Retrospective clinical investigation and survival analysis on ceramic inlays and partial ceramic crowns: results up to 7 years

This study retrospectively evaluated the clinical performance of 287 all-ceramic restorations placed during routine patient care in the University setting in the past 7 years. All patients (n = 106) with ceramic inlays or partial ceramic crowns (PCC), placed during 1988–1994 (n = 327) by five experienced dentists were asked to take part in a clinical investigation, and 92 patients with 287 restorations (232 inlays, 55 PCC) agreed to do so. The following ceramics were used: 44 (15.3%) Dicor (Dentsply), 126 (43.9%) IPS-Empress (Ivoclar), 82 (28.7%) Mirage II, 33 (11.5%) Cerec-Vita-Mark I (Vita), and 2 (0.7%) Duceram LFC (Ducera) restorations. The restorations were placed using the following luting composites: 73 (25.4%) Dual Cure Luting Cement (Optec), 81 (28.3%) Variolink high viscosity (Ivoclar), 32 (11.1%) Microfill Pontic C (Kulzer), 51 (17.8%) Dual Zement (Ivoclar), 40 (13.9%) Dicor Light Activated Cement (Dentsply), and 10 (3.5%) Vita Cerec Duo Cement (Vita). Restorations were evaluated according to the modified USPHS criteria. Kaplan-Meier analysis was used to calculate the probability of survival. Of the 287 restorations 270 (94.2%) were still in function without any need of intervention. Fourteen restorations (4.8%) had failed before starting the clinical investigation, and in three a fracture was found during the investigation. These 17 failed restorations consisted of 14 PCC and 3 ceramic inlays. The results of the clinical investigation revealed 59.2% Alpha-ratings for marginal adaptation. Only one restored tooth showed recurrent caries. The probability of survival (95% confidence interval) for 7 years was 98% (97.99–98.01%) for ceramic inlays and 56% (46–66%) for PCC. Our findings show that ceramic inlays can be regarded as an acceptable alternative to cast gold restorations within the methodological limitations of the present study. For PCC further experience with more recent ceramics is warranted. Received: 6 August 1998 / Accepted: 26 September 1998     

Three-year clinical performance of cast gold vs ceramic partial crowns

Cast gold partial crowns (CGPC) and partial ceramic crowns (PCC) are both accepted for restoring posterior teeth with extended lesions today. However, as esthetics in dentistry becomes increasingly important, CGPC are being progressively replaced by PCC. The aim of the present prospective split-mouth study was the comparison of the clinical performance of PCC and CGPC after 3 years of clinical service. Twenty-eight patients (11 men and 17 women) participated in the 3-year recall with a total of 56 restorations. In each patient, one CGPC (Degulor C) and one PCC (Vita Mark II ceramic/Cerec III) had been inserted at baseline. CGPC were placed using a zinc phosphate cement (Harvard); PCC were adhesively luted (Variolink II/Excite). All restorations were clinically assessed using modified US Public Health Service (USPHS) criteria at baseline, 1 year, 2 years, and 3 years after insertion. Twenty-eight CGPC and 14 PCC were placed in molars, and 14 PCC were placed in premolars. Early data were reported previously under the same study design. After 3 years, the evaluation according to USPHS criteria revealed no statistically significant differences between both types of restorations with the exception of marginal adaptation and marginal discoloration: A statistically significant difference within the PCC group (baseline/3 years) was determined for the criterion marginal adaptation. For the 3-year recall period, overall failure was 0% for CGPC and 6.9% for PCC. At 3 years, PCC meet American Dental Association Acceptance Guidelines criteria for tooth-colored restorative materials for posterior teeth.     

Two-year clinical performance of cast gold vs ceramic partial crowns

Cast gold partial crowns (CGPC) are an accepted means of restoring posterior teeth with extended lesions. However, for esthetic reasons, CGPC are being increasingly substituted with partial ceramic crowns (PCC). The aim of the present prospective split-mouth study was to compare the clinical performance of PCC and CGPC. There were 29 patients (male 12, female 17) who participated in the investigation for a total of 58 restorations. In each patient, one CGPC (Degulor C) and one PCC (Vita MarkII/Cerec III) were placed. CGPC were inserted using conventional zinc-phosphate cement (Harvard); PCC were adhesively luted to the cavities (Variolink II/Excite). The restorations were clinically rated using modified United States Public Health Service (USPHS) criteria at baseline and 1 and 2 years after placement. The median patient age was 38 years (range 25–54). There were 29 of the CGPC and 14 PCC placed in molars, while 15 PCC were placed in premolars. All patients were available for the 1- and the 2-year recall. One PCC (1.7%) failed and had to be replaced after 2 years in situ. The rest of the restorations were functional without need of replacement. The evaluation using USPHS criteria revealed no statistically significant differences between CGPC and PCC with the exception of anatomic form: PCC showed occlusal chipping in two cases without need of replacement. From these data, it can be concluded that PCC may provide an esthetic and tissue-conservative alternative to CGPC. However, long-term studies comparing the clinical performance and longevity of cast gold and ceramic partial crowns for posterior teeth are desirable.     

Clinical study of indirect composite resin inlays in posterior stress-bearing cavities placed by dental students: results after 4 years

Objectives

This longitudinal randomized controlled clinical trial evaluated the longevity of composite resin inlays in single- or multi-surface cavities up to 4 years.

Methods

21 dental students placed 75 Artglass and 80 Charisma composite resin inlays in class I and II cavities in posterior teeth (89 adult patients) luted with dual-curing resin cements. Clinical evaluation was performed up to 4 years using modified USPHS criteria.

Results

87.2% of Artglass and 76.6% of Charisma inlays were assessed to be clinically excellent or acceptable. Up to the 4-year recall 5 Artglass and 11 Charisma inlays failed mainly because of postoperative symptoms, bulk fracture, and loss of marginal integrity. No significant differences between both composite resin materials could be detected at 4 years for all clinical criteria (Mann-Whitney U-test, p > 0.05). The comparison of restoration performance with time yielded a significant increase in marginal discolouration and postoperative symptoms (p < 0.05), deterioration of surface texture quality, marginal and restoration integrity (p < 0.05) for both inlay systems. However, the changes were mainly effects of scoring shifts from alfa to bravo. Small inlays compared to large inlays and premolar restorations compared to molar restorations showed significant better outcome for some of the tested clinical parameters for the Artglass inlays (p < 0.05). For Charisma inlays no such influences were revealed.

Conclusions

Clinical assessment of Artglass and Charisma composite resin inlays exhibited an annual failure rate of 3.2% and 5.9% that is within the range of published data. Within the limitations of this study indirect composite inlays are a competitive restorative procedure in stress-bearing preparations.     

A 2-year clinical study of composite and ceramic inlays

Objective long-term clinical data are necessary to evaluate the performance of dental restorations. This prospective clinical trial evaluated composite and ceramic inlays for clinical acceptability as restorative materials in posterior teeth and provided 2-year results. The study involved 7 student operators placing 47 composite inlays (Tetric, blend-a-lux, Pertac) and 24 ceramic inlays (Empress) under the supervision of an experienced dentist. Clinical assessment of 56 inlays (78.9%) was performed after 2 years with modified USPHS criteria and statistically analyzed using the Mann-Whitney U test and Fisher’s exact test. All the ceramic inlays and 90% of the composite inlays were considered clinically excellent or acceptable. During the first year 3 composite inlays failed and during the second evaluation period 1 had to be replaced. Ceramic inlays produced significantly better ”anatomic form of the surface” (P=0.038) and ”integrity of the restoration” values (P=0.043). Inlays in small cavities exhibited superior ”marginal integrity” (P=0.026) and ”marginal discoloration” values (P=0.034). Fisher’s test revealed a significantly higher failure rate in molars than in bicuspids (P=0.034). Posterior tooth- colored inlays exhibited a success rate of 100% for ceramic inlays and 90% for composite inlays even if placed by relatively inexperienced but supervised student operators. Received: 4 June 2000 / Accepted: 3 August 2000     

Long-term analysis of telescopic crown retained removable partial dentures: survival and need for maintenance

OBJECTIVES: The aim of this retrospective longitudinal study was to evaluate the clinical long-term survival of telescopic crown retained removable partial dentures (TRPDs), the influencing factors on survival as well as the type and number of necessary treatments during the observation time. METHODS: The study is based on the data of 463 patients who had received a total of 554 TRPDs with a total of 1758 telescopic crowns between 1995 and 2004 in our Dental School. The influence of the patient's gender, location of the denture, number of abutment teeth per telescopic denture, their distribution (Kennedy-class) and the impact of a routinely follow-up programme on the survival probability were analysed. RESULTS: During the observation period (mean 5.3+/-2.9 years) 4.7% of the TRPDs ceased functioning and 3.8% of the abutment teeth were extracted. The survival probability after 5 years was 95.1% for the TRPDs and 95.3% for the abutment teeth. No denture with more than four abutments required replacement. Only the covariates number of abutment teeth and patient in-follow-up showed a significant (p<0.01) influence on the survival probability. 26.9% of the TRPDs needed facing repairs, 34.8% relines, 20.6% loss of cementation of a primary crown and 1% abutment tooth treatment. CONCLUSIONS: Within the limits of a retrospective study it can be concluded that the number of attachments and thorough aftercare have a considerable impact on the long-term success of TRPDs. Though loss of cementation and defects of the facings were significant in number, they did not endanger the long-term success of a TRPD at all.     

A practice‐based clinical evaluation of the survival and success of metal‐ceramic and zirconia molar crowns: 5‐year results

This practice‐based study evaluates the survival and success of conventionally luted metal‐ceramic and zirconia molar crowns fabricated by using a prolonged cooling period for the veneering porcelain. Fifty‐three patients were treated from 07/2008 to 07/2009 with either metal‐ceramic crowns (MCC) or zirconia crowns (ZC). Forty‐five patients (26 female) with 91 restorations (obser‐vational period: 64·0 ± 4·8 months) participated in a clinical follow‐up examination and were included in the study. Estimated cumulative survival (ECSv), success (ECSc) and veneering ceramic success (ECVCSc) were calculated (Kaplan–Meier) and analysed by the crown fabrication technique and the position of the restoration (Cox regression model) (P < 0·05). Five complete failures (MCC: 2, ZC: 3) were recorded (5‐year ECSv: MCC: 97·6%, (95% confidence interval (95%‐CI): [93%; 100%]/ZC: 94·0%, (95%‐CI): [87%; 100%]). Of the MCCs (n = 41), 85·0%, [95%‐CI: (77%; 96%)] remained event‐free, whereas the ECSc for the ZCs (n = 50) was 74·3% (95%‐CI): [61%; 87%]. No significant differences in ECSv (P = 0·51), ECSc (P = 0·43) and ECVCSc (P = 0·36) were detected between the two fabrication techniques. Restorations placed on terminal abutments (n = 44) demonstrated a significantly lower ECVCSc (P = 0·035), (5‐year VCF‐rate: 14·8%) than crowns placed on tooth‐neighboured abutments (n = 47), (5‐year VCF‐rate: 4·3%). In the present study, zirconia molar crowns demonstrated a 5‐year ECSv, ECSc and ECVCSc comparable to MCCs. Irrespective of the fabrication technique, crowns on terminal abutments bear a significantly increased risk for VCFs. Clinical investigations with an increased number of restorations are needed.     

Influence of the isolation method on the 10-year clinical behaviour of posterior resin composite restorations

The aims of this prospective randomised clinical study were to clinically evaluate a radiopaque, highly filled, hybrid, light-activated resin-based composite for posterior teeth (Occlusin, ICI Dental, Macclesfield, UK and GC Dental, Tokyo, Japan) and compare the performance of restorations placed using rubber dam or cotton roll isolation. One clinician placed 100 (42 Class I and 58 Class II) restorations of the material under investigation. The isolation mode for each restoration was determined randomly: 52 preparations were protected from contamination with cotton rolls and aspiration, and 48 preparations were isolated under rubber dam. At baseline and periodically thereafter (0.5, 1, 2, 3, 4, 5, 6, and 10 years), each composite was evaluated by two practitioners using a modified (USPHS) rating system. After 10 years, 37 restorations were reviewed. The results showed satisfactory clinical performance with and without rubber dam after 10 years. A concern was the number of failures at 10 years due to unsatisfactory proximal contact. The evaluations for the surviving restorations were acceptable but with a large reduction in the percentage with ideal occlusal and proximal anatomy. The 10-year comparison of isolation modes showed no statistically significant differences (Kruskal-Wallis test) for each of the evaluation criteria. Furthermore, survival analysis showed no significant difference between the groups (Mantel-Haenszel method). It was concluded that the 10-year clinical behaviour of the restorations of a posterior composite placed under well-controlled, effective isolation with cotton rolls and aspiration, was not significantly different from the behaviour of restorations placed using rubber dam isolation. Received: 7 February 2000 / Accepted: 8 March 2000     

Clinical evaluation of removable partial dentures 10 years after insertion: success rates, hygienic problems, and technical failures

The aim of this retrospective study was to examine the condition and success rate of various designs of removable partial dentures 10 years after placement. Seventy-four patients treated with 101 mainly conical crown-retained dentures (CCRDs), clasp-retained removable partial dentures (RPDs), or a combination of conical crown and clasp-retained dentures (CRPDs) were reexamined. Prosthetic findings were compared to baseline values at insertion and checked for factors that may affect them. Overall, 36.6% of the prostheses were regarded as successes, 23.8% as partial successes, and 39.6% as failures. Also, only one-third of the prostheses showed neither hygienic problems nor technical failures. The statistical analysis identified no single parameter as significantly affecting the success rate of the partial dentures. Prostheses supported by several abutment teeth had improved success, and RPDs had a higher failure rate (66.7%) than CCRDs (33.3%) and CRPDs (44.8%); however, because of the limited number of RPDs these differences were not statistically significant. Although the prostheses were unsupervised in service, the 60.4% overall success rate of the dentures was somewhat higher than in other studies on precision-retained prostheses. Received: 31 August 1999 / Accepted: 1 December 1999     

A retrospective analysis of early and delayed loading of full-arch mandibular prostheses using three different implant systems: clinical results with up to 5 years of loading

Background: Early loading of implant‐supported prostheses in the edentulous mandible is widely accepted, but do the clinical results replicate those of delayed loading? Purpose: The aim of this study was to evaluate clinical outcome and patient satisfaction with early or delayed loading in patients treated with fixed prostheses, using three different implant systems. Materials and Methods: One hundred and nine consecutively treated patients received 490 implants supporting fixed prostheses; 82 patients with Brånemark System® implants (Nobel Biocare AB, Göteborg, Sweden), 16 with Astra Tech® implants (Astra Tech AB Dental Implant system, Mölndal, Sweden), and 11 with ITI® MonoType® implants (ITI Dental Implant System®, Institute Straumann AG, Waldenburg, Switzerland). Prostheses were placed within 2 to 3 weeks in 55 patients; 54 patients underwent a two‐stage procedure. Data were collected from patient records and radiographs; 83 patients attended a clinical examination and received a questionnaire. Results: All patients had fixed prostheses at follow‐up with a mean observation time of 3.5 years. Cumulative survival rates (CSRs) were 92.5% of prostheses and 94.4% of implants for early loading, and 98.0 and 97.9% for delayed loading. The mean radiographic bone loss after the first year was small, and at 5 years less than 0.2 mm for both groups. With early loading, significantly more prostheses (p < .05) needed adjustment or replacement. Conclusion: Statistically significantly more prostheses needed adjustment or replacement in the early group. The present study suggested lower CSRs for prostheses and implants in the early loading group after 5 years; the difference was not statistically significant. Larger study samples are needed to verify statistically small differences between treatment techniques.