The Use of Hall's Technique Preformed Metal Crown (HTPMC) by Pediatric Dentists in Malaysia.

INTRODUCTION: Hall's technique preformed metal crown (HTPMC) has been used widely by pediatric dentists in developed countries as a new approach for managing decayed primary molars without local anesthesia, caries removal, and tooth preparation. Currently, inadequate information is available regarding the implementation of this technique (HTPMC) in Malaysia. This study is aimed at evaluating the implementation of HTPMC by Malaysia's pediatric dentists and identify the co-occurrence frequencies of the HTPMC implementation with the respondents' demographic profile. MATERIALS AND METHODS: A cross-sectional questionnaire-based research was conducted among 65 pediatric dentists in Malaysia. Online questionnaires were distributed to the pediatric dentists employed at public hospitals (MOH) and universities in Malaysia. RESULT: It was found that over half of the respondents (65.6%) employed HTPMC. The analysis of the co-occurrence network frequency revealed that a high frequency of female pediatric dentists who were within the age group of 31-40 years old had fulfilled their postgraduation overseas and was employed in the university mainly applied HTPMC. CONCLUSION: The application of HTPMC among respondent pediatric dentists in Malaysia was high. However, most respondents considered HTPMC a treatment option only to manage carious primary molar rather than a treatment of choice.

A survey of practices of tunnel preparation among dentists who attended the 100th FDI Annual World Dental Congress.

AIM: To study the practice of tunnel restoration (TR) among dentists who attended the 100th World Dental Federation (FDI) Annual World Dental Congress (AWDC). METHODS: An anonymous questionnaire was administered to a sample of 150 dentists who attended the 100th FDI AWDC in 2012. The participants were asked about TR and their practice of TR. They were also asked to provide their years of dental practice and the countries in which they received their dental training. RESULTS: Fifteen respondents were not performing restoration, and they were excluded from analysis. Most respondents (123/135) practiced general dentistry. Their basic dental training was from 46 countries and regions. Most of them (n = 117, 87%) knew about TR, and 53% (n = 71) practiced it. There were 12 dentists (9%) who had performed more than 10 TRs in the previous 12 months. Practice of TR among dentists who graduated more than 10 years previously was more common (odds ratio 5.87-5.98) than those who graduated <3 years previously. CONCLUSIONS: The current study found that about half of the surveyed dentists practiced TR, although most of them knew about it. Tunnel restoration was performed more frequently among dentists who had more than 10 years of clinical experience.

Learning curves: what do dental students learn from repeated practice of clinical procedures?

It is generally accepted that repetition of procedures is necessary to develop clinical skill in dentistry. Although there is a rich empirical research tradition in medicine establishing competency levels for new procedures, investigations of the shape of learning curves for clinical techniques are rare in dental education. Data were reviewed from three classes (n=465) of students at the University of the Pacific Arthur A. Dugoni School of Dentistry in seventeen clinical skills in five departments for which test case (independent performance) data were available. It was hypothesized that a learning curve would be observed with gradually rising scores as a function of amount of repeated test case work and general practice experience. Other factors, such as faculty ratings and clinical GPA, could be expected to modify this curve. No evidence was found that test case performance was affected by number of previous test cases, number of practice (ungraded) procedures previously completed, faculty ratings of technical skill in the discipline by quarter, faculty ratings of patient management and of clinical judgment competencies, overall clinical GPA, and performance on initial licensure examinations. The absence of a pattern showing that amount of prior experience improves clinical performance raises questions about the practice of setting "requirements" for graduation and challenges dental educators to better explain the presumed relationship between practice and performance and the validity of clinical evaluation of performance based exclusively on the objective technical quality of work samples. The literature on learning curves and on competency-based education offer alternative insights into what students are actually learning but schools are failing to measure in the clinical experience.

Factors associated with the longevity of resin composite restorations.

This study investigated factors associated with the longevity of resin composite restorations, which were placed in 97 patients (mean age of 58 years) by 24 dentists in Nagasaki University Hospital between 1995 and 2005. All patients were under the charge of the principal investigator (SK) and most of them had been regularly checked up for up to 11 years. A total of 503 resin composite restorations (433 by SK and 70 by the other dentists) were analyzed by the Kaplan-Meier and the Cox proportional hazards model. Ten-year survival rates were 84.2% for SK and 71.8% for the others, showing a significant difference. Although the retreatment risk had a great influence on the survival time, gender and age at placement did not have. There were no significant differences in survival between conventional 2-step etch-and-rinse, 2-step self-etch adhesives with and without prior enamel etching. Cavity type had a significant influence, whereas tooth type had no effect.

The survival of Class V restorations in general dental practice. Part 1, baseline data.

OBJECTIVE: Evidence on the survival of different restorations in general practice is scarce and so to address this need, a study was designed to monitor the outcome of Class V restorations placed in UK general practices. DESIGN: Prospective longitudinal cohort multi-centre study. SETTING: UK general dental practice. MATERIALS AND METHODS: Ten UK dentists each placed 100 Class V restorations and recorded selected clinical information at placement and at recall visits on record cards. Dentists selected materials and techniques which they felt appropriate to each clinical situation. RESULTS: Data cards for 11 restorations were incorrectly completed or information was missing leaving 989 for analysis. The majority of restorations were placed in patients between 51 and 60 years of age, in canines or premolars (68.4%) and under private contract (63%). Composite (40.85%) and compomer (23.46%) were the most frequently placed materials overall but were not the most frequently placed restorative by some dentists. CONCLUSIONS: Different dentists use different methods to manage Class V lesions but each dentist tends to use one restorative material predominantly. There is a degree of overlap among practitioners in the materials which they employ, but clear preferences were displayed in the materials used and handling techniques.

Long-term survival of Cerec restorations: a 10-year study.

This clinical retrospective study assessed the longevity of CAD-CAM ceramic restorations (Cerec) inserted into the cavities of 95 patients in a private practice in Berlin, Germany. Three hundred and eight ceramic restorations were inserted into cavities in the posterior teeth of 95 patients between 1992 and 1994. One operator placed all restorations in a single sitting. Seventy-four patients, including 226 restorations, returned to the practice for a final examination at the end of 10 years. Reasons for non-attendance include relocation (15), death (2) and personal reasons (4). Again, all examinations were performed by a single examiner, however, not the same dentist who initially treated the patients. Out of the 226 restorations, 39 had been inserted in Class I cavities and 187 in Class II cavities (84 two-surfaces, 103 three or more surfaces). In the latter group, one cusp was replaced in 20 cases and two cusps in three cases. All the restorations were fabricated using Cerec 1 (46 Dicor, 180 Vita Mark II) and cemented adhesively with Vita Cerec Duo Cement in combination with Syntac Classic under a rubber dam. Kaplan-Meier survival analysis was calculated under the following failure-criteria: (1) secondary decay, (2) any kind of loss of the restoration, (3) fracture of the restoration, (4) tooth fracture and (5) marginal gap reaching dentin or base material. For statistical analysis, SPSS 12.0 was used. The survival rate was 94.7% (12 failures) after five years and 85.7% (23 failures) after 10 years. The results of the current study show that the survival rate of Cerec 1 restorations, as applied in this study, are comparable with the survival rates of cast gold restorations.

Influência do método de preparo cavitário, alta rotação e laser de Er: YAG, sobre a espessura da camada híbrida de diferentes sistemas adesivos, com diferentes filosofias adesivas / Influence of cavity preparation method, high speed turbine and Er: YAG laser, on hybrid layer thickness of different adhesive systems

O objetivo deste estudo foi promover uma comparação entre as espessuras de camadas híbridas formadas entre os sistemas adesivos Scotchbond Multi-Uso Plus, Single Bond 2, Prime & Bond 2.1 e Xeno III, e a superfície dentinária, preparada com dois métodos de preparo cavitário, a ponta diamantada montada em turbina de alta rotação, e o laser de Er:YAG, utilizado com dois parâmetros de energia (200 e 400 mJ) e dois parâmetros de freqüência (4 e 6 Hz). Para a realização deste experimento, foram realizados tratamentos superficiais com os dois métodos descritos em fragmentos de dentina superficial aplainada, retirados de vinte terceiros molares humanos recém-extraídos, seguido de preparo da dentina com os sistemas adesivos. Após a aplicação e fotoativação de uma camada de compósito sobre a dentina preparada, os corpos de prova foram cortados, polidos e preparados para visualização em MEV, meio pelo qual foram realizadas cinco medidas da espessura da camada híbrida formada em cada corpo de prova. Os resultados obtidos foram tratados estatisticamente por ANOVA e teste de Student-Newnan-Keuls, em um nível de significância de 95%, e por Kruskal Wallis e Mann Whitney, também em um nível de significância de 95%, através do programa SPSS for Windows release 5.0. A análise foi realizada levando-se em consideração dois fatores de estudo, a presença ou não de camada híbrida e a espessura da camada híbrida. Em relação ao fator espessura da camada híbrida, quando se avaliou o tipo de preparo realizado, a análise estatística por ANOVA e Student-Newman-Keuls levou a formação de quatro grupos homogêneos, sendo Grupo I (ponta diamantada) > Grupo II (Laser 200 mJ / 4 Hz) = Grupo III (Laser 200 mJ / 6 Hz) > Grupo IV (Laser 400 mJ / 4 Hz) > Grupo V (Laser 400 mJ / 6 Hz). Quando se avaliou o tipo de sistema adesivo utilizado, não se encontrou diferença estatisticamente significante. Em relação ao fator presença de camada híbrida, quando se avaliou o tipo de preparo realizado, a análise

Tunnel or saucer-shaped restorations: a survival analysis.

The aim of the present effectiveness trial was to compare the survival of restorations placed in saucer-shaped cavities to that of restorations placed in tunnel preparations. Ten operators placed a total of 85 tunnel and 97 saucer-shaped restorations. The dentinal part of the tunnel was restored by resin-modified glass ionomer cement. The remaining part of the tunnel was restored by composite resin using an adhesive technique. Composite resin was used to restore the saucer-shaped cavities. The restorations were assessed clinically and radiographically for up to 79 months, with a mean observation time of 28.8 months for tunnel, and 30.3 months for saucer-shaped restorations. The survival proportion of the tunnel restorations was 46%, and the survival proportion for the saucer-shaped restorations was 76%. A main reason for failure of the tunnel restorations was fracture of the marginal ridge (24% after 24 months). Caries development in relation to the restoration was significantly higher for tunnel restorations compared with saucer-shaped restorations (41 and 19%, respectively, after 24 months). There was no difference between the two types of restoration in marginal deterioration and caries progression in the neighboring tooth (40% after 24 months). Based on findings from the present study, it is suggested that saucer-shaped restorations should be preferred for tunnel restorations in small- and mid-sized cavities.

A clinical and microbiological study of approximal carious lesions. Part 2: efficacy of caries removal following tunnel and class II cavity preparations.

A randomized controlled clinical study was set up to assess caries removal following tunnel preparation (test group) and class II cavity preparation (control group). Sixty approximal lesions in adult posterior teeth, visible in the outer third of dentine on bite-wing radiographs, were referred for operative treatment. Initial dentine samples were taken on entry to the lesions in both groups. Following cavity preparation dentine samples were taken from beneath the marginal ridge in the tunnel group and at the cervical floor in both groups. Microbiological analysis was carried out to establish the level of infection of the dentine. The bacterial counts were high on entry to the lesions with a median log10 (CFU + 1) per sample of 3.07 (+/-1.24). Following cavity preparation bacterial counts at the cervical floor were significantly reduced in both amalgam and tunnel groups (p<0.00001). In the tunnel group, however, slightly increased bacterial counts were found beneath the marginal ridge compared to the cervical floor (p<0.01).

A clinical and microbiological study of approximal carious lesions. Part 1: the relationship between cavitation, radiographic lesion depth, the site-specific gingival index and the level of infection of the dentine.

A clinical study was carried out to assess relationship between the presence of approximal cavitation, the radiographic depth of the lesion, the site-specific gingival index and the level of infection of the dentine. Adult patients assessed as needing operative treatment and presenting with approximal lesions visible in the outer third of dentine on bite-wing radiographs were included in the study. Direct lesion depth measurements were recorded from the radiographs and the site-specific gingival index adjacent to the lesion was noted. The presence or absence of a cavity was recorded on an impression following tooth separation. During operative treatment samples of dentine were taken on entry to the lesions to ascertain the level of infection of the dentine. Visual evaluation of 54 successfully recorded impressions revealed that 85% were cavitated. Cavitated lesions were found to have higher site-specific gingival index scores compared to non-cavitated lesions (p = 0.03). The probability of cavitation was greater for lesions >0.5 mm from the enamel-dentine junction on bite-wing radiographs (p<0.01). The level of infection of the dentine was significantly higher for cavitated lesions than for non-cavitated lesions (p = 0.02). However, the non-cavitated lesions were still infected.

In vitro evaluation of five alternative methods of carious dentine excavation.

This in-vitro, split-tooth study aimed to evaluate the efficiency (time taken) and effectiveness (quantity of dentine removed) of four techniques of carious dentine excavation (bur, air-abrasion, sono-abrasion and Carisolv gel) compared to conventional hand excavation. Eighty freshly extracted human molars were assigned to four experimental groups (n = 20), sectioned longitudinally through occlusal lesions and pre-excavation colour photomicrographs obtained. Using the natural autofluorescence of carious dentine (detected using confocal laser scanning microscopy) as an objective and reproducible guide, carious dentine removal was assessed in each half of the split tooth sample, comparing hand excavation to the test method. The time taken to reach a cavity floor that was hard to a dental probe was noted and final colour photomicrographs were taken. From the results, it was concluded that bur excavation was quickest but overprepared cavities relative to the autofluorescent signature, whereas Carisolv excavation was slowest but removed adequate quantities of tissue. Sono-abrasion tended to underprepare whereas air-abrasion was more comparable to hand excavation in both the time and amounts of dentine removed. Conventional hand excavation appeared to offer the best combination of efficiency and effectiveness for carious dentine excavation within the parameters used in this study.

Qualitative and quantitative determination of dental amalgam restoration volume.

STATEMENT OF PROBLEM: Volume of tooth structure replaced by an existing restoration, as assessed by visual and radiographic examination, is one diagnostic measure used by dental practitioners and dental insurance agencies to determine the relative need to restore a tooth with a full-coverage cast restoration. However, use of these methods has not been validated. PURPOSE: This study compared the volume of a range of dental amalgam restorations placed in typodont teeth, as estimated by dentists, dental students and laypersons, with the actual volume of each restoration. METHODS AND MATERIAL: Sixty subjects (20 dental school faculty, 20 dental students, and 20 clerical staff [laypersons]) participated. After reviewing photographic images of typodont teeth with mesial-occlusal-distal dental amalgam restorations, subjects estimated the volume of each restoration using various restorations on different teeth as a percentage of its tooth's coronal volume. The actual volume of each dental amalgam restoration and that of the coronal portion of the prepared teeth was calculated with a volumetric displacement technique. The single sample 2-sided t test with a.05 level of significance was used to evaluate the null hypothesis (H0 ): The survey participant's estimates of each restoration's percentage volume are the same as the measured volume values versus the alternative hypothesis (H1 ): estimates differed from the measured volume values. One-way analysis of variance was used to determine the significance of any difference between the estimates of the 3 survey test groups. RESULTS: Average volumes reported by all 3 groups were significantly different than the measured volume values (P <.05). Experience and dental training did not significantly affect a participant's ability to evaluate restoration volumes with greater accuracy. Results reported by dentists, dental students, and laypersons were not significantly different (P >.05). CONCLUSIONS: The volume of a restoration is inaccurately assessed by visual and radiographic examination.

Effects of dentin depth and cavity configuration on bond strength.

During polymerization of resin composites, shrinkage stresses compete with resin-dentin bonds in a manner that can cause failure of the bond, depending upon the configuration of the cavity, its depth, and the restorative technique. The hypothesis tested in this study was that the effect of cavity configuration (C) and remaining dentin thickness (RDT) influence resin bond strength to the dentin of Class I cavity floors. The occlusal enamel was ground to expose a flat superficial dentin surface as a control (superficial dentin, C-factor = 1) in human extracted third molars. Cavities 3 mm long x 4 mm wide were prepared to a depth 2 mm below the ground dentin surfaces (deep dentin within cavity floor, C-factor = 3). To assess the relationship between C-factor and RDT, we removed the walls of cavities, making a deep flat surface for bonding (deep dentin, C-factor = 1). The teeth were restored with either Clearfil Liner Bond II (LB II), One-Step (OS), or Super-Bond D Liner (DL), followed by Clearfil Photo Posterior resin composite. After 24 hrs' storage in water, the teeth were sectioned vertically into 3 or 4 slabs (0.7 mm thick) and trimmed for the micro-tensile bond test so that we could determine the strength of the resin bonds to the pulpal floor. All groups gave high bond strengths to superficial dentin, but OS and DL gave significantly lower bond strengths to flat deep dentin when the C-factor was 1. When the C-factor was increased to 3 by the creation of a three-dimensional cavity preparation, the bond strengths of all materials fell (range, 21 to 35%), but the difference was significant (p < 0.05) only with DL. SEM observations of failure patterns showed that specimens with high bond strengths tended to exhibit cohesive failures within the hybrid layer, while specimens exhibiting low bond strengths showed failures at the top of the hybrid layer. Some adhesives do not bond well to deep dentin, making them more susceptible to polymerization shrinkage stress that develops in cavities with high C-factors.

The analysis of restoration survival data in split-mouth designs.

OBJECTIVE: To report methodological difficulties with restoration survival data in controlled clinical trials on Class II amalgam restorations using a split-mouth design. The advantages and disadvantages of different ways of handling these data are described. METHODS: Three statistical methods (Kaplan-Meier estimation, logistic regression with random component and Friedman's statistic) are compared using data from a controlled clinical trial in which cavosurface angle (regular or non-standard) and cavity wall finish (applied or not applied) determine four treatment modalities of New True Dentalloy restorations. RESULTS: In this study logistic regression with a random component yields the best interpretable results. Cavity wall finish in combination with a regular cavosurface angle is indicated as the worst and cavity wall finish in combination with a non-standard cavosurface angle as the best treatment when the criterion is replacement or not within 15 years. CONCLUSIONS: The dependency between restorations within a patient needs to be taken into account. Logistic regression with a random component may be a valuable alternative to very advanced statistical survival modelling when restricting the research question to replacement within a certain time interval is not a major problem.

Restoration of permanent teeth in young rural children in Cambodia using the atraumatic restorative treatment (ART) technique and Fuji II glass ionomer cement.

UNLABELLED: Several recent studies have demonstrated the success of the ART (atraumatic restorative treatment) technique under field conditions in developing countries. The ART technique involves removal of caries using only hand instruments, and placing a glass ionomer cement (GIC) restoration. OBJECTIVES: To estimate the longevity of Fuji II GIC ART restorations placed in permanent teeth by dental nurse students under field conditions in rural Cambodia. DESIGN: Clinical field trial. SETTING: One high school in rural Cambodia. SAMPLE AND METHODS: 53 subjects between the ages of 12 and 17 who had dental caries were selected to participate. Subjects were randomly assigned to a dental nurse student for cavity preparation and placement of ART restorations (without cavity conditioning). RESULTS: 92.1% of the carious lesions required class I or class V restorations, and 85.4% were in the lower molars. 89 teeth were filled. At 1 and 3 years 86.4% and 79.5% of restorations were still present. Restorations were assessed by one dentist according to standard criteria. 76.3% of the restorations were judged to be successful at 1 year, and 57.9% at 3 years. CONCLUSIONS: Factors which may have affected the success rates included: the material used, technical factors, failure to condition the cavity prior to restoration, and inexperience of the operators. The results suggest that ART restorations in permanent teeth using Fuji II GIC are only moderately successful after 3 years. Better results could be expected by using a dentine conditioner in conjunction with one of the newer stronger glass ionomer cements.

Prevalence and depth of artificial caries-like lesions adjacent to cavities prepared in roots and restored with a glass ionomer or a dentin-bonded composite material.

One potential advantage of glass-ionomer materials for the treatment of root caries is their ability to release fluoride and so resist cariogenic attack. A commercially available composite material has also been reported to release fluoride which reduced caries lesions in the tooth tissue adjacent to it. The aim of this study was to assess the effectiveness of a conventional glass-ionomer restoration compared with a dentin-bonded, fluoride-releasing, composite restoration when exposed to a microbial artificial caries system. Artificial caries-like lesions produced in relation to the restorations were examined and classified either as outer (surface) lesions or as wall lesions. A split-unit experimental design allowed for within-tooth comparisons of the 2 experimental restorations at different sites on the root surface. These were either totally within the root surface or positioned at the amelo-cemental junction. Outer lesion depths were significantly (p < 0.001) shallower at all sites adjacent to the glass ionomer when compared with the composite restorations. Wall lesions were significantly (p < 0.01) more prevalent adjacent to the composite material. In addition, the cavity margin position significantly (p < 0.05) affected the incidence of wall lesions, particularly in the composite group. In conclusion, glass ionomer was successful in reducing the caries-like lesion production in the adjacent root surface. This resulted from improved marginal integrity and fluoride release from this material when compared with the composite bonding system used.

Marginal seal composition in amalgam restored teeth of varying marginal leakage.

An in vitro study was performed to ascertain the marginal seal elemental composition of amalgam restored extracted teeth of known marginal leakage. Occlusal cavities were cut in 400 caries free extracted teeth and left unlined or lined with one of 5 bases. A varnish was applied to half the cavities followed by restoration with a low copper or high copper amalgam to produce 20 restoration combinations. The teeth were stored in 1 per cent NaCl and thymol for 3 and 12 months at 20 degrees C whereafter a standard fluorescent dye marginal leakage test was performed on 320 specimens (eight teeth per treatment). Restoration combinations were grouped into 4 seal classes depending on percentage marginal seal achieved for each combination: 0-25 per cent; 26-50 per cent; 51-75 per cent and 76-100 per cent. The 80 remaining teeth (2 teeth per treatment) were fractured to expose the restoration and cavity surface, covered with marginal seal material and this was analysed by energy dispersive X-ray analysis. Elemental seal composition was compared to percentage marginal seal achieved using ANOVA and Tukey's test with significance set at p < 0.05. Numbers of elemental analysis specimens falling into each marginal seal class was 0-25 per cent = 48; 26-50 per cent = 18; 51-75 per cent = 10; 76-100 per cent = 4. Of the 16 elements detected, nine were significantly linked to sealing/leakage: Ca, Cl, Cu, Mg, Hg, P, Ag, Sn and Zn. The findings have a bearing on the improved longevity of amalgam restorations.

Marginal morphology of Class V composite restorations.

PURPOSE: To evaluate the morphology of enamel and dentin margins of Class V restorations filled with different resin composites and glass ionomer cements by SEM examination of replicas. Microleakage was also evaluated between the restorative materials and dentin and enamel at different levels. MATERIALS AND METHODS: Non-retentive Class V cavities were prepared in extracted third molars on buccal and lingual surfaces at the CEJ level. Each material was used according to manufacturer's directions. Immediately after finishing, an impression of each restoration was made using a polyvinylsiloxane material to obtain an epoxy resin replica. Each replica was inspected under SEM to evaluate the morphology of the margin along the cervical-dentin and incisal-enamel junctions. Each tooth was then stored in dye solution (erythrosin B) for 24 hours. First an evaluation was made along the restoration margins to evaluate circumferential leakage. After longitudinal sectioning, leakage was calculated along the cavity wall in dentin and at the enamel interface (longitudinal leakage). RESULTS: Enamel margins were characterized (SEM) by prism fractures around restorations along with enamel chips and overhangs. These lesions were observed in about 30% of the samples. Dentin margins showed gaps along the dentin-bonding agents and fractures in the bonding agent/composite interface. Glass ionomers showed similar but fewer lesions both at enamel and dentin interfaces.

Smooth coronal surface, resin restoration and microleakage.

The space between the resin and the cavity walls has always become interesting to search. The aim of this study was to evaluate any differences on leakage values of Class 5 type resin restorations prepared on surrounding surfaces of the tooth crown. Ninety human teeth were prepared as Class 5 cavities on buccal, lingual, mesial and distal surfaces and were randomly divided into groups for bevelling, groove preparation and as control. The subgroups were arranged as fluoride gel and/or sealant applications. Fluoride gel was applied following the cavity preparations. Sealant was applied over composite resin restorations. Treated teeth were thermocycled and immersed into dye solution for 96 hours. The restorations were evaluated in a stereo-microscope following the sectioning. Bevelling of the cavosurfaces and/or preparation of a groove addition to cavity procedures did not make any difference on the microleakage scores of the restorations done on either surfaces statistically.