California Dental Association Quality Research Articles

Clinical evaluation of 3D-printed zirconia crowns fabricated by selective laser melting (SLM) for posterior teeth restorations: Short-term pilot study

Background/purposeZirconia crowns (ZrC) without veneering porcelain have become an effective alternative in clinical practice. Monolithic zirconia restorations fabricated by the dry milling method do not have acceptable clinical properties. This study evaluated the periodontal qualities of three-dimensional printed ZrC using the modified United States Public Health Service (USPHS) criteria. Materials and methodsA total of 15 patients who required dental crowns were recruited, and all 15 teeth were restored with digital 3D-printed ZrC. All crowns were assessed at the time of crown placement and 2, 6, and 24 weeks post-placement. Clinical parameters, including plaque index, gingival index, probing depth, crown marginal integrity, and attrition of the antagonist's teeth, were evaluated and recorded. ResultsAccording to the Modified California Dental Association quality evaluation system, 100% of the crowns received satisfactory grades. Despite the significant increase in plaque index and gingival index at two weeks post-ZrC placement, there was no deterioration in probing depth. Moreover, there was discard usage of ZrC on the antagonist's teeth at 24 weeks posttreatment. Of the 15 crowns, one tooth had to be extracted due to a vertical root fracture. Overall, the digital 3D-printed crowns showed no adverse effects on periodontal tissues after 24 weeks of follow-up. ConclusionThe 3D-printed ZrC showed no periodontal problems. It can serve as an alternative for patients, particularly those with high esthetic expectations.

Clinical Evaluation of Monolithic Zirconia Crowns: A Short-Term Pilot Report.

This study aimed to prospectively evaluate the clinical performance of monolithic zirconia crowns made of yttria-stabilized tetragonal zirconia polycrystal. A total of 26 crowns placed on premolar or molar teeth in 18 patients were evaluated at the time of crown placement and at 2 weeks, 6 months, 1 year, and 2 years after placement. Twenty-five crowns rated as satisfactory according to the California Dental Association quality evaluation system. Most of the abutment and antagonist teeth showed good periodontal condition. An enamel cracking occurred on one antagonist tooth 1 year after placement. Monolithic zirconia crowns can be a clinically acceptable prosthetic option.

Assessment of the Quality of Composite Resin Restorations

Purpose: To evaluate the quality of the composite restorations. Material and Methods: A total of 246 composite restorations in 125 patients attending the Conservative Dentistry Clinics at the Faculty of Dentistry, University of Khartoum were examined. Both anterior and posterior composite restorations were included. California Dental Association Quality Evaluation System was used for the evaluation. Results: Fifty two percent of all restorations were found to be satisfactory, while the remaining 48% were not satisfactory. With regard to surface and colour criteria, colour mismatch within the range (34.8%) and slight surface roughness (26.6%) were the most common defects. The most frequent defects of the anatomical form were restoration overhang (26.8%). The majority of the restorations above 4 years old were of unacceptable anatomical form (66.7%), and their marginal integrity was less acceptable than more recent restorations (46.7%). Conclusions: Forty eight percent of the examined composite restorations needed to be replaced, and the unacceptable anatomic form was the main cause of failure of composite restorations.

A prospective evaluation of zirconia posterior fixed dental prostheses: Three-year clinical results

Although the favorable mechanical properties of zirconium oxide-based ceramics have increased the acceptance of fixed dental prostheses for use in the posterior regions of the mouth in recent years, there are few clinical studies documenting the longevity of these restorations. Furthermore, certain complications must be resolved before the material is used more extensively. The purpose of this randomized prospective study was to evaluate the clinical performance of zirconia (Lava) 3-unit posterior fixed dental prostheses. Twenty 3-unit fixed dental prostheses were placed in 17 participants to replace a second premolar or a first molar. Eleven were placed in the maxilla and 9 in the mandible. All abutment teeth were prepared with a chamfer finish line of 0.8 to 1 mm, and frameworks were prepared with the Lava system. Restorations were cemented with a resin cement. Two calibrated examiners independently evaluated the fixed dental prostheses 1 week (baseline) and 1, 2, and 3 years after placement with the California Dental Association quality evaluation system. The periodontal parameters: the gingival index, plaque index, margin index, and the probing depths of abutment teeth and contralateral teeth were assessed. Data were analyzed by using descriptive statistics and the Wilcoxon signed-rank test (α=.05). All fixed dental prostheses were rated satisfactory after 3 years, and no fracture of the framework was observed during the observation period. One fixed dental prostheses was lost because of a biological complication at the 3-year examination, and a small degree of chipping of the veneering ceramic was observed in 2 participants. No significant differences among the periodontal parameters of the test and control teeth were observed except for the margin index. The results of a 3-year evaluation suggest that posterior zirconia 3-unit fixed dental prostheses are a reliable treatment.

Clinical Evaluation of 209 All‐Ceramic Single Crowns Cemented on Natural and Implant‐Supported Abutments with Different Luting Agents: A 6‐Year Retrospective Study

The Procera AllCeram™ system (Nobel Biocare AB, Göteborg, Sweden) is a valid alternative to metal-ceramic restorations. However, limited long-term data of its use for single crowns on natural and implant-supported abutments are available. The present study aimed at evaluating the clinical performances of Procera AllCeram single crowns in both anterior and posterior regions of the oral cavity either on natural tooth or implant abutments over a period of 6 years. Two hundred nine single crowns were fabricated and used in 112 patients. Zinc phosphate and resin luting agents were used to cement the restorations. The crowns were evaluated according to the California Dental Association's quality assessment system. Three crowns were lost at follow-up. Of the 206 restorations, which completed the 6-year follow-up, 9 crowns were affected by mechanical complications and 7 crowns failed. All surviving crowns were ranked as either excellent or acceptable. Cumulative survival and success rates of 95.2 and 90.9%, respectively, were recorded. Within the limitations of the present study, Procera AllCeram crowns proved to be a reliable clinical option to restore both anterior and posterior missing teeth either on natural or implant abutments. The resin cement used in the present study performed better than the zinc phosphate luting agent.

Clinical evaluation of posterior all-ceramic FPDs (Cercon): A prospective clinical pilot study

This study prospectively evaluated the clinical performance of posterior zirconium-oxide-based all-ceramic fixed partial dentures (FPDs). Forty-two abutments of 21 Cercon FPDs were fitted in 20 patients at the Tsurumi University Dental Hospital from August 2005 to August 2006. The performance of these FPDs was evaluated using the California Dental Association (CDA) quality assessment system at baseline and at all follow-up examinations. All FPDs were examined after a mean observation period of 28.1 (+/-3.4) months. During the observation period, no fracturing of FPDs was seen. All of the FPDs examined were rated as satisfactory with regard to all factors at the follow-up examinations based on the CDA quality assessment criteria. Within the limitations of this short-term clinical study, no core framework fractures were seen. According to the CDA criteria, 100% of the FPDs were rated as satisfactory during this observation period.

Clinical Evaluation of Porcelain Fused to Electroformed Gold Coping Crowns: Preliminary Results after 30-43 Months

Purpose: Porcelain-fused-to-gold copings prepared by the electroforming technique were introduced as an alternative to conventional metal/ceramic crowns. However, there are few clinical studies that have evaluated this technique. The purpose of this study was to prospectively evaluate the clinical performance of Auro Galvano Crowns (AGCs).Methods: One hundred and twenty-seven AGCs were used to treat patients at the Tsurumi University Dental Hospital from October 2002 to December 2003. All the crowns were evaluated using the modified California Dental Association (CDA) quality assessment system at baseline and at all follow-up appointments.Results: A total of 122, 119, and 72 crowns were examined at the 1-, 2-, and 3-year follow-ups, respectively. During the observation period, four crowns were removed because of partial fracture of the veneered porcelain in premolar and posterior teeth. No chips were detected during this observation period. All of the crowns examined were rated as satisfactory according to the modified CDA quality assessment system. During this period, the cumulative survival rate was 96.1%.Conclusion: Within the limitations of this clinical study, AGCs luted with adhesive resin cement functioned satisfactorily with a relatively low fracture rate compared to porcelain-fused-to-metal (PFM) and all-ceramic crowns. Since the observation period was short, long-term observation will be necessary in order to further evaluate these crowns.

Prospective Clinical Study of Procera AllCeram Crowns:2-3 year Preliminary Results

Purpose: The Procera system was introduced in Japan in December 2000, however, there have been few clinical evaluations of the Procera AllCeram crowns. The purpose of this study was to prospectively evaluate the clinical performance of Procera AllCeram crowns.Methods: One hundred and one Procera AllCeram crowns were placed in patients' oral cavities at the Tsurumi University Dental Hospital from July 2001 to October 2002. The performance of these crowns was evaluated using the California Dental Association (CDA) quality assessment system at baseline and at all followup examinations.Results: A total of 101, 97 and 67 crowns were examined at 1, 2 and 3 years after their fixation, respectively. During the three-year period, six crowns were removed because of fracture of the copings, fracture of the porcelain veneer, root fracture, or esthetic problems. Small incisal chips were detected in three crowns. All of the crowns examined were rated as satisfactory according to the CDA quality assessment criteria, except for the surface and anatomic form.Conclusion: During the 3-year follow-up period, six crowns were removed, yielding a cumulative survival rate of 93.2%. All (100%) of the Procera AllCeram crowns were rated as satisfactory in terms of the clinical performance according to the CDA criteria, and to be useful for both anterior and posterior teeth. However, the observation period was short, and evaluation over a longer period of time is necessary for a more precise evaluation of these crowns.

Retrospective Clinical Evaluation of 86 Procera AllCeram™ Anterior Single Crowns on Natural and Implant‐Supported Abutments

The Procera AllCeram (Nobel Biocare AB, Göteborg, Sweden, and Procera Sandvik AB, Stockholm, Sweden) technique is one alternative to metal-ceramic restorations. However, few long-term evaluations of its use for single crowns on natural and implant-supported abutments are available. The aim of the present study was to assess the clinical performance of Procera AllCeram single crowns when placed in aesthetic sites supported by either natural teeth or implants over a period of 48 months. Eighty-six single crowns were fabricated and used in 51 patients. The restorations were examined according to the California Dental Association's quality assessment system. One crown was lost after 20 months of follow-up. Of the 85 restorations that completed the 48-month follow-up, only one crown (1.2%) showed a veneering porcelain chip. All crowns were ranked as either excellent or acceptable. The success rates of single crowns supported by natural tooth and implant-supported abutments were 100% and 98.3%, respectively; the total crown success rate was 98.8%. Within the limitations of the present study, Procera AllCeram crowns proved to be a reliable therapeutic choice for the restoration of anterior teeth on both natural and implant-supported abutments. The hybrid glass-ionomer cement used in the present study appeared to be a reliable luting agent.

Precision of fit and clinical evaluation of all‐ceramic full restorations followed between 0·5 and 5 years

Currently CAD-CAM systems are rapidly gaining importance in dental practice as some of their products aim to combine aesthetics with strength and are free of metals. This study reports on the crown adaptation, marginal fit and clinical behaviour of 300 all-ceramic full coverage restorations (Procera, Gothenburg, Sweden) placed in one clinical centre and followed up to 5 years. The marginal fit and coping adaptation before and after luting was determined by direct measurement as well as after sectioning in a laboratory study. Three hundred all-ceram restorations were installed in 165 patients between 1994 and 1998. Before the end of 2000, patients were recalled to assess their restorations, using the California Dental Association quality evaluation index, their own appreciation, as well as the reaction towards the periodontium. The in vitro data revealed a mean marginal adaptation of 30 microm, before and after luting of the Al(2)0(3)-coping onto the tooth. However, at the deepest part of the chamfer, the distance increased to 135 microm. In the clinical study only one restoration fractured, while in 6% small porcelain infractions occurred. After polishing the latter, no persistent patient complaints remained. At the last recall visit 1.8% of the margins were rated unacceptable. Dentists rated 72 and 78% of the restorations excellent for surface, colour and anatomic form respectively. Eighty-seven per cent of the patients rated their restorations more than 7/10 on an ordered analogue scale for aesthetics as well as for function.

Quality of fixed prosthodontics after twenty-two years

After an observation period of 22 years, this study was conducted to clinically examine and interview patients who in 1984 and 1989 had participated in similar investigations regarding the quality, over time, of treatments with fixed partial dentures. The patients were examined by two standardized and experienced clinicians using the California Dental Association quality rating system, their results indicating that after 22 years the overall survival rates were 46.5% and 41.1% for the originally placed crowns and pontics, respectively. However, a continuing decrease of the crown quality rating was noted during the more than 20-year-long observation period. Restorative treatments with common types of fixed partial dentures can therefore be regarded as both safe and reliable over long periods of time.

Quality of fixed prosthodontics after 15 years.

Interviews and/or clinical examinations by means of the California Dental Association quality evaluation system were carried out in a group of persons who had received extensive restorative treatments with fixed partial dentures 15 years before this study. The studied group consisted of 77 persons who agreed to participate from an original group of 150 persons selected at random from the Swedish Dental Insurance System records. Of the original group 20 had died, 17 were not traceable or not able to participate for medical reasons, and 36 declined to participate. Thirty-two per cent of the recorded reconstructions had been lost, and 8% partially lost during the 15-year period. Thirty-five per cent of the reconstructions were rated as Satisfactory, whereas the remaining ones had mixed clinical quality ratings. Failures and Not Acceptable quality ratings were found to be caused mainly by fractures, loss of retention, and/or dental caries.

A 3-year clinical study of alternatives to high noble dental casting alloys type 3

For the purpose of evaluating the quality of dental casting alloys, 22 patients were recalled for clinical examination 3 years after insertion of crowns and bridges made from the low-gold alloy Midas and the silver-palladium alloy Albacast. A high-gold alloy, JS C, served as a reference alloy. The examination included registrations of tarnish, plaque index, gingival index, and margin index. In addition, the California Dental Association's quality evaluation of dental care was used by two independent calibrated examiners. From the results of the present study it can be concluded that the crowns made from the alloy Midas in the annealed condition and the alloy Albacast are well suited for clinical use. Some tarnish appeared, but this may occur intermittently.