Longevity of extensive class II open-sandwich restorations with a resin-modified glass-ionomer cement.

Several new techniques have been introduced for use in the esthetic restoration of posterior cavities to substitute for the presumed toxicity of amalgam. Composite-laminated glass-ionomer cement restorations, the sandwich technique, have been recommended for caries-risk patients. Clinical evaluation of the use of conventional glass-ionomer cements in the open-sandwich restoration has shown a high failure rate. The aim of this study was to evaluate the durability and cariostatic effect of a modified open-sandwich restoration utilizing a resin-modified glass-ionomer cement (RMGIC) in large cavities. The materials consisted of 274 mostly extensive Class II Vitremer/Z100 restorations performed by four dentists in 168 adults. Six experimental groups were investigated. In four groups a thick and in two groups a thin layer of cement was placed. Cavity conditioning before application of the RMGIC self-etching primer was done in 3 groups with polyacrylic acid and in one group with maleic acid; in two groups, only water rinsing was performed. The restorations were evaluated at baseline and after 6, 12, 24, and 36 months according to modified USPHS criteria (van Dijken, 1986). After 3 years, 239 restorations were evaluated. Twelve (5%) were estimated as non-acceptable. Two were replaced, and seven were repaired with resin composite. Tooth fractures were observed in 2.5%. Slight erosion of the RMGIC part was seen in 4%, and in one case operative treatment was indicated. Post-operative sensitivity was reported for 9 teeth. Forty-three percent of the patients were considered as caries-risk patients. Only one restoration showed secondary caries. The three-year results indicated that the modified open-sandwich restoration is an appropriate alternative to amalgam including extensive restorations.     

Two-year evaluation of Class II resin-modified glass ionomer cement/composite open sandwich and composite restorations

Restorations made of a combination of resin modified glass ionomer cement (RMGIC) and composite resin (CR) – open sandwich fillings – have been recommended for use in proximal boxes of molar cavities. The aim of this study was to compare the clinical behaviour over time of RMGIC/CR sandwich restorations versus CR restorations in Class II molar cavities. During a period of 2 years, a total of 220 restorations were placed in 118 patients by one operator (VV). A random block allocation was used to allocate cavities to one of the two restorative techniques. Bitewing radiographs and photographs were taken at baseline and at annual recall appointments. At present, a total of 210 restorations have been evaluated after 1 year and 141 restorations after 2 years. All restorations were evaluated using a modification of USPHS criteria. A total of three RMGIC/CR and two CR restorations (2.8%) were rated as failures caused by endodontic complications or major fractures. Twenty-eight teeth were reported to have postoperative sensitivity at the baseline evaluation 1 week following placement. Nine RMGIC/CR (8.5%) and four CR (4.9%) restorations with minor fractures were rated Charlie but were still acceptable. Bitewing radiographs revealed progression of carious lesions in proximal surfaces of originally intact or restored teeth adjacent to five (5.9%) RMGIC/CR restorations and eight (10.9%) CR restorations. No statistically significant differences between the two types of restoration were observed with respect to marginal adaptation, discoloration and caries progression. However, a higher number of large CR fillings exhibited postoperative sensitivity at baseline compared to moderate CR or extensive and moderate RMGIC/CR restorations. Received: 28. January 2000 / Accepted: 8 May 2000     

Durability of resin composite restorations in high C-factor cavities: A 12-year follow-up

Objective

Polymerization shrinkage and shrinkage stress has been considered as one of the main disadvantages of resin composite restorations. Cavities with high C-factors increase the risk for interfacial failures. Several restorative techniques have been suggested to decrease the shrinkage stress. The purpose of this study was to evaluate the durability of techniques as oblique layering, indirect curing and/or a laminate with a poly-acid modified resin composite in direct Class I resin composite restorations in a 12-year follow-up.

Methods

Each of 29 patients received one or two pair(s) rather extensive Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite sandwich restoration and the second a direct resin composite restoration. Both restorations, except for the laminate layer, were placed with oblique layering and two-step curing technique. 90 restorations were evaluated annually with slightly modified USPHS criteria during 12 years.

Results

At 12 years, 38 pairs were evaluated. Two cases of slight post-operative sensitivity were observed in one patient. A cumulative failure rate of 2.4% was observed for both the resin composite and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one resin composite restoration showed a chip fracture. Five restorations were replaced due to primary proximal caries.

Conclusions

The high failure rate expected in the high C-factor Class I cavity, associated with polymerization shrinkage and shrinkage stress, were not observed. The techniques used resulted in an excellent durability for the Class I resin composite restorations.     

Two-year clinical evaluation of resinous restorative systems in non-carious cervical lesions

This controlled clinical trial evaluated the 2-year clinical performance of a one-bottle etch-and-rinse adhesive and resin composite system (Excite/Tetric Ceram) compared to a resin-modified glass ionomer cement (RMGIC) (Vitremer/3M) in non-carious cervical lesions. Seventy cervical restorations (35 resin composite - RC- restorations and 35 RMGIC restorations) were placed by a single operator in 30 patients under rubber dam isolation without mechanical preparation. All restorations were evaluated blindly by 2 independent examiners using the modified USPHS criteria at baseline, and after 6, 12 and 24 months. Data were analyzed statistically by Fisher's exact and McNemar tests. After 2 years, 59 out of 70 restorations were evaluated. As much as 78.8% retention rate was recorded for RC restorations, while 100% retention was obtained for RMGIC restorations. Fisher's exact test showed significant differences (p=0.011) for retention. However, there were no significant differences for marginal integrity, marginal discoloration, anatomic form and secondary caries between the RC and RMGIC restorations. The McNemar test detected significant differences for Excite/TC between baseline and the 2-year recall for retention (p=0.02), marginal integrity (p=0.002) and anatomic form (p=0.04). Therefore, the one-bottle etch-and-rinse bonding system/resin composite showed an inferior clinical performance compared to the RMGIC.     

Three-year performance of a calcium-, fluoride-, and hydroxyl-ions-releasing resin composite

Secondary caries is the main reason for replacement of restorations in cross-sectional studies. To prevent demineralization, the use of ion-releasing materials has been suggested. The purpose of this study was to evaluate the durability of a new resin composite that releases calcium-, fluoride- and hydroxyl ions at low pH. Sixty-nine posterior restorations were placed in 36 patients and were evaluated at baseline, 6 months, 1, 2, and 3 years with slightly modified USPHS criteria. Postoperative sensitivity was observed in 2 teeth directly after placement and in another 8 teeth after 6-12 months. Absence of the use of an adhesive bonding technique explained the symptoms. A total of 26% failures was observed during the follow-up: 13 cusp fractures, 2 partial fractures of the resin composite, 1 secondary caries and 1 endodontic treatment due to prolonged sensitivity. The cusp fractures occurred during the second part of the follow-up and may be explained by expansion of the composite material due to water expansion and/or hydrolytic degradation of the alkaline glass filler. It can be concluded that the new ion-releasing resin composite showed, despite promising pH stabilizing properties, a clinically unacceptable failure rate.     

Three-year performance of a calcium-, fluoride-, and hydroxyl-ions-releasing resin composite

Secondary caries is the main reason for replacement of restorations in cross-sectional studies. To prevent demineralization, the use of ion-releasing materials has been suggested. The purpose of this study was to evaluate the durability of a new resin composite that releases calcium-, fluoride- and hydroxyl ions at low pH. Sixty-nine posterior restorations were placed in 36 patients and were evaluated at baseline, 6 months, 1, 2, and 3 years with slightly modified USPHS criteria. Postoperative sensitivity was observed in 2 teeth directly after placement and in another 8 teeth after 6-12 months. Absence of the use of an adhesive bonding technique explained the symptoms. A total of 26% failures was observed during the follow-up: 13 cusp fractures, 2 partial fractures of the resin composite, 1 secondary caries and 1 endodontic treatment due to prolonged sensitivity. The cusp fractures occurred during the second part of the follow-up and may be explained by expansion of the composite material due to water expansion and/or hydrolytic degradation of the alkaline glass filler. It can be concluded that the new ion-releasing resin composite showed, despite promising pH stabilizing properties, a clinically unacceptable failure rate.     

Nine-year evaluation of a polyacid-modified resin composite/resin composite open sandwich technique in Class II cavities

OBJECTIVES: The aim of this study was to evaluate in an intraindividual comparison the durability of a polyacid-modified resin composite/resin composite open sandwich restoration in a 9 years follow-up. A polyacid-modified resin composite (PMRC; compomer, Dyract) was placed as an intermediate layer and covered with resin composite (RC, Prisma TPH). A direct RC restoration was used as control. METHODS: Each of 57 patients, received at least one pair of Class II restorations, one open sandwich and one resin composite control. In total 75 pairs of Class II restorations, 68 premolars and 82 molars, all in occlusion, were placed by two dentists. Most of the cavities were surrounded by enamel. The restorations were evaluated at baseline, 6, 12, 24, 36 months and 9 years by slightly modified USPHS criteria. Survival of restorations grouped on the two different techniques was determined using Kaplan-Meier survival curves. RESULTS: After 9 years, 14 of 135 evaluated restorations were estimated as unacceptable, 6 in the sandwich group and 8 in the control group. Over all annual failure rate during the 9-year period was 1.1%. The survival rate was not significant different between the two techniques (p=0.604). Reasons of failure were: secondary caries (8), fracture of tooth (1), fracture of restoration (2), endodontic treatment (3). CONCLUSIONS: Both restorative techniques showed good durability during the 9-year period. No clinical advantage was observed for the sandwich technique.     

Replacement reasons and service time of class-II amalgam restorations in relation to cavity design

Four hundred and sixty-eight class-II amalgam restorations were placed in 210 patients. The restorations had been inserted by seven Scandinavian dentists in their clinics, among their regularly attending patients. Impressions of the teeth with cavity preparations had been made, and epoxy casts fabricated. The designs and qualities of the cavities were assessed in accordance with an evaluation system for class-II cavities designed for use on models. The restorations were observed yearly and scored in accordance with the USPHS criteria. In case of replacement the reason was recorded, and the service time calculated. The restorations were observed throughout a period varying from 8 to 10 years. At the end of the observation period, 212 restorations had been lost owing to dropout patients, 68 restorations had been replaced, and 188 restorations remained functional. The commonest criteria for replacement were secondary caries (n = 30) and restoration bulk fractures (n = 24). Using univariate statistics and multivariate discriminant analyses, the time of service and the reasons for replacement were correlated with different clinical variables, including different indices for the dimensions and qualities of the cavity preparation. Several features of the cavity design could be associated with the service time of the restoration or with the reason for replacement, or both. Secondary caries was primarily associated with cavity design features gingivally on the proximal surface (p less than 0.001). At the patient level the rate of secondary caries correlated with the total number of restorations placed during the observation period, irrespective of the quality of the cavosurface margins or the size of the cavity. Restoration bulk fractures could be related to cavities with narrow and deep occlusal parts, or deep proximal parts (p less than 0.001). The discriminant functions predicted correctly between 70% and 93% of the actually failed restorations in the failure groups. The good prediction performance indicates that a linear discriminant analysis that includes aspects of the prepared cavity may be applied to predict the reasons for failure of restorations.     

Clinical evaluation of glass-ionomer tunnel restorations in primary molars: 36 months results

BACKGROUND: The purpose of this study was to clinically examine the efficacy of tunnel preparations in primary molars restored with glass-ionomer cement during a 36-month observation period. METHODS: A total of 233 tunnel restorations were placed in primary molars of 203 patients aged 6-10 years. Restorations were evaluated after 12, 24 and 36 months using the modified USPHS criteria for secondary caries, marginal discolouration, marginal adaptation and anatomic form. The Alpha+Bravo score (except for caries) and absence of clinical signs of endodontic complications was considered as a clinical success. RESULTS: At the end of the 36-month experimental period, the cumulative survival rate of tunnel restorations in primary molars was 72 per cent. The main reasons for failure were endodontic complications (46 per cent of the failures), secondary caries (31 per cent of the failures) and marginal ridge fractures (19 per cent of the failures). CONCLUSIONS: The tunnel preparation filled with reinforced restorative glass-ionomer cement is a suitable treatment for minimal proximal caries lesions in primary molars.     

A 6-year clinical evaluation of Class I poly-acid modified resin composite/resin composite laminate restorations cured with a two-step curing technique.

OBJECTIVE: Polymerization shrinkage is still one of the main disadvantages of resin composite restorations (RC). Especially in cavities with a high C-factor, debonding can occur. A laminate restoration including a base with a more elastic behavior might result in a better adaptation. The purpose of this study was to evaluate the durability of a combination of two techniques suggested to counter the stress formation in direct RC restorations in cavities with the highest C-factor. METHODS: Each of the 29 patients received one or two pair(s) of Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite (PMRC/RC) sandwich restoration and the second a direct RC restoration. Both restorations, except for the PMRC layer, were placed with oblique layering and two-step curing technique. Ninety restorations, 23 premolar and 67 molars, were evaluated annually with slightly modified USPHS criteria during 6 years. RESULTS: At 6 years, 41 pairs were evaluated. A cumulative failure rate of 2.4% was observed for both the RC and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one RC restoration showed non-acceptable marginal adaptation. Two cases of slight postoperative sensitivity were observed in one patient. Three restorations were partially replaced due to primary proximal caries. SIGNIFICANCE: A high durability for and no differences, were observed between both restorative techniques in Class I cavities.     

Three-year clinical performance of composite restorations placed by undergraduate dental students

This retrospective study evaluated the clinical performance and the reasons for failure of anterior and posterior composite restorations placed by undergraduate dental students over a 3-year period. All cavities were restored using Prime & Bond 2.1 and TPH (Dentsply), according to the manufacturer's indications. One hundred and two patients who had received composite restorations by third and forth year undergraduate students were recalled and examined to analyze the quality of the restorations. The restorations were evaluated using the modified USPHS system. Two hundred and fifty-six composite restorations, 170 in anterior teeth and 86 in posterior teeth, were evaluated. Eighty-five percent of the restorations were considered satisfactory after 3 years. Class II and class IV restorations presented the highest prevalence of failure. Loss of the restoration and deficient marginal adaptation were the main causes of failure. No restoration failed due to secondary caries. Most restorations placed by dental students were considered satisfactory after long-term evaluation. Failure was more prevalent in larger restorations and was not associated with secondary caries.     

Analyses of long-term clinical behavior of class-II amalgam restorations

The purpose of the study was to estimate the influence of different clinical variables on the replacement rate of class-II amalgam restorations in permanent teeth. The study included 210 patients who had 468 restorations placed by 7 Scandinavian dentists. The observation periods varied between 7 and 10 years. At the time of the last recording 188 restorations remained intact in 88 patients, whereas 68 restorations in 53 patients had been replaced. Eighty-six patients with 212 restorations had dropped out of the study. The most prevalent criteria for replacement were secondary caries (n = 30) and restoration bulk fractures (n = 24). Chi-square analyses of the relationship between the prevalence of replacements and the clinical variables indicated effects of the operator and the patients' age and caries activity (p less than 0.001). Similar results were observed when the functional time of the restorations was related to the clinical variables and analyzed by ANOVA and MCA analyses and by survival analyses using logrank and Wilcoxon tests (p less than 0.001). The survival analyses using the Lee-Desu statistic D showed in addition a slight difference between the restorations in the lower premolars and upper and lower molars. There were no differences in the clinical performance between four non-gamma-2 alloys and one conventional alloy. Furthermore, no differences were noted between the survival rates of MC, DO, and MOD restorations. In a Cox regression model the strongest effects on the estimated survival rates were associated with the patients' age and caries activity covariates (global chi-square = 23.5, df = 2, p less than 0.001), whereas the effects of the operator and the other clinical variables were insignificant.     

Survival rate of sealed, refurbished and repaired defective restorations: 4-year follow-up

The most common treatment in general dental practice is the replacement of restorations affected by secondary caries or marginal deficiencies. Alternative treatments to replacement of defective restorations, such as marginal sealing, refurbishment and repair, have demonstrated improvement of their clinical properties with minimal intervention. The aim of this clinical study was to estimate the median survival time (MST) of marginal sealing, repair and refurbishment of amalgam and resin-based composite restorations with localized defects as a treatment to increase the restoration longevity. A cohort of 66 patients, with 271 class I and II restorations clinically diagnosed with localized defects was longitudinally assessed. Each restoration was assigned to one of the following 5 groups: Marginal Sealing (n=48), Refurbishment (n=73), Repair (n=27), Replacement (n=42), and Untreated (n=81). Two calibrated examiners assessed the restorations at baseline and annually during 4 years, using the modified Ryge criteria: marginal adaptation, anatomic form, roughness, secondary caries and luster. Fifty-two patients with 208 restorations were assessed after 4 years; the distribution of restorations in the groups was as follows: Marginal Sealing (n=36), Refurbishment (n=63), Repair (n=21), Replacement (n=28) and Untreated (n=60). Kaplan Meier test indicated that the Sealed margins group showed the lowest MST while the Repair group showed the highest MST for restorations examined after 4 years of follow up. Defective amalgam and resin-based composite restorations treated by sealing of marginal gaps, refurbishment of anatomic form, luster or roughness, and repair of secondary caries lesions, had their longevity increased.     

Resin-modified and conventional glass ionomer restorations in primary teeth: 8-year results

OBJECTIVES: To compare the longevity and cariostatic effects of resin-modified (RMGIC) and conventional glass ionomer (GIC) restorations in primary teeth in the Danish Public Dental Health Service. METHODS: The sample consisted of 543 RMGIC and 451 GIC restorations in all cavity types in the primary teeth of 640 children, aged 3.0-17.5 years. The restorations were in contact with 480 unrestored surfaces. The restorations and the adjacent surfaces were followed until exfoliation/extraction of the teeth, repair/replacement of restorations or operative treatment of adjacent surfaces. Survival analyses supplied with multivariate analyses were performed to assess the influence of different factors on the longevity of restorations, occurrence of prevalent failures, and caries treatment of adjacent surfaces. RESULTS: After 8 years, 2% of the restorations were still in function and 37% of the RMGIC and 44% of the GIC restorations had been repaired or replaced. Fracture and loss of retention predominated as the reasons for failure of restorations in both materials. The 50% survival time for restorations was 55 months for RMGIC and 48 months for GIC (p = 0.01). Progression of caries lesions required operative treatment on 20% of the surfaces in contact with RMGIC and on 14% of surfaces adjacent to GIC restorations. The 75% survival time was 35 months for surfaces in contact with both materials (p = 0.37). CONCLUSIONS: RMGIC and GIC showed similar cariostatic effects on restored teeth and adjacent tooth surfaces, but RMGIC should be preferred for class II restorations in the primary dentition, and class III/V restorations should be made in GIC due to enhanced longevity.     

A five-year clinical evaluation of Class II composite resin restorations

OBJECTIVES: To study the clinical efficacy of posterior composite resin restorations placed in general practice after five years. METHODS: Two commercial composite resin systems were used. Three general practitioners placed the restorations at a Public Dental Health Service Office. The patients were not selected specifically for this study. Class II cavities were restored with Superlux Molar and P-50 APC composite systems on an alternate basis. At baseline, 63 restorations were placed in molars and premolars in 45 patients. For primary caries, generally a conservative cavity design was used (n = 23), while replacements of amalgams resulted in the larger conventional Class II design (n = 40). The restorations were assessed using a modified USPHS criteria. Wear measurements were determined by the Leinfelder method. Photographs and bite-wing radiographs were taken to supplement the clinical evaluation of colour match, marginal adaptation and recurrent caries. Saliva sampling was performed to determine the rate of secretion and the level of mutans streptococci and lactobacilli. RESULTS: At the five-year review 51 restorations were available for examination, of which nine restorations were rated clinically unacceptable. Including the failed restorations (n = 7), at the three-year review, a total of 16 restorations had failed (27.6%) over a five-year period. The most common reasons for failure were recurrent caries (n = 7) and marginal defects (n = 4). The mean wear of Superlux Molar was 167 microns and of P-50 APC 158 microns. Eight of the 11 patients with failed restorations due to caries and marginal defects had high counts of mutans streptococci at baseline. CONCLUSIONS: The failures in the present group of patients did not specifically relate to material, tooth type or cavity design. However, it is suggested that patient factors such as caries activity should be monitored and managed.     

Direct resin composite inlays/onlays: an 11 year follow-up

OBJECTIVES: The aim of this study was to present an 11-year assessment of direct resin composite inlays/onlays. METHODS: One-hundred Class II direct resin composite inlays and 34 direct resin composite restorations were placed in 40 patients. The restorations were evaluated clinically, according to modified USPHS criteria, annually over a 11-year period. RESULTS: Of the 96 inlays/onlays and 33 direct restorations evaluated at 11 years, 17. 7% in the inlay/onlay group and 27.3% in the direct restorations group were assessed as unacceptable. The differences in longevity were not statistically significant. The main reasons for failure for the inlays/onlays and direct restorations were fracture (8.3 and 12. 1%, respectively), occlusal wear in contact areas (4.2 and 6.1%, respectively) and secondary caries (4.2 and 9.1%, respectively). Eight of the non-acceptable inlays/onlays and five of the direct restorations were replaced, while the other ones were repaired with resin composite. Unacceptable wear was observed in occlusal contact areas of six restorations, in patients who were severe bruxers. For the other restorations occlusal wear was not found to be a clinical problem and no difference was observed between the inlays/onlays and direct composite restorations. The marginal adaptation of the inlays/onlays was still good at the end of the study. Ditching was only observed in a few inlays. A higher failure rate was observed in molar teeth than in premolar teeth. CONCLUSIONS: Good durability was observed for the direct resin composite inlay/onlay technique. Excellent marginal adaptation and low frequency of secondary caries in patients with high caries risk were shown. No apparent improvement of mechanical properties was obtained by the secondary heat treatment of the inlays. Also, the difference in failure rate between the resin composite direct technique and the inlay technique was not large, indicating that the more time-consuming and expensive inlay technique may not be justified. The direct inlay/onlay technique is recommended to be used in Class II cavities of high caries risk patients with cervical marginal placed in dentin.     

Radiation-induced root surface caries restored with glass-ionomer cement placed in conventional and ART cavity preparations: results at two years

BACKGROUND: There are no published studies comparing the clinical performances of more-viscous glass-ionomer cement (GIC) restorations when placed using conventional and atraumatic restorative treatment (ART) cavity preparation methods to restore root surface caries. METHODS: One dentist used encapsulated Fuji IX GP and Ketac-Molar to restore 72 conventional and 74 ART cavity preparations for 15 patients who had received cervicofacial radiation therapy. Two assessors evaluated the restorations at six, 12, and 24 months for retention, marginal defects and surface wear, and recurrent caries. RESULTS: After two years, the cumulative restoration successes were 65.2 per cent for the conventional and 66.2 per cent for the ART cavity preparations, without statistical or clinical significance (P > 0.50). Restoration dislodgement accounted for 82.8 per cent and marginal defects for 17.2 per cent of all failures. There were no instances of unsatisfactory restoration wear or recurrent caries observed. Teeth with three or more restored cervical surfaces accounted for 79.3 per cent of all failures (P < 0.0001). CONCLUSIONS: For root surface caries restored with GIC, the use of hand instruments only with the ART method was an equally effective alternative to conventional rotary instrumentation for cavity preparation. Larger restorations had higher failures, usually from dislodgement.     

A randomized controlled evaluation of posterior resin restorations of an altered resin modified glass-ionomer cement with claimed bioactivity

Objective

The objective of this randomized controlled prospective clinical trial was to evaluate the short time clinical behaviour of an altered resin modified glass-ionomer cement (RMGIC), which is claimed to possess bioactivity, in posterior restorations and to compare it intraindividually with a nanofilled resin composite.

Five year evaluation of class III composite resin restorations in cavities pre-treated with an oxalic- or a phosphoric acid conditioner

An oxalic acid solution has been proposed as a conditioning agent for resin composite restorations in two commercial adhesive systems. The durability of 163 class III restorations, including 12 class IV restorations, in cavities pre-treated with an oxalic acid total etch technique or an enamel etch with phosphoric acid was studied. Each of 52 patients received at least one of each of three experimental restorations. The restorations were evaluated yearly with slightly modified United States Public Health Service (USPHS) criteria. After 5 years 95% of the restorations were evaluated as acceptable. Reasons for failure were the fracture of four fillings, including three class IV, secondary caries contiguous to two fillings and a non-acceptable colour match for one restoration. For eight class III restorations a fracture of the incisal tooth structure was registered. No differences were seen between the three experimental restorations.     

Computer-aided direct ceramic restorations: a 10-year prospective clinical study of Cerec CAD/CAM inlays and onlays

PURPOSE: The objective of this follow-up study was to examine the performance of Cerec inlays and onlays in terms of clinical quality over a functional period of 10 years. MATERIALS AND METHODS: Of 200 Cerec inlays and onlays placed in a private practice between 1989 and early 1991, 187 restorations were observed over a period of 10 years. The restorations were fabricated chairside using the Cerec-1 computer-aided design/manufacturing (CAD/CAM) method and Vita MK I feldspathic ceramic. An adhesive technique and luting composite resin were used for seating the restorations. After 10 years, the clinical performance of the restorations was evaluated using modified USPHS criteria. The results were used to classify success and failure. RESULTS: According to Kaplan-Meier analysis, the success rate of Cerec inlays and onlays dropped to 90.4% after 10 years. A total of 15 (8%) failures were found in 11 patients. Of these failures, 73% were caused by either ceramic fractures (53%) or tooth fractures (20%). The reasons for the remaining failures were caries (20%) and endodontic problems (7%). The three-surface Cerec reconstructions were found to have the most failures. CONCLUSION: The failure rate of 8% and the drop of the survival probability rate to 90.4% after 10 years of clinical service of Cerec-1 CAD/CAM restorations made of Vita MK I feldspathic ceramic appear to be acceptable in private practice. This is particularly true in light of the very high patient satisfaction.