Ultraconservative Sealed Restorations: Three-year Results

The overall objective of this clinical study was to determine the feasibility of using a sealed composite restoration to arrest caries without the removal of the carious lesion and without the traditional cavity preparation. The minimal tooth preparation (a bevel in enamel) usually did not require any anesthetic injection and conserved tooth structure. These ultraconservative sealed composite restorations placed over caries (CompS/C) have been compared with ultraconservative sealed amalgam restorations (AGS) and with the traditional outline form (unsealed) amalgam restorations (AGU). This clinical study has shown that: (1) caries can be arrested by the CompS/C restoration for a period of three years; (2) the marginal integrity of the AGS restorations showed a definite trend toward improvement as compared to the AGU restorations; and (3) complete sealant retention over posterior restorations was similar in both the CompS/C and the AGS groups during the first two years; however, at Year 3 complete sealant retention was 16 percent higher in the CompS/C than in the AGS group.     

Sealed restorations: 5-year results.

This clinical study determined the feasibility of a sealed resin composite restoration to arrest dental caries using a minimal tooth preparation: a bevel in enamel only without removal of the carious lesion. These ultra-conservative sealed composite restorations placed over caries (CompS/C) were compared with ultra-conservative sealed amalgam restorations (AGS) that had no "extension for prevention". The CompS/C restorations were also compared with the traditional (unsealed) amalgam restorations (AGU) with the "extension for prevention" outline form. Caries progress, as determined by standardized radiographs, revealed that after 5 years caries remained arrested under the CompS/C restorations; the marginal integrity was similar for the CompS/C and the AGS groups, and exhibited highly significant superiority to the AGU restorations (Chi square, P less than = 0.00004). Complete sealant retention over the amalgam restorations (AGS group) was less than over the composite restorations (CompS/C), and conversely, partial sealant retention was higher for the AGS group. Sealants also appeared to protect the posterior composite restorations against wear.     

Sealed restorations: 4-year results

The overall objective of this clinical study was to determine the feasibility of using a sealed composite restoration to arrest caries. This objective was to be achieved using minimal tooth preparation for Class I lesions, without the traditional Class I cavity preparation and without the removal of the carious lesion. The minimal tooth preparation consisted of no [corrected] removal of the carious lesion, bevel in enamel only, and usually not requiring any anesthetic injection. These ultra-conservative sealed composite restorations placed over caries (CompS/C) were compared with ultra-conservative sealed amalgam restorations (AGS) and with the traditional (unsealed) amalgam restorations (AGU). This study showed that: 1) caries is arrested under the CompS/C restoration for a period of 4 years; 2) sealant retention is similar in both the CompS/C and the AGS groups; 3) the marginal integrity of the AGS restorations is markedly superior to that of the AGU restorations; and 4) sealant appears to prevent wear of posterior composite restorations.     

Clinical performance of sealed composite restorations placed over caries compared with sealed and unsealed amalgam restorations

The 2-year clinical evaluations of paired occlusal restorations are presented. Each study participant received a sealed composite restoration placed over a carious lesion and either a traditional outline-form (unsealed) amalgam or an ultraconservative sealed amalgam restoration. Caries was removed before placement of both types of amalgam restorations. No important clinical differences developed among the three groups of restorations.     

Fracture strength of Class I versus Class II restored premolars tested at the marginal ridge. I. Standard preparations

Two groups of maxillary premolars with Class I cavities were prepared with one marginal ridge thickness to a width of 1.0 mm. One group was restored with amalgam and the other group with composite resin. Two groups of Class II cavities also were prepared and restored with amalgam and composite resin. The teeth in the four treatment groups were subjected to a centric load at the marginal ridge until fracture occurred. A two-factor analysis of variance revealed a statistically significant difference between the class of preparation (Class I preparations were weaker than were Class II preparations) but differences in strength between restorative materials (composite resin versus amalgam) and the interaction effect (class of preparation x restorative materials) were not found to be statistically significant (alpha = .05). A Newman-Keuls sequential range test found no statistically significant differences in strength between groups (alpha = .05). Fracture patterns were observed under scanning electron microscope. Fractures extended into the enamel and into the material in the Class I composite resin, Class I amalgam, and Class II composite resin restorations. Fractures extended only into the material in Class II amalgam restorations.     

Sealants: where we have been; where we are going

Sealants are a critical component to the restorative dentistry armamentarium. The introduction of the acid-etch technique has made the sealing of occlusal surfaces effective. Rather than waiting for an occlusal surface to break down to the extent that an occlusal Class I amalgam restoration is indicated, extending preparations to include all caries-susceptible pits and fissures, an occlusal sealant can be placed to prevent caries. Sealants have been shown to be effective when used alone over acid-etched enamel or in conjunction with a methacylate-containing adhesive. Pit and fissure caries can be restored conservatively using resin composite or amalgam, utilizing sealant to prevent future caries. The increasing use of direct and indirect resin composites for Class I and Class II restorations includes the use of sealants over restoration margins and polished resin composite. A newly developed sealant, Clinpro, extends to all pits and fissures that are desirable to seal and is efficient and effective to place.     

Fracture resistance of Class II approximal slot restorations

STATEMENT OF PROBLEM: Determination of the fracture resistance of various restorative materials in Class II approximal slot restorations has not been studied. PURPOSE: This study evaluated the effects of retention grooves and different restorative materials in Class II approximal slot restorations. To explore the possibilities for further research, the probable effects of preparation size and loading angle were investigated in a limited manner. MATERIAL AND METHODS: Ninety sound, caries-free human maxillary premolars were divided into 9 groups. The cavities were prepared either by hand or in a computer-controlled CNC machine with or without retention grooves. Four were restored with adhesive amalgam, another 4 with composite, and a single group with Compomer resin. The gingival floor depth was 1.5 mm. The specimens were loaded at an angle of 13. 5 degrees to their longitudinal axes by using a computer-controlled material testing machine until failure occurred. For one specific preparation of adhesive amalgam, loading was applied at 0 and 30 degrees to determine the probable effects of the loading angle. For a specific composite, resin application, the effects of the change in gingival floor depth were analyzed by assigning the depth to 2.0 mm. RESULTS: Composite and Compomer resin and composite exhibited better performance than amalgam. The existence of the retention grooves proved to be effective for adhesive amalgam restorations but did not have any advantageous effect in composite and Compomer restoration. CONCLUSION: For improved fracture resistance in small approximal restorations, the use of composite was the appropriate choice. Compomer also gave satisfactory results. Use of amalgam restoration should be accompanied with retention grooves and an adhesive system to improve its performance.     

The use of amalgam in pediatric dentistry

Amalgam has been widely utilized to restore posterior teeth in pediatric dentistry, and is still taught as the material of choice for Class I and Class II restorations in many dental schools in the United States and Canada. Results of clinical trials are difficult to compare due to their heterogenicity, mainly due to differences in caries risk, operator skills, study duration, or patients' age. Thus, the different studies report failure rates of amalgams ranging from 12% to over 70%. Treatment of caries should meet the needs of each particular patient, based on his/her caries risk. In general, for small occlusal lesions, a conservative preventive resin restoration, using composite or compomer in conjunction with sealant, would be more appropriate than the classic Class I amalgam preparation. For proximal lesions, amalgam would be indicated for 2-surface Class II preparations that do not extend beyond the line angles of primary teeth. This recommendation might not be appropriate for high-risk patients or for restoring first primary molars in children 4 years of age and younger where stainless steel crowns have demonstrated better longevity. Currently, amalgam demonstrates the best clinical success for Class II restorations that extend beyond the proximal line angles of permanent molars.     

Occlusal composite restorations: 4-year results

A study was performed to determine the success of a conservative cavity preparation using the principle of sealing for prevention rather than cavity extension for prevention. A total of 332 restorations were placed in 240 teeth of 110 subjects, aged 6 to 14, with a mean age of 8 years. After 4 years, 205 restorations were examined. Caries appeared in 13 teeth and sealant wear occurred in 14 restorations. Complete sealant loss was observed in eight restorations and partial loss in 38, leaving 156 restorations with complete retention of the sealant. These preliminary results show that conservative cavity preparation with sealing for prevention is a successful technique that conserves valuable tooth structure.     

Preventive resin restorations and sealants in light of current evidence

Pit and fissure sealant should be treatment option provided to all children, particularly at the age immediately after eruption of the posterior teeth and especially, but not exclusively, the permanent teeth. Preventive resin restoration is minimally invasive procedure that should be the treatment of choice for small carious lesions in the posterior teeth. The Class I amalgam should not be placed as a first-time restorative material to treat incipient or small carious lesions under any circumstances. The amount of tooth structure removal necessary for Class I Black preparation, which requires sufficient depth of amalgam and extension for prevention, is an unacceptable treatment when minimally-invasive options are available.     

Direct placement restorative materials for use in posterior teeth: the current options

The purpose of this paper is to provide guidelines to assist in the selection of dental materials for restoring posterior teeth in adolescents. Currently, amalgam is still the best plastic restorative material for some Class I cavities, and for Class II cavities and all multi-surface restorations. Tooth-coloured materials are preferred by some patients and dentists, however these alternatives are more technique sensitive than amalgam. Composite resin is the most common direct placement alternative to dental amalgam, providing patients with relatively low cost, tooth-coloured restorations. However, composite resins have limited indication, their placement is more time-consuming than for amalgam, cost-benefit considerations are a concern, difficulty in obtaining a marginal seal persists and there are few long-term studies published in the peer reviewed scientific literature. The literature currently supports the use of composite resin for the restoration of a limited range of Class I and Class II cavities. Composite resin restorations are not recommended for MOD or other multi-surface restorations. In selected clinical situations, fissure sealants, preventive resin restorations and glass ionomer cement are also appropriate materials to use to restore posterior teeth. Fissure sealants, when properly maintained, can play a significant role in the prevention and control of dental caries in pits and fissures in primary and permanent teeth. Preventive resin restorations should be placed to restore deep pits and fissures with incipient caries and/or developmental defects in primary and permanent teeth. Glass ionomer cement may be used for restoring Class V cavities where appearance is not the primary concern, for conservative Class III cavities, and as a provisional restorative material. It is not recommended for Class II or IV restorations.     

Reasons for restorative therapy and the longevity of restorations in adults

The aim of this study was to obtain information on the restorative dental care of adults in Finland. A random sample of private dentists was drawn from the register, and in spring 2000 they were sent a questionnaire requesting them to record information for each restoration placed during one ordinary working day. A total of 800 dentists were contacted and 548 responded. The dentists reported placement of 3,455 restorations. Of these, 5% were Class I, 36% were Class II, 13% were Class III, 9% were Class IV, 21% were Class V, and 16% were extensive restorations including 4 or more surfaces. Overall, composite resin was the most common restorative material, and it was used in 79% of the restorations, whereas amalgam was used in 5%, compomers in 4%, and glass ionomers (either conventional or resin‐modified) in 7% of cases. In 5% of the cases, the tooth was restored with indirect restorative methods, using either gold or ceramic materials. Of the treatments, 65% were replacements of previous restorations. Secondary caries was the most common reason for replacement (36%, 52%, and 41% for composite, glass ionomer, and amalgam, respectively). Other common reasons were fractures of the tooth or restoration (23%, 11%, and 22% for composite, glass ionomer, and amalgam, respectively) and lost composite restorations (16%). The median age of failed restorations was 15 years for amalgam, 6 years for composite, and 7 years for conventional glass ionomer. Although the longevity of tooth coloured restorations was shorter than that of amalgam, comparisons with our previous studies indicate improved survival periods for tooth coloured materials.     

Marginal adaptation of amalgam and resin composite restorations in Class II conservative preparations.

OBJECTIVE: The purpose of this study was to compare and contrast the performance, in terms of marginal adaptation, of a non-gamma-2 amalgam alloy with a compact-filled light-cured composite in the restoration of Class II preparations of conservative design. METHOD AND MATERIALS: Fifty recently extracted teeth were selected for the study. The teeth were restored with either a non-gamma-2 amalgam alloy, Dispersalloy, or a compact-filled resin composite, Z100, using standard techniques. The marginal adaptation of the restorative materials to the proximal surface outline form of each preparation was assessed at magnification x30. RESULTS: Highly significant differences were demonstrated in the mean percentages of perfect margins in all 3 segments of the proximal boxes of the restorations with the resin composite performing significantly better than the amalgam. The percentages of marginal fissuring were significantly higher in the amalgam restorations, except at the cervical margin, where the incidence of fissuring was almost the same for the amalgam and resin composite restorations. The resin composite restorations had significantly fewer underfilled margins than the amalgam restorations. CONCLUSION: In the conservative Class II preparations, the amalgam restorations were of poor quality with respect to marginal adaptation, compared with the resin composite restorations. It is suggested that the use of amalgam as a control in a clinical evaluation of resin composite restorations in conservative preparations cannot be justified, because it is apparently not possible to compare restorations of equivalent initial quality.     

Long-term evaluation of extensive restorations in permanent teeth

OBJECTIVES: The present prospective, longitudinal study assessed the outcome of posterior extensive restorations and identified risk factors for failure of the restorations. MATERIALS AND METHODS: The sample consisted of 722 amalgam restorations, 115 composite resin restorations and 89 crowns placed in 428 adults by one dentist from 1982 to 1999 in Belgium. Well-defined criteria were used for cavity preparation design, type of retention and selection of restorative material. RESULTS: At the closure of the study 48% of the restorations were well functioning, 24% were lost to lack of follow-up, and 28% had failed. The most frequent reasons for failure were fracture of restoration (8%), secondary caries (6%) and fracture of cusp (5%). Failures were more often found in premolar teeth (34%) than in molars (27%) (P=0.05) and occurred in 28% of the amalgam restorations, 30% of the resin restorations and 24% of the crowns (P=0.55). Molar restorations were more frequently repaired than replaced in contrast to premolar restorations. The highest percentage of extractions was related to complete amalgam restorations in premolars. The Kaplan-Meier median survival times were 12.8 years for amalgam restorations, 7.8 years for resin restorations, and more than 14.6 years for crowns, considering all retreatment as failures (P=0.002). The survival was influenced by extension of restoration, age of patient, pulpal vitality, 3-year period of treatment, use of base material and dentinal retentive pins. CONCLUSION: Within the limits of the study the data support the view that extensive amalgam restorations but not composite resin restorations can be used as an appropriate alternative to crowns, with due consideration to the longevity of the restorations.     

Microleakage of extended and nonextended Class I composite resin and sealant restorations

Favorable results of composite resin sealant restorations in narrow occlusal cavities raise the question of whether extended cavity preparation is justified. Larger restorations are subject to increased polymerization shrinkage. Microleakage of extended and nonextended composite resin sealant restorations was tested in this study. Forty extracted caries-free third molars were allocated to four experimental groups. Occlusal cavity preparations were prepared, varying from narrow cavities restricted to the central fossa to preparations eradicating all fissures. Composite resin restorations were inserted with or without a base and with or without a sealant. Control restorations were inserted in nonetched preparations. Microleakage occurred when cavities were not etched and occassionally when a sealant was not applied. Conclusions indicate that a class I composite resin restoration extended beyond the central fossa can be free of microleakage if covered with a fissure sealant.     

Reasons for restorative therapy and the longevity of restorations in adults

The aim of this study was to obtain information on the restorative dental care of adults in Finland. A random sample of private dentists was drawn from the register, and in spring 2000 they were sent a questionnaire requesting them to record information for each restoration placed during one ordinary working day. A total of 800 dentists were contacted and 548 responded. The dentists reported placement of 3,455 restorations. Of these, 5% were Class I, 36% were Class II, 13% were Class III, 9% were Class IV, 21% were Class V, and 16% were extensive restorations including 4 or more surfaces. Overall, composite resin was the most common restorative material, and it was used in 79% of the restorations, whereas amalgam was used in 50%, compomers in 4%, and glass ionomers (either conventional or resin-modified) in 7% of cases. In 5%, of the cases, the tooth was restored with indirect restorative methods, using either gold or ceramic materials. Of the treatments, 65% were replacements of previous restorations. Secondary caries was the most common reason for replacement (36%, 52%, and 41% for composite, glass ionomer, and amalgam, respectively). Other common reasons were fractures of the tooth or restoration (23%, 11%, and 22% for composite, glass ionomer, and amalgam, respectively) and lost composite restorations (16%). The median age of failed restorations was 15 years for amalgam, 6 years for composite, and 7 years for conventional glass ionomer. Although the longevity of tooth coloured restorations was shorter than that of amalgam, comparisons with our previous studies indicate improved survival periods for tooth coloured materials.     

Early failure of Class II resin composite versus Class II amalgam restorations placed by dental students

Using the information from remake request slips in a dental school's predoctoral clinic, we examined the short-term survival of Class II resin composite restorations versus Class II dental amalgam restorations. In the student clinic, resin composite is used in approximately 58 percent of Class II restorations placed, and dental amalgam is used in the remaining 42 percent. In the period examined, Class II resin composite restorations were ten times more likely to be replaced at no cost to the patient than Class II dental amalgam restorations. A total of eighty-four resin composite restorations and six amalgam restorations were replaced due to an identified failure.     

Placement and replacement of restorations by selected practitioners

BACKGROUND: There are few Australian data on the reasons for placement and replacement of restorations, and the extent to which these are carried out in general practice. METHODS: A survey was carried out of approximately 100 consecutive restorations placed by each of 28 general dental practitioners. The data were coded and statistically analyzed for various associations. RESULTS: Resin composite was used twice as frequently as amalgam as a restorative material, and nearly four times as often as glass-ionomer cement. Secondary caries was the principal reason for replacing restorations, affecting predominantly amalgam restorations in Class I and Class V cavities. Teeth restored with amalgam fractured nearly twice as often as teeth restored with resin composite. The average ages of amalgam, resin composite and glass-ionomers at replacement were 13.6, 7.1 and 5.7 years respectively. CONCLUSIONS: Amalgam has the longest clinical service life, but is associated with more tooth fracture. Secondary caries is the main reason for replacing restorations. The anti-cariogenic effect of glass-ionomer cement is equivocal.     

Repair of defective Class I composite resin restorations

Composite resin restorations undergo dimensional changes that can eventually result in marginal defects. Unlike silver amalgam restorations, which usually should be completely removed before the tooth is restored again, bonded composite resin restorations can often be repaired. This report demonstrates a step-by-step technique for repairing a defective Class I composite resin restoration with a new application of resin after elimination of the defect. The method has proved successful over the last 8 years.     

Effect of retention grooves on fracture strength of Class 2 composite resin and amalgam restorations

The effect of approximal retention grooves on fracture strengths of class 2 composite resin and amalgam restorations was tested in vitro. Results indicated that retention grooves significantly improved (P less than 0.05) the compressive strength of amalgam restorations (38.6% stronger). For posterior composite resin restorations, there was no significant difference in mean compressive strength of restorations in preparations with and without retention grooves.