam restorations with recurrent caries. The remaining 22 teeth had narrow fissure caries. Only those teeth with opposing occlusion were included in the study population. The teeth were restored with Clearfil Posterior (Kuraray Co., Osaka, Japan) composite resin after application of Clearfil Bond bonding agent (Kuraray Co.) by the technique designed for

*Professor, Operative Dentistry. **Lecturer, Operative Dentistry. ***Instructor, Operative Dentistry. 10/l/14826

TBE JOURNAL

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DENTISTRY

I. Number of tooth forms

Table

Clearfil Tooth

forms

First premolars Second premolars First molars Second molars Third molars Total

Table

II.

Posterior

N

%

N

%

11 12 39 37 7 106

10 11 37 35 7 100

9 5 35 51 7 107

8 5 33 47 7 100

Number of types of cavity Clear61

Cavity class

I I I II Total

P-10

Posterior

Surface

N

%

Occlusal Linguokmccocclusal Buccolinguo-occlusal Mesio/distocclusal

36 36 33 1 106

34 34 31 1 100

P-10 N

%

21 19 47 44 32 30 7 7 107 100

the chemically adhesive composite resin system by Fusayama.r2 One year later a second group of 41 patients (36 men and five women) with similar caries or amalgam restorations with recurrent caries in posterior teeth were selected for restoration. They had a group total of 107 teeth, 15 of which required extensive restorations and the remaining had 32 narrow restorations (Table II). All of the teeth were in occlusion. They were restored by the same Fusayama technique using P-10 resin with Scotch Bond bonding agent (3M Co., St. Paul, Minn.). 627

SHINTANI,

Table

III.

SATOU,

AND

SATOU

Number of cavities requiring spot bases Intermediary

Product

Dycal (Caulk) Life (Kerr) HY-Bond (Shofu) Elite (GC) (No base)

base

cements Clearfil

Type

Posterior

Calcium hydroxide Calcium hydroxide Polycarboxylate cement Zinc phosphate cement

Total

P-10

79

77

16

10

4 1

7 0

6

13 107

106

Table

IV.

Evaluation criteria

Marginal adaptation (a) Little or no catch with an explorer, no visible crevices (b) Minor catch with an explorer, visible crevice (c) Major catch with an explorer (d) Fracture at margin or displacement of restoration Marginal staining (a) No marginal staining (b) Slight marginal stain in limited area (c) Stain at ah margins, deep penetration Wear (a) No anatomic change (b) Slight wear recognized by careful observation (c) Clinically remarkable wear Surface roughness (a) Comparable to the original finish (b) Roughness similar to finish with 800 mesh emery paper or more (c) Roughness similar to finish with 200 mesh emery paper or more Discoloration (a) No discoloration (b) Slight discoloration (c) Marked discoloration Recurrent caries (a) No recurrent caries (b) Visible caries, soft, chalky, or stained Postoperative sensitivity (a) No symptoms (b) Sensitivity slight or of short duration (c) Continuous sensitivity not requiring endodontics Pulp reaction upon recall (a) Normal (b) Sensitive to cold (c) Sensitive to occlusal force (d) Endodontic therapy required

All operative procedures were completed by one author (N.S.). He had graduated from the dental school 5 years before starting the test of the new material and technique

Operative Restorations 4 years after placement. Arrows indicate defects. A, @ Clearfil Posterior, no defects; B, aClearfi1 Posterior, slight crevice; C, 12 P-10, void, caries; D, /6J P-10, marginal stain, E, B P-10, no defects; F, 6 Clearfil Posterior, pink discoloration; G, n Clearfil Posterior, green discoloration; H, ri? Clearfil Posterior, caries, void, wear; I, k Clearfil Posterior, fracture; J,F Clearfil Posterior, displacement. Fig.

628

1.

technique

The amalgam restorations in teeth with recurrent caries were removed. The Caries Detector (Kuraray Co.) instru ment with

1% Acid Red. 52 solution

in propylene

glyco;

was applied to the carious cavity. Ten seconds after appli cation, the cavity was irrigated with water from a syringe The carious or undermined enamel, stained red with the detector,

was removed

by using diamond

DECEMBER

1989

or carbide

VOLUME

62

burs a

NUMBER

6

CLINICAL

STUDY

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COMPOSITE

RESINS

Fig. 2. Scanning electron micrograph of margins of restoration A in Fig. 1.

Fig. 4. Scanning electron micrograph of margins of restoration C in Fig. 1. Arrow indicates void.

Fig. 3. Scanning electron micrograph of margins of restoration B in Fig. 1. Arrow indicates slight crevice.

Fig. 5. Scanning electron micrograph of margins of restoration H in Fig. 1. Arrow indicates void and wear.

high speed. The carious dentin, also stained red, was excavated with round steel bum at low speed. The detectorstainable tissues were completely removed after repeated detection and excavation. The unstainable inner carious or normal dentin was carefully preserved. No box form of mechanical retention was created. The inclination of the marginal enamel wall was 60 to 90 degrees with no bevel. For deep cavities, a base of one of the agents listed in Table III was applied. Bases were limited to the smallest possible area in order to permit maximal etching of dentin for adhesion. Enamel and dentin walls were totally etched for 60 seconds with the etchant supplied by the manufacturer. The cavities were then spray-washed and air-dried. The bonding agent was applied to the etched enamel and dentin walls with a pellet of absorbent spongy resin and dried with a gentle application of air to evaporate the ethanol in the bonding agent. The composite resin was then inserted in

the cavities and shaped to the desired anatomy. After polymerization, the composite resin was finished with a white point under a water coolant.

THE

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Recall Four years after restoration, the patients were recalled for evaluation by clinical observation, explorer, photographs, and scanning electron microscopic (SEM) examination of replicas3 Another author (J.S.) scored the criteria listed in Table IV. The criteria for marginal adaptation, marginal staining, and recurrent caries were those established by the U. S. Public Health Service.13

RESULTS The results, based on the ratings of the restorations, are listed in Table V. Marginal ditches were almost nonexistent (Figs. 1, A and E, and 2). If present, they were shallow and short (Figs. 1, B, and 3). Slight crevices were not always

629

SHINTANI,

Table

V.

* Problems

Marginal adaptation Marginal staining Wear Surfaceroughness Discoloration Recurrent caries Postoperativepulp reaction Pulp reaction on recall

VI.

Posterior

b

P-10 c.

d

a

b

c

d

-%N%N%N%

N 73 87

64 82

28 19

26 18

1 0

1 0

-

-

88 94

82 88

15 13

14 12

2 0

2 0

-

-

96 95

91 90

6 10

6 10

3 0

3 0

-

-

98 98

92 92

7 8

7 8

2 0

2 0

-

-

65 98

61 92

39 8

37 8

2 -

2

-

-

89 103

83 96

17 4

16 4

1

-

-

102 106

96 100

3 0

3 0

1 0

107 107

100 100

0 0

0 0

-

1 0

4

4

0 0

0 0

1 -

-

0 0

0 0

2

2

0 0

0 0

Number of restorations replaced because of defects

Problems

Single

Marginal adaptation Marginal staining W&X Surface roughness Surface discoloration Recurrent caries Pulp reaction New cariesin the tooth or horizontal

bars indicate

Combined

defect

0 0 0 0 0

(3)

P-10

Posterior defects

Combined

defect

(2)

defects

(2)

0 (2)

(3)

0

(2)

(2)

0 0

3

(3)

(2)

(2)

(2)

0

0 1

0 1 combined

Single 0

(3)

defects.

stained. When present, staining occurred only on one side of the restoration (Fig. 1, D). Marginal discrepancy and staining were severe when voids or fracture.were involved (Figs. 1, C, and 4). Severe discrepancies, which indicated replacement, were present in 5 % of Clearfil Posterior resin and 4% of the P-10 resin restorations (Table VI). Wear was negligible (Fig. 1, A andE). No loss of anatomy occurred in 95 % of the restorations. Three Clearfil Posterior and two P-10 slightly worn resin restorations combined with other faults required replacement (Table VI). The finish of the restorations showed no change from the originals, which was made with a white stone. Discoloration was slight and occurred in minute voids on the surface. The discolorations were mostly brown. One anomalous Clearfil Posterior resin restoration appeared pink; another green (Fig. 1, F and G). Recurrent incipient caries occurred in 3.7 % of P-10 and 7.5% of Clearfil Posterior resin restorations. These occurred in areas of marginal discrepancy (Figs. 1, H and 5). Postoperative sensitivity to thermal change and occlusal forces, which originally occurred in only four teeth despite the deep cavities, was completely absent at the 4-year examination. All teeth remained vital. Replacement of restorations was more prevalent in complex cavities in molars (Tables VII and VIII). Replacement was generally required when marginal discrepancy accom-

630

SATOU

--%N%N%N%N

Clearfil

Vertical

AND

Evaluation results of ratings Clear61

Table

SATOU,

panied recurrent caries or wear (Table VI). Fracture or displacement occurred mainly in shallow, extensive cavities (Fig. 1, J).

DISCUSSION In contrast tc previous reports, the extensive restorations subject to occlusal forces rarely resulted in marginal fracture.3-6 When present, they were shallow and of limited extent. This may be attributed to the preparation of the enamel cavosurface margins. They were not beveled.. Reveled enamel margins, almost routinely used, are likely to result in fracture of the marginal resin.14 In addition, the beveled cavosurface angle is apt to permit a feather edge of resin, which may peel or fracture.15 Chemical adhesion impedes marginal fracture of the composite resin and limits the extent of the fault if it occurs.16Most shallow crevices found in this study did not show staining caused by retention of debris. On removal of the amalgam restorations, the recurrent caries had often penetrated deep into the dentin. Similar carious lesions were not observed after 4 years of clinical experience with the bonded composite resins. The chemical adhesion to the totally etched cavity wall seemed to inhibit the leakage and deep invasion of microorganisms into the interface of the restoration and the cavity walls. After removal of the amalgam in teeth with advanced

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1989

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CLINICAL

Table

STUDY

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COMPOSITE

RESINS

Number of replaced restorations of tooth forms

VII.

Clear51

P-10

Posterior Replacement

Tooth

Table

N

90

0 0 5 4 1 10

0 0 13 11 14 9

Restorations

11 12 39 31 7 106

First premolar Second premolar First molar Second molar Third molar Total

Replacement Restorations

N

%

9 5 35 51 7 107

0 0 3 3 1 I

0 0 9 6 14 7

Number of replaced restorations by class of cavity

VIII.

Clearfil

Posterior

P-10

Replacements Cavity

class

Tooth

surface

0cc1usaI Linguo/buccoclusal Buccolinguo-occlusal Mesio/distocclusal

I II III IV Total

Restorations

36 36 33 1 106

recurrent caries, excavation of the carious dentin resulted in extensive undermined enamel. The buccal and lingual walls sometimes consisted of enamel devoid of dentinal support. Such teeth could only be restored with a bonded composite resin, which is capable of supporting the walls of enamel. The unusual pink discoloration was probably the result of careless excavation of detector-stained dentin. The green discoloration was considered to have been caused by chemical reaction of the Life lining cement with the bonding agent. Similar discolorations were observed with this combination by other dentists. The brown stain in superficial voids was thought to be caused by debris. Careful manipulation should preclude the formation of voids.12 Larger voids were observed on fractured surfaces. Syringed composite resin may be useful to avoid such pernicious faults. It would be particularly useful to restore narrow and shallow cavities. A composite resin, fluid enough to be inserted with a syringe, should produce clinically superior results even if the physical strength is slightly lower. l7 Avoiding an unnecessary base or reducing the extent of the bases increases the area of etching, which contributes to adhesive stability and resistance to fracture. Despite the extensive occlusal restorations, wear of teeth was unexpectedly infrequent and slight in contrast to previous reports.‘, 8The improvement in wear resistance of the hybrid composite resins was meaningful. Wear contributed only in combination with other defects to the decision to replace restorations. Even if restorations are severely

THE

JOURNAL

OF PROSTHETIC

DENTISTRY

Replacements

N

%

Restorations

N

90

1 4 5 0 10

1 11 15 0 9

21 47 32 7 107

0 2 3 2 7

0 4 9 29 7

abraded, they can be repaired by the addition of bonding composite resin after reducing the surface without sacrificing dental tissue.‘* The exposed surfaces of the hybrid composites tested in this study appeared smoother than the original finish after 4 years. This was in contrast to the increased roughness reported for macrofilled composites.lg Recurrent caries occurred infrequently. It was present mostly in marginal defects such as crevices or fracture due to voids at a margin or displacement. Etching of the dentin and enamel provides maximal adhesion and bonding to the cavity ~al1s.i~~2o This may explain the low incidence and degree of recurrent caries. Postoperative sensitivity to cold or occlusion for Clearfil Posterior resin restorations was rare and slight. The sensitivity spontaneously resolved itself. It was considered the result of partial separation of the composite resin at the pulpal wal121 The initial batches of Clearfil Bond bonding agent sometimes lacked adhesive strength. This has been corrected by replacing the .Clearfil Bond bonding agent with its successor, New Bond.22 The present absences of postoperative symptoms is attributed to the adhesion to dentin after etching.21-23

CONCLUSION Two brands of the hybrid type posterior composite resins placed in extensive occlusal cavities after removal of only the caries detector-stainable tissue, etching of both enamel and dentin walls, and application of a bonding

631

SHINTANI,

agent showed no adverse pulp reaction after 4 years and may be considered suitable for posterior restorations when indicated. REFERENCES 1. Goldberg AJ, Rydinge E, Santucci EA, Racz WB. Clinical evaluation methods for posterior composite restorations. J Dent Res 1984;63:1387-, 91. 2. Leidal TI, Solem H, Rykke M. A clinical and scanning electron microscopic study of a new restorative material for use in posterior teeth. Acta Odontol Stand 198%43:1-S. 3. Lutz F, Imfeld T, Phillips RW. P-lO-Its potential as a posterior composite. Dent Mater 1985;1:61-5. JR, Lundeen TF, Sluder TB Jr, Leinfelder KF. Three-year 4. Sturdevant study of two light-cured posterior composite resins. Dent Mater 1986;2:263-8. 5. Heymann HO, Wilder AD Jr, May KN, Leinfelder KF. Two-year clinical study of composite resin in posterior teeth. Dent Mater 1986;2:3741. 6. Braem M, Lambrecbte P, Van Doren V, Vanherle G. In viuo evaluation of four posterior composites: quantitative wear measurement and clinical behavior. Dent Mater 1986,2:106-13. on a I. Phillips RW, Avery DR, Swarts ML, McCune RJ. Observations composite resin for class II restorations, three-year report. J PROSTHJXT DENT 1973;30:891-7.

8. Leinfelder KF, Sluder TB, Sockwell CL, Strickland WD, Wall JT. Clinical evaluation of composite resins as anterior and posterior restorative materials. J PROSTHET DENT 1975;33:407-16. on the occlusal wear of posterior composite resin res9. Horie KStudies torations. Part 2. Clinical evaluation. J Stomatol Sot Jpn 1984;51:45-65. 10. Fusayama T, Nakamura M, Kurosaki N, Iwaku M. Non-pressure adhesion of a new adhesive restorative resin. J Dent R.es 1979;58:1364-70. 11. Dogon IL, Stambler S. Study to determine the effectiveness of dentin bopding agents [Abstract]. J Dent Res 1981;60:627.

Availability

SATOU,

AND

SATOU

12. Fusayama T. New concepts in operative dentistry. Chicago, Berlin, Tokyo: Quintessence Publishing Co, Inc, 1980. 13. Ryge G, Snyder M. Evaluating the clinical quality of restorations. J Am Dent Assoc 1973;87:369-77. 14. Fukushima M, Setcos JC, Phillips RW. Marginal adaptation of posterior composite resin restorations [Abstract]. J Dent Res 1986;65:826. 15. Hachiya Y, Takatsu T, Hosoda H, Fusayama T. A varnish to prevent etching unrestored enamel. J PROSTHET DENT 1985;53:46-50. 16. Kubo S. Study on the mechanism of marginal fracture of the posterior composite resin. Part 1. Relation between cavity wall adhesion of the resins and marginal fracture. Jpn J Conserv Dent 1987;62:13-27. 17. Hayashihara H, Satou J, Yamane I, Kosai T, Satou N, Sbintani H, Inoue T. A study of posterior composite resin. 1. Air voids between filled composite resin and cavity wall. Jpn J Conserv Dent 1984;27:885-93. 18. Chiba K, Hosoda, H, Fusayama T. The addition of an adhesive composite resin to the same material: bond strength and clinical tecbniques. J PROSTHET DENT 1989;61:669-75. 19. Jorgensen KD, Horsted P, Janum 0, Krogh J, Schultz J. Abrasion of class I restorative resins. Stand J Dent Res 1979;87:140-5. 20. Fusayama A., Kobno A. Marginal closure of composite restorations with the gingival wall in cementum/dentin. J PROSTHET DENT 1989;61: 293-6. 21. Fusayama

T. Factors and prevention of pulp irritation by composite restoration. Quintessence Int 1987;18:633-41. 22. Nakajima A. Bond strength of adhesive composite resins. Part sive property of a new bonding agent to tooth substance and structures in the dentin. Jpn J Conserv Dent 1985;28:850-65. 23. Inokoshi S, Iwaku M, Fusayama T. Pulpal response to a new restorative resin. J Dent Res 1982;61:1014-9. Reprint

requests

adhesive 2. Adheadhesion adhesive

to:

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