Complete rehabilitation of compromised full dentitions with adhesively bonded all-ceramic single-tooth restorations: Long-term outcome in patients with and without amelogenesis imperfecta.

OBJECTIVES: This clinical follow-up evaluated the long-term outcome of full-mouth rehabilitations with adhesively bonded all-ceramic restorations in patients suffering from amelogenesis imperfecta (AI) or affected by extensive tooth wear including a loss of the vertical dimension of occlusion. MATERIALS AND METHODS: Included for evaluation were all patients treated with adhesively bonded monolithic single-tooth restorations made of silicate or lithium disilicate ceramics; allowing a maximum four missing teeth and a facial feldspathic veneering of LDS anterior crowns. After treatment, patients have been enrolled in a recall program for dental check-ups including quality assessment of the restorations. Patients answered the oral health impact profile (OHIP-14) at their last visit. RESULTS: Seventeen patients (mean age = 35 ±â€¯18 years) were observed up to 16.5 years (mean: 6.2 ±â€¯3.8 years). 12 out of 450 restorations failed due to core fracture (n = 7), tooth fracture (n = 2), one secondary caries, one chip-off grade 3, and one fixed dental prosthesis due to discomfort. The overall mean survival rate of the single-tooth restorations was estimated 99.4% at 5 and 91.4% at 10 years. The overall mean success rate was estimated 92.6% at 5 and 81.4% at 10 years, mainly due to chip-offs and crack formation (27 out of 31 relative failures). The mean annual failure rates (AFR) range between 1.5 and 2% over the years, but non-AI patients were affected more frequently by early technical complications in the facial veneering of anteriors, resulting in an AFR ranging between 5.2 and 4%. Quality assessment revealed stable color, form and marginal integrity in all patients up to ten years. The distribution of OHIP values is comparable to the representative sample of healthy patients. CONCLUSION: Adhesively bonded single-tooth restorations provided a high clinical quality in the long-run. However, while the survival and success were excellent in AI patients, restorations in non-AI patients were affected by a higher complication rate, likely related to a higher risk profile due to a history of bruxism and tooth wear.

The performance of zirconium dioxide crowns: a clinical follow-up.

Thirty-two patients who had been treated with 71 computer-aided design/computer-assisted manufacture-fabricated Cercon crowns were followed to assess clinical performance by time-to-event analysis. Clinical examinations consisted of a complete dental and oral hygiene examination and a quality assessment by modified California Dental Association criteria. Four patients (6 crowns) were lost to follow-up; another 11 crowns had to be excluded from evaluation for comparability reasons. Six of 54 evaluated crowns experienced complications (P(C) = 11.1%) throughout a mean observation time of 21 months. Survival was estimated at 0.98 over 24 months. The good overall clinical performance was affected predominantly by technical complications of the veneering ceramic (P(TC) = 9.3%).

Complex all-ceramic rehabilitation of a young patient with a severely compromised dentition: a case report.

A young patient with dentinogenesisimperfecta and a dentition severely compromised by discolorations,abrasion, and breakage of enamel on several teeth was prosthodontically treated with CAD/CAM-manufactured all-ceramic restorations. To reduce treatment risk, preparations were limited paragingivally. Maxillary anterior teeth and premolars were restored with adhesively luted ceramic crowns. All other teeth were treated with zirconia-based restorations luted with a self-etching resin-based material. Considering the deficient pretreatment situation, the use of tooth-colored restoration and luting materials yielded a satisfying functional and good esthetic result. The patient is highly satisfied, even though 3 minor chippings occurred shortly after the completion of treatment

Complete esthetic and functional rehabilitation with adhesively luted all-ceramic restorations--case report over 4.5 years.

Complete prosthodontic rehabilitation using single-tooth crowns is an invasive therapy, even though the success of single-tooth crowns is well proven. In some cases, adhesively luted glass-ceramic restorations with reduced preparation depths might be a less invasive alternative. In the case presented, a 40-year-old female patient with multiple cement restorations, erosions, dysfunctional abrasion, and gap formation in the maxillary anterior region received treatment to restore function and esthetics. Minimally invasive glass-ceramic full-coverage crowns, partial crowns, and veneers were placed using the adhesive luting technique. The functional rehabilitation included increasing the occlusal height by about 2 mm. The patient was clinically followed for 4.5 years at annual examinations, which included dental and periodontal evaluations and a clinical quality assessment applying modified California Dental Association (CDA) criteria. Observations yielded only marginal discolorations and gingival recession of minor clinical importance. No adverse events occurred; the patient was highly satisfied with the esthetic result and had no complaints.

Resonance frequency analysis and damping capacity assessment. Part I: an in vitro study on measurement reliability and a method of comparison in the determination of primary dental implant stability.

OBJECTIVES: The aims of this in vitro study were to evaluate reliability of the Osstell and Periotest devices in the assessment of implant stability and to perform a method comparison. MATERIAL AND METHODS: Commercial dental implants were inserted into bovine rib segments of different anatomical origins and densities. Repeated measurements were performed, varying (a) the torque-in force of the devices' attachment screw (the Osstell transducer and the ball attachment, insert for the Periotest device), (b) the insertion site bone quality, and (c) the thread exposure in simulated peri-implant bone defects. RESULTS: Both methods were comparably reliable and showed a strong association to each other in the classification of implant stability. As opposed to torque-forced screw attachment, the variations in bone composition, differences in inter-implant stability of adjacent implants, and peri-implant bone reduction were statistically significant for both methods. CONCLUSIONS: Both non-invasive diagnostic devices seem to be useful in the long-term follow-up of implant integration.

Resonance frequency analysis and damping capacity assessment. Part 2: peri-implant bone loss follow-up. An in vitro study with the Periotest and Osstell instruments.

OBJECTIVE: We compared the performance of damping capacity assessment (Periotest device) to resonance frequency analysis (Osstell device) in the assessment of peri-implant bone loss in an in vitro experiment. MATERIAL AND METHODS: Screw-type oral implants were polymerized into acrylic blocks. Peri-implant bone loss was simulated by successively removing defined portions of material surrounding the implants in millimeter increments. Measurement values of both devices were compared by assessing the associated measurement errors, by calculating correlation analyses and drawing scatterplots, and by means of regression analysis referring to increasing bone loss. RESULTS: Both devices produced comparable results suggesting agreement of the measured implant stability values to the actual loss of peri-implant resin. There was a noticeable correlation of the Periotest and Osstell implant stability values. CONCLUSION: The results of this experiment suggest agreement in predicting the actual implant stability with both the instruments with the Osstell instrument being the more precise device.

Hydrophilicity of elastomeric non-aqueous impression materials during setting.

OBJECTIVES: Clinically relevant accuracy of dental impressions depends on flowing and wetting properties of the applied impression materials. The major objective of this study was to develop an experimental set-up and an analysis strategy for wettability measurements of impression materials during their working time. METHODS: High-resolution drop shape analysis was used to study contact angles on thin unset films of two polyether and two vinyl polysiloxane (VPS) impression materials. Qualitative and quantitative analysis of the contact angle evolution in terms of initial values and the equilibrium state of hydrophilicity, as well as in terms of kinetics of hydrophilization were extended using a mathematical model approach. RESULTS: Compared to VPS impression materials, polyethers show pronounced and constant initial hydrophilicity throughout prescribed working time. The kinetics of the VPS impression materials towards more hydrophilic equilibrium surface states is very fast compared to polyethers. This possibly balances the disadvantage of the initial VPS impression materials hydrophobicity. Generally, the experimental and analytical methods have proven to yield detailed insights into the wetting characteristics during setting. SIGNIFICANCE: Both, high initial and a fast kinetics towards increased hydrophilicity may improve flowing and wetting processes during impression taking. Therefore, time-resolved wettability studies should be regarded when developing advanced impression materials and defining working times. They may supplement rheological studies.

Assessing the reliability of a digital preparation assistant system used in dental education.

Use of a digital preparation assistant system may improve considerably the quality of preclinical dental education, provided the system works reliably. Thus, the purpose of this pilot study was to quantitatively assess the reliability of a new preclinical digital preparation assistant system (PREPassist, KaVo, Germany). The system was used to repeatedly scan four different unprepared and four different prepared teeth both with and without repositioning. Corresponding measurements were made to quantify accuracy, repeatability, and reproducibility. This was done by estimating the measurement error. Based on this estimation, respective limits of agreement were calculated. We used these ranges, along with assessments of the measurement's accuracy, to judge whether the results satisfy our expectations for clinically acceptable measurements. For preclinical laboratory instruction, the results indicate an acceptable accuracy (mean accuracy of 89 microm) of the measurements. This assessment applies as well to repeatability, given by the range of the respective limits of agreement (range <200 microm). However, in the case of reproducibility, the limits revealed discrepancies of practical importance (range >200 microm). Reproducibility of tooth repositioning in the available mounting device is unacceptable for preclinical laboratory instruction because of the observed range >200 microm. Thus, there is a need for the manufacture of new and more reliable mounting devices because reproducibility procedures are mostly encountered in preclinical instruction in restorative techniques. In contrast to reproducibility, accuracy and repeatability are acceptable for practical purposes. Balancing advantages and disadvantages, we conclude that, in general, the PREPassist system delivers reliable results.

Thirteen-year follow-up study of resin-bonded fixed partial dentures.

OBJECTIVE: The technique of resin-bonded fixed partial dentures (RBFPD) is a well-accepted clinical technique to replace missing teeth. The survival rates reported in the literature vary widely, and the conclusions are sometimes conflicting. This study presents the clinical long-term performance of silicoated RBFPDs and also determines the main cause of failure. METHOD AND MATERIALS: Sixty-one patients with a total of 74 RBFPDs were either examined or requested to complete a questionnaire regarding their fixed partial dentures. Sixty-four were placed in the anterior region, and 10 in the posterior region. No more than one missing tooth in the posterior area and two missing teeth in the anterior region were replaced with RBFPDs. A retentive preparation was made on the abutment teeth. All the RBFPDs were adhesively seated. RESULTS: Eighteen RBFPDs failed after a mean observation time of 7.8 years (nine retention losses of one or more retainers, six carious lesions, and three veneer fractures occurred). Seven RBFPDs were rebonded, whereas the remaining 11 failures had to be replaced with conventional FPDs. Fifty-six RBFPDs were primary restorations, and seven secondary RBFPDs were used after the loss of the primary restoration. A mean survival rate better than 69% after a 13-year observation period was calculated. Including the rebonded restorations, a mean functional survival rate of 83% was estimated. A total of 18 failures (24.3%) of all restorations were observed, the main cause being loss of retention. CONCLUSION: Silicoated RBFPDs are a viable treatment means with an acceptable success expectancy.

Time needed for data collection in clinical studies on fixed prosthodontics.

PURPOSE: Realistic appraisals of time and costs are crucial for research grants and financing of clinical studies by sponsors, but little is known about the time actually needed for clinical data collection in dental studies. This survey evaluated the net time of patient contact necessary for collection and documentation of clinical data to establish an empirical base for more efficient study management and budgeting. MATERIALS AND METHODS: The time needed for the clinical examination of 41 prosthodontic patients in systematic follow-up was recorded. Examination covered dental status, oral hygiene status, and quality assessment of restorations by modified CDA criteria. Completion of the case report forms, data check, and provisions for data retrieval were also included. The recorded times were analyzed to obtain empirical estimates of the time actually needed for specific examination blocks and to detect potential variables of influence. RESULTS: Predominant time records were 5 to 10 minutes for dental status (according to status complexity) or hygiene. The time needed for CDA ranking showed a linear correlation to the number of units, approximately 1 minute each. Documentation times were similar to the total contact times of all examination blocks, between 15 and 30 minutes per patient. CONCLUSION: The overall time for collection and documentation of retrievable data is considerable (about 30 minutes, up to 1 hour). The data provide an empirical base for sound managing and budgeting of follow-up periods in clinical investigations, which is of major importance for the quality of clinical data, and thus for the success and value of clinical investigations.