[Meta-analysis of anterior veneer restorations in clinical studies]. / Een systematisch literatuuroverzicht van klinisch onderzoek naar veneerfrontrestauraties.

A systematic review was used to make an inventory of clinical studies on veneer restorations. Based on a protocol articles were selected that were subsequently assessed for their quality. With 'failure of the restoration' as a study outcome, survival data of the restorations were generated from the selected studies and a mean survival result was composed. Porcelain veneer restorations showed an acceptable 3-year survival, which was favourable to the 3-year survival of preformed acrylic veneers. The quality assessment expressed that reports on clinical studies should be more standardised in order to make it easier to compare the results of different studies.

Survival of three types of veneer restorations in a clinical trial: a 2.5-year interim evaluation.

OBJECTIVES: In this clinical trial, 180 veneer restorations (VRs) were evaluated. The purpose of the study was to collect survival data and to find possible relations between survival and (1) 'type of VR', (2) 'preparation design', (3) 'operator' and (4) the patient-related variables 'tooth-type' and 'vitality of the tooth'. METHODS: The restorations were provided by seven dentists in 1 12 patients on central and lateral maxillary incisors. Experimental variables were: 'type of VR' (either direct resin composite (DC), indirect resin composite (IC) or porcelain (P)), 'preparation design' (with and without incisal overlap) and 'operator'. Failures were recorded at two levels: absolute failure (need for new restoration) and relative failure (need for repair). Survival was defined at three levels: (1) survival of original restoration (Sr, endpoints: 'absolute' failures), (2) functional survival (Sf, endpoints: 'relative' failures) and (3) overall survival (SO, endpoints: both 'absolute-' and 'relative failures'). RESULTS: The variable 'type of VR' showed significant influence on Sf and So but not on Sr. Sf and So rates of P, IC and DC were, respectively: Sf-P, 94%; So-P, 94%; Sf-IC, 94%; So-IC, 90%; Sf-DC, 80%; So-DC, 74%. VRs on vital teeth showed a significantly better survival than VRs on non-vital teeth at all survival levels. CONCLUSIONS: Preparation of the incisal edge for incisal coverage is considered to be unnecessary to assure or improve the strength of VRs. Veneers on non-vital teeth showed higher risk to fail than veneers placed on vital teeth. Porcelain veneers showed the best overall survival.

Dimensional changes during veneering procedures on discoloured teeth.

OBJECTIVES: The aim of the study was to determine the dimensional changes of teeth when veneering procedures are involved. METHODS: Fifteen discoloured central incisors were selected from a group of 180 veneer restorations (VRs) composed of three different types of materials (direct resin composite, indirect resin composite and porcelain). Impressions and dies were made before treatment, after preparation and after placement and finishing the restoration. Contact stylus profilometry and subsequent analysis of the 3-D surface images provided quantitative data of the differences between the various treatment phases. RESULTS: The preparation reduction was the most for indirect resin composite VRs and the least for direct resin composite VRs. All veneer restorations showed nearly the same thickness and dimensional change after treatment, except one, which resulted in an additional increase of volume of the tooth. CONCLUSION: From the results of this study it is concluded that the dimensions of a discoloured tooth treated with a veneer restoration unintentionally increased, resulting in overcontour.

Meta-analysis of anterior veneer restorations in clinical studies.

OBJECTIVES: To make an inventory of clinical studies on veneer restorations (VRs) using a meta-analysis review procedure and to aggregate an overall survival result for four types of VRs. METHODS: From the dental literature published from 1983 to November 1996, papers were selected using an in- and exclusion protocol in a two-step procedure. Additionally, the papers selected were subjected to a quality assessment. Although not all studies used an identical definition of 'failure of a restoration', this item was chosen to be the common study outcome. After a homogeneity test, cumulative survival curves were constructed by pooling the data from the studies. RESULTS: On a 0-1 scale, the weighted overall mean quality score of the studies was 0.57 (s.e. 0.09). There was adequate agreement between the independent assessors. The results of the quality assessment could not be used as weights for the survivals, but the quality outcome supports the description of the sample of studies. From the nine studies on porcelain VRs, the pooled cumulative proportion of survival after 3 years was 0.92 (s.e. 0.01) and from three studies on preformed acrylic VRs this figure was 0.74 (s.e. 0.03). From both direct and indirect resin composite VRs, data from only one study were available after 2.5 and 2 years, respectively. CONCLUSION: The evaluative and statistical basis of clinical VR studies may be improved to obtain an effective inference of the results. Furthermore, porcelain VRs show acceptable longevity after 3 years, which appears to be better than that of preformed acrylic VRs.

Recognition of veneer restorations by dentists and beautician students.

Three types of veneer restorations (VRs) were evaluated for recognition by two groups of observers to study the aesthetic result. The different types of VRs were: porcelain, direct resin composite and indirect resin composite. One month after insertion of the VRs, colour transparencies were made of smiling patients randomly selected from a group of 112 patients participating in a clinical trial. The slides were evaluated by five dentists who were not familiar with the patients and by 25 beautician students (BS). Dentists were asked to locate the VRs which were present in the patients and to specify the type of VR. BS were only asked to locate the VRs. To trace a possible relationship between the aesthetic result of the treatment and a number of variables, ANOVA was applied to evaluate the variables: 'discolouration of the teeth' before treatment, 'type of VR' and 'number of VRs'. Agreements in judgement were expressed in Cohen-Kappa coefficients. The results showed that the dentists could locate the VRs quite well (Kappa coefficient 0.64 +/- 0.28) but for BS this was lower (Kappa coefficient 0.43 +/- 0.27). The more VRs were made in one patient, the more difficult it was to locate them correctly. The other variables had no significant effect on the recognition of the VRs. It was not possible for the dentist observers to differentiate between the types of VRs.

patients' satisfaction with different types of veneer restorations.

OBJECTIVES: The aim of this study was to measure the satisfaction of patients with respect to the aesthetics of veneer restorations (VRs) and to identify potential factors influencing their satisfaction. MATERIALS AND METHODS: One hundred and eighty VRs of three different types (direct composite, indirect composite and porcelain) were placed on anterior teeth. Patients were asked to fill in questionnaires at baseline and at one- and two-year recalls. RESULTS: At baseline the overall satisfaction was 76%, after two years this was 78%. The variable 'type of VR' was the only factor measured that had a significant influence on the satisfaction of the patient. At the two-year evaluation patients with porcelain VRs were more satisfied than those with direct composite VRs (P < 0.05). CONCLUSIONS: From the results of this study it is concluded that differences in clinical procedures had no effect on satisfaction. Also the number of VRs had not influenced the level of satisfaction. After two years a significant difference was observed for the variable 'type of VR', with the best results for porcelain.

Treatment times for three different types of veneer restorations.

In a longitudinal clinical trial the treatment times needed for the fabrication of veneer restorations (VRs) were recorded and analysed. Treatment times were determined for: (1) direct resin composite (DC), (2) indirect resin composite (IC) and (3) porcelain (P) veneer restorations and for two preparation designs, with and without incisal coverage. Significant effects on the treatment times were found for the factors: (1) type of VR, (2) operator, (3) number of VRs and (4) 'problems' in try-in phase for indirect VRs (IC- and P-VRs). The mean total time needed to perform one DC-VR was 46 min with a 95% confidence interval (c.i.) of 40-54 min, for one IC-VR 70 min (c.i. 60-82 min) and for one P-VR 62 min (c.i. 53-71 min). In the cases where more than one VRs were placed in one patient the times per VR were respectively: DC, 38 min (c.i. 34-44 min); IC, 59 min (c.i. 52-67 min); P, 49 min (c.i. 44-55 min). The results of this study are considered to be useful in further cost-benefit analyses.