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At least 19 recordsLinked to original sources
PubMedDate not supplied

Failure rates of restorative procedures following dental rehabilitation under general anesthesia.

PURPOSE: The failure rates of restorative procedures for children undergoing dental rehabilitation under general anesthesia, performed by pediatric dental residents in advanced educational programs, were evaluated in order to determine treatment outcomes and best practices. METHODS: Retrospective review of 504 dental records of children receiving comprehensive dental treatment under general anesthesia at children's hospitals in Boston between 1990-1992 and in Washington, DC, between 1994-1998, were undertaken. Data regarding restoration outcomes were evaluated using chi square tests with correction for continuity. Only records of patients who returned for follow-up at least six months after their rehabilitations were evaluated. T-tests were performed on parametric data. RESULTS: Two-hundred and forty-one (48%) of the records were evaluated. Stainless steel crowns (SSCs) had significantly lower failure rates than amalgams (P<0.001, chi2=63). The highest failure rates were seen in composites (P<0.001, chi2=112) and composite strip crowns (P<0.001, chi2=121). CONCLUSIONS: SSCs are the most reliable restorations while composite restorations are the least durable. Failure of restorations appears to be related to follow-up length.

Adolescent↗
PubMed1998

Scanning acoustic microscopy study of titanium-ceramic interface of dental restorations.

Failures that occur in titanium-ceramic restorations are of concern in clinical dentistry. The purpose of this study was to nondestructively characterize the internal cracks and nonadherent defects at the titanium-porcelain interface using scanning acoustic microscopy. Titanium samples coated with porcelain without a bonding agent, with sputter coated palladium or chromium as an oxygen diffusion barrier on the titanium, and with the use of a porcelain bonding agent (control group) were compared. The scanning acoustic microscopy analyses were correlated with four-point bending test results. The group that was initially coated with palladium had fewer interfacial defects and a higher load to failure than the control group, and the group that did not contain the bonding agent had a higher void area and a lower load to failure than the control group. The use of chromium produced no differences from the control group. Samples after a four-point bending test were also analyzed by scanning electron microscopy. The scanning electron microscopy was not able to characterize interfacial defects at the fractured titanium-ceramic interface for some of the samples. The validity of nondestructive analysis at the Ti-ceramic interface using scanning acoustic microscopy was demonstrated in this study.

Chromium↗
PubMed1998

Tunnel restorations in permanent teeth. A 7 year follow up study.

The aim of the study was to perform a long-time evaluation of tunnel restorations made in a general dental practice concerning survival time and type of failures. 267 Class I (87%) and II (13%) tunnel restorations in permanent teeth on 193 patients--mostly teenagers and young adults--were evaluated at annual recalls. The observation time-span was 1-7 years. The restoration material was a conventional glass ionomer cement in Class I tunnels and a silver cermet glass ionomer cement in Class II tunnels. The yearly failure rate was 7% and the 50% survival time was 6 years. The reasons for replacement were: marginal ridge fracture (41%), recurrent caries (40%) and cavitation in approximal enamel (19%). No differences in failure rate between Class I and II tunnels could be seen, but recurrent caries was more frequent in Class I tunnels. Restorations made during the second year of the study were more successful, indicating a learning effect. Class I tunnel restorations in general practice can be an alternative to conventional Class II restorations with narrow indications, i.e. patients with relatively low caries activity, small approximal lesions in combination with small demineralization zones in the enamel wall.

Adolescent↗
PubMed2006

Multilevel modelling of clustered grouped survival data using Cox regression model: an application to ART dental restorations.

In some controlled clinical trials in dental research, multiple failure time data from the same patient are frequently observed that result in clustered multiple failure time. Moreover, the treatments are often delivered by more than one operator and thus the multiple failure times are clustered according to a multilevel structure when the operator effects are assumed to be random. In practice, it is often too expensive or even impossible to monitor the study subjects continuously, but they are examined periodically at some regular pre-scheduled visits. Hence, discrete or grouped clustered failure time data are collected. The aim of this paper is to illustrate the use of the Monte Carlo Markov chain (MCMC) approach and non-informative prior in a Bayesian framework to mimic the maximum likelihood (ML) estimation in a frequentist approach in multilevel modelling of clustered grouped survival data. A three-level model with additive variance components model for the random effects is considered in this paper. Both the grouped proportional hazards model and the dynamic logistic regression model are used. The approximate intra-cluster correlation of the log failure times can be estimated when the grouped proportional hazards model is used. The statistical package WinBUGS is adopted to estimate the parameter of interest based on the MCMC method. The models and method are applied to a data set obtained from a prospective clinical study on a cohort of Chinese school children that atraumatic restorative treatment (ART) restorations were placed on permanent teeth with carious lesions. Altogether 284 ART restorations were placed by five dentists and clinical status of the ART restorations was evaluated annually for 6 years after placement, thus clustered grouped failure times of the restorations were recorded. Results based on the grouped proportional hazards model revealed that clustering effect among the log failure times of the different restorations from the same child was fairly strong (corr(child)=0.55) but the effects attributed to the dentists could be regarded as negligible (corr(dentist)=0.03). Gender and the location of the restoration were found to have no effects on the failure times and no difference in failure times was found between small restorations placed on molars and non-molars. Large restorations placed on molars were found to have shorter failure times compared to small restorations. The estimates of the baseline parameters were increasing indicating increasing hazard rates from interval 1 to 6. Results based on the logistic regression models were similar. In conclusion, the use of the MCMC approach and non-informative prior in a Bayesian framework to mimic the ML estimation in a frequentist approach in multilevel modelling of clustered grouped survival data can be easily applied with the use of the software WinBUGS.

Adolescent↗
PubMed1998

Microscopic and energy dipersive x-ray analysis of surface adaptation of dental cements to dental ceramic surfaces.

STATEMENT OF PROBLEM: Clinical failure rates reported for acid etched/resin-bonded ceramic restorations are significantly lower than those reported for restorations luted with traditional cements. This improved clinical performance may be associated with greater adaptation of the resin cements to the ceramic surfaces. PURPOSE: The objective of this study was to determine whether the use of resin cements accompanied by acid etching results in improved adaptation when compared with the use of zinc phosphate or glass ionomer cements. RESULTS: The results of this experiment indicate that superior adaptation of cement to ceramic is produced by acid etching and luting with resin cement. In addition, the results lead to the hypothesis that the high clinical failure rates reported for zinc phosphate or glass ionomer luted restorations are due either to incomplete adaptation or to failure within the cement. CONCLUSION: The findings indicate that the use of resin cements accompanied by acid etching of the ceramic surface is the preferred technique for clinical placement of all-ceramic restorations.

Acid Etching, Dental↗
PubMed1999

The theory and practice of internal 'tunnel' restorations: a review of the literature and observations on clinical performance over eight years in practice.

The tunnel or 'internal' restoration to restore an approximal caries lesion was first described in 1984. The technique allows the operator to conserve the important external anatomical features of the tooth, thereby saving considerable clinical time while leaving relatively little of the material externalized. The development of a new generation of glass-ionomer materials with higher flexural and compressive strengths appears to satisfy the main objective of carious dentine replacement facilitated by a 'keyhole' internal preparation. The long-term clinical evaluation of these materials is difficult since new formulations are being continually developed. The literature was reviewed. Clinical cases restoring approximal caries lesions in permanent molars and premolars were observed in a private practice. Over the course of eight years 60 tunnel restorations were placed in 48 regularly attending patients. The materials used in both total and partial tunnel restorations were Ketac Silver, Hi-Dense and Fuji IX. At eight years a failure rate of 15% was seen in the 50 restorations observed at last dental examination. The findings suggest that modern tunnel techniques may offer a restorative technique worthy of consideration in treating primary approximal caries lesions.

Adolescent↗
PubMed2006

Clinical failure of class-II restorations of a highly viscous glass-ionomer material over a 6-year period: a retrospective study.

OBJECTIVES: The aim of this retrospective clinical study was to evaluate the performance of high-viscosity glass-ionomer cement (GIC) class-II restorations over 6 years of clinical service. METHODS: All class-II GIC restorations made in 1996 and 1997, in regular attending adult patients of a general dental practice were selected. Restorations made for temporary function were excluded, as were those restorations not made using the main study material: Fuji IX GP (GC). Failures were recorded where replacement or repair had occurred. Radiographs were evaluated where available. RESULTS: The final study group consisted of 116 class-II restorations in 72 patients (33 males, 39 females). Distribution of restorations was: 30 MO, 40 DO, 46 MOD. Until 18 months no failures were observed. From 18 to 42 months survival dropped to 93%. After 42 months failure rate increased and at 72 months survival was only 60%. In all but one case the recorded reason for replacement or repair was gross loss of GIC in proximal areas. No restorations failed because of occlusal wear or isthmus-fractures. On radiographs, progressive loss of GIC material in proximal areas, just below contact areas, was commonly observed. In absence of adjacent teeth no loss of GIC material was observed at proximal surfaces. SIGNIFICANCE: Rising failure rate of class-II high-viscosity GIC restorations, due to proximal breakdown was observed. We hypothesize that caries-like loss of material as seen on radiographs contributes to this phenomenon. Presence of proximal contacts seems to promote disintegration of cement.

Adult↗
PubMedDate not supplied

Influence of different transitional restorations on the fracture resistance of premolar teeth.

Controversy exists over the most favorable material and type of restoration to be used to transitionally restore teeth destined to be crowned. This in vitro study uses fracture resistance testing to compare eight different transitional restorations in maxillary premolars. Ninety sound maxillary premolars were randomly selected and allocated to nine groups, each comprising 10 teeth. One group remained unrestored and was used as the control. Teeth in the remaining groups were prepared to a standard cavity form using: a copy milling process removing the palatal cusp. Restorations were placed using amalgam with dentin pins and cavity varnish; amalgam with an amalgam bonding agent; resin composite with dentin pins and a dentin bonding agent; resin composite with a dentin bonding agent only; resin-modified glass ionomer with dentin pins; resin-modified glass ionomer cement alone and cermet with dentin pins and cermet alone. Each restored tooth was then subjected to axial loading via a bar contacting the buccal and restored palatal cusps until failure of the restored tooth occurred. The mean load-to-fracture values were statistically compared and the modes of failure recorded. It was found that the choice of restorative material and type of restoration had little effect on the fracture resistance of the restored tooth with the exception of those teeth restored with reinforced glass ionomer cement alone, which exhibited a significantly lower resistance to fracture than the other restored teeth. However, the choice of restorative material/technique did influence the mode of failure. Failure in teeth restored with resin-modified glass ionomer cement alone produced the least damage to the remaining tooth tissue when failure occurred. Consequently, this material may offer the most favorable range of properties for the transitional restoration of extensively broken-down maxillary premolar teeth destined to be crowned. Furthermore, the findings of this study fail to support the use of dentin pins in the placement of bonded build-up restorations.

Analysis of Variance↗
PubMed2001

One-year retrospective clinical evaluation of hybrid composite restorations placed in United Kingdom general practices.

OBJECTIVE: The purpose of this study was to assess Pertac II restorations placed in general dental practice. METHOD AND MATERIALS: A total of 86 restorations (14 Class I, 10 Class II, 17 Class III, 5 Class IV, and 40 Class V) using a hybrid composite material (Pertac II) placed in 56 patients (mean age, 39 years) in 5 dental practices in the United Kingdom were assessed after 1 year by a trained evaluator and the dental practitioner who had placed the restoration. All the restorations were assessed for anatomic form, marginal adaptation, surface roughness, sensitivity or discomfort, gingival condition, and the presence or absence of secondary caries. RESULTS: Thirty-five (43%) restorations were placed in load-bearing situations, 9% of which were assessed as being in "heavy" occlusion. Five (6%) of the restorations were lost (all Class V restorations), 4 from premolars and 1 from a molar. Four were in wedge-shaped cavities and 1 small restoration was actually dislodged during examination. The remaining 81 (94%) restorations were found to be intact, with no secondary caries detected. A high percentage of optimal scores were recorded for both anatomic form and surface roughness. CONCLUSION: It is concluded that the evaluation demonstrated satisfactory clinical performance of Pertac II restorations after 1 year of clinical service in the wide variety of clinical situations seen in general dental practice. However, the potential for failure of hybrid composite materials in Class V situations appears high. It may be argued that clinicians who wish to use a resin-based material in a Class V situation should use a compomer or microfilled composite.

Adult↗
PubMed2002

Direct posterior restorations: clinical results and new developments.

The longevity of dental restorations is dependent on many different factors, including those related to materials, the dentist, and the patient. The main reasons for restoration failure are secondary caries, fracture of the bulk of the restoration or of the tooth, and marginal deficiencies and wear. The importance of direct-placement, aesthetic, tooth-colored restorative materials is still increasing. Amalgam restorations are being replaced because of alleged adverse health effects and inferior aesthetic appearance. All alternative restorative materials and procedures, however, have certain limitations. Direct composite restorations require a time-consuming and more costly treatment procedure and are actually only indicated for patients with excellent oral hygiene. Glass ionomers can be considered only as long-term provisional restorations in stress-bearing posterior cavities. Future treatment regimens that are made possible by the development of sophisticated preparation techniques, improved dentin bonding agents, and resin-based restorative materials will result in the therapy of more small-sized lesions rather than large restorations. The importance of indirect inlay techniques will shift more and more toward the direct restoratives. As the cavities become smaller, it is to be expected that the use of improved direct restorative materials will provide excellent longevity even in stress-bearing situations.

Bicuspid↗
PubMedDate not supplied

Early fracture resistance of amalgapin-retained complex amalgam restorations.

Amalgapins are susceptible to early fracture during matrix removal and carving. The purpose of this study was to examine the early fracture resistance of amalgapin-retained restorations using a spherical amalgam alloy, an admixed amalgam alloy, a combination of admixed alloy over the spherical alloy, and a recently introduced modified spherical amalgam alloy. Four amalgapin channels with a diameter of 1.4 mm and depth of 2 mm were prepared in cylinders of Macor, a machinable ceramic material. The amalgapins were hand condensed, and the bulk of the restoration was mechanically condensed. In the group using the combination of alloys, 800 mg of spherical alloy was condensed into the amalgapins and over the floor of the preparation. The admixed alloy was then condensed over the spherical alloy to build up the bulk of the restoration. Using an Instron Universal Testing Machine, the restorations were tested to shear failure at an average of 15.8 +/- 1.3 minutes after the initiation of trituration of the amalgam alloy. A metal ring was placed around the restoration and pulled 90 degrees to the long axis to simulate matrix band removal. Data were analyzed using Kruskal-Wallis procedures. The fracture resistance of the spherical alloy group and the spherical/admixed group were significantly higher than admixed or Tytin FC. All fractures occurred in amalgam at the entrance to the amalgapin channel. The combination of spherical and admixed amalgam alloys in a restoration may reduce the potential for early dislodgment while allowing additional time for carving.

Dental Alloys↗
PubMed2003

Wear of dental resin composites: insights into underlying processes and assessment methods--a review.

Given the increased aesthetic demands of patients, along with improvements in the formulation of resin composites, the ability of these materials to bond to tooth structures, and concerns about dental amalgam fillings, the applicability of resin composites in dentistry has become increasingly widespread. As resistance to wear represents an important factor in determining the clinical success of resin composite restoratives, the aim of this article was to define what constitutes wear; the major underlying phenomena involved in this process-adhesion, abrasion, fatigue, and corrosion-being described. Discussions were also focused on factors that contribute both to the magnitude and minimization of resin composite wear. Finally, insights were included on both in vivo and laboratory studies used to determine wear resistance.

Animals↗
PubMed2002

Can modern restorative procedures and materials reliably seal cavities? In vitro investigations. Part 1.

Secondary caries, marginal discoloration and marginal gap/fracture account for a significant majority of clinical diagnoses of restoration failure and reason for restoration replacement. These failures occur at the interface between the restoration and the cavity preparation. It is an underlying belief, or at least an underlying assumption of the dental profession, that improving the seal between a restorative material and tooth structure will reduce the frequency of such occurrences, which will in turn lead to enhanced restoration longevity. This paper reviews the current status of in vitro literature regarding the ability of modern restorative materials and techniques to reliably seal cavity preparations. In addition, methodology for accomplishing in vitro research is reviewed for the purpose of elucidating trends, areas of interest and controversial topics.

Composite Resins↗
PubMed1999

Clinically relevant approach to failure testing of all-ceramic restorations.

STATEMENT OF PROBLEM: One common test of single-unit restorations involves applying loads to clinically realistic specimens through spherical indenters, or equivalently, loading curved incisal edges against flat compression platens. As knowledge has become available regarding clinical failure mechanisms and the behavior of in vitro tests, it is possible to constructively question the clinical validity of such failure testing and to move toward developing more relevant test methods. PURPOSE: This article reviewed characteristics of the traditional load-to-failure test, contrasted these with characteristics of clinical failure for all-ceramic restorations, and sought to explain the discrepancies. Literature regarding intraoral conditions was reviewed to develop an understanding of how laboratory testing could be revised. Variables considered to be important in simulating clinical conditions were described, along with their recent laboratory evaluation. CONCLUSIONS: Traditional fracture tests of single unit all-ceramic prostheses are inappropriate, because they do not create failure mechanisms seen in retrieved clinical specimens. Validated tests are needed to elucidate the role(s) that cement systems, bonding, occlusion, and even metal copings play in the success of fixed prostheses and to make meaningful comparisons possible among novel ceramic and metal substructures. Research over the past 6 years has shown that crack systems mimicking clinical failure can be produced in all-ceramic restorations under appropriate conditions.

Cementation↗