Assessment of the efficiency of dental excavation methods using laser speckle imaging.

This paper introduces a novel application of the laser speckle technique in dentistry, focusing on assessing the efficiency of dental excavation methods used to remove decayed tooth structure. The aim is to evaluate the efficiency of two chemo-mechanical agents and the high-speed drill using the laser speckle technique, which offers objective, non-invasive, and real-time evaluation capabilities. Extracted human primary molars with active occlusal carious lesions were sectioned into three parts, with each part allocated to one of three groups: Group 1 (Brix3000®), Group 2 (Papacarie DUO®), and Group 3 (High-speed drill mechanical caries removal). Caries removal was performed using the designated agent or method for each group. After caries excavation, speckle imaging using a 632.8 nm laser was conducted. Additionally, SEM was used to acquire micro-photographs of the surface morphology of the treated samples. The findings reveal insights into the comparative efficiency of the three dental excavation agents and methods using the laser speckle technique. The speckle parameters extracted from speckle patterns generated by treated teeth provide valuable information for evaluating the performance of the excavation methods. The scanning electron microscopy images also offer detailed visual evidence to support the analysis. This paper demonstrates the potential of the laser speckle technique for assessing the efficiency of dental excavation methods. The objective, non-invasive, and real-time evaluation provided offers advantages over subjective visual assessment and manual measurements.

Impact of self-assessment on dental student's performance in pre-clinical conservative dentistry course.

BACKGROUND: Self-assessment (SA) is an interactive course that endorses the accomplishment of learning objectives through learners' identification of insufficiencies in their didactic knowledge and pre-clinical skills. This study was planned to determine whether there is any improvement in the faculty assessment (FA) score following the implementation of SA in the Pre-clinical Conservative Dentistry Course. METHODS: Fifty-four first-semester dental students were given an introductory lecture followed by a demonstration for Class I Cavity Preparation in typhodont mandibular first molar. At the end of the demonstration, the Scoring Rubric (SR) was explained point-wise in the prepared cavities. During the next session, all students performed Class I cavity preparation and they were given an assessment sheet to enter their scores (SA1). All teeth were evaluated by the Grading Faculties in a blinded manner (FA1). Each participant was explained the difference in their respective SA1 from FA1 and their queries were resolved individually. During the next sessions, Students and Grading Faculties followed the same protocol and scores were recorded as SA2, FA2, SA3 and FA3. RESULTS: The mean score of SA1 was significantly higher than that of FA1 (p < 0.001). However, no significant difference was obtained between SA and FA in the second (p = 0.352) and third (p = 0.434) assessments. In contrast with first assessment, mean marks obtained in FA were higher compared to SA in both second and third assessments. There was a statistically significant improvement in mean marks obtained by the students over time (p < 0.001). CONCLUSION: SA endorsed student-faculty communication and enhanced student's poise and technical skills in operative pre-clinical dentistry.

Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study.

AIM: The aim of the current investigation was to evaluate the marginal microleakage of various esthetic restorative materials applied to primary teeth. MATERIALS AND METHODS: A total of 75 noncarious primary molars that were removed for orthodontic intervention and teeth nearing exfoliation were chosen. One millimeter (mm) above the cementoenamel junction, on the buccal surface of the teeth, Class V cavities were prepared. William's graded periodontal probe was used to standardize cavity preparation on all teeth. 3 mm was the cavity's length, 2 mm in width, and 2 mm in depth. The teeth were then divided into three groups (25 samples in each group) according to the type of esthetic restorative material used. Group I: Resin-modified glass ionomer cement, Group II: Ormocer, Group III: Giomer. The samples underwent 500 cycles of thermocycling, with an immersion time of 60 seconds and a well time of 15 seconds, between 5 and 55°C. The samples were submerged in methylene blue dye for 24 hours at room temperature and dried. The samples were then divided into sections and examined with a stereomicroscope. Data was recorded and statistically analyzed. RESULTS: The least marginal microleakage was found in the ormocer group (1.22 ± 0.01) followed by resin-modified glass ionomer cement group (1.31 ± 0.07) and the giomer group (1.78 ± 0.03). There was a highly statistically significant difference found between resin-modified glass ionomer cement group and the ormocer group, resin-modified glass ionomer cement group and giomer group. And no significant difference was found between the ormocer group and the giomer group. CONCLUSION: The present study concluded that there was some amount of microleakage in primary teeth in all restorative materials examined in this in-vitro investigation. However, the marginal sealing ability of ormocer was found highest compared to resin-modified glass ionomer cement and Giomer materials. CLINICAL SIGNIFICANCE: The primary reason dental restorations fail, particularly in Class V cavities, is microleakage since the margins of these restorations are typically found in the dentin or cementum. Assessing microleakage is a crucial step in determining the marginal integrity of restorative materials. Developing methods and resources that reduce the adverse effects caused by the restorative marginal seal failing would benefit from this. How to cite this article: Al Ghwainem A, Alqarni AS. Comparative Assessment of Marginal Micro Leakage of Different Esthetic Restorative Materials Used on Primary Teeth: An In-vitro Study. J Contemp Dent Pract 2024;25(1):58-61.

Evaluation of micro-CT in the assessment of microleakage under bulk fill composite restorations.

PURPOSE: To evaluate microleakage measurements using micro-CT in comparison to dye tracers in Class 2 bulk-fill composite restorations with two adhesive techniques. METHODS: 60 sound molars were prepared with Class 2 cavities having cervical margins in enamel (mesial) and in dentin (distal) and restored with Filtek Bulk Fill, using either a self-etch or total-etch technique. All teeth were thermo-cycled between 5°C and 55°C for 800 cycles and randomly exposed to three tracer dyes: 2% methylene blue, 0.5% basic fuchsin or 50% silver nitrate solutions. Teeth were sectioned mesial-distal and depth of tracer penetration was measured as a ratio of dye penetration from the cavosurface divided by total depth of the cervical floor. The silver nitrate subgroup was micro-CT scanned prior to sectioning, evaluated in 3D serial sections, and calculated volumetrically. RESULTS: Analysis of ratios for dye tracer penetration showed significantly lower values for methylene blue (0.120). Micro-CT values calculated in 3D as volume (mm³) were significantly greater in enamel for self-etch (0.060) compared to total-etch (0.020). Micro-CT volumetric analysis showed better discrimination with significantly greater leakage in enamel margins using the self-etch adhesive. CLINICAL SIGNIFICANCE: Based on this in vitro study of microleakage, micro-CT volumetric evaluation in serial digital sections improves discrimination and represents a more reliable estimate of true microleakage. In vitro study of microleakage is most useful in comparing adhesive products, but clinical application of the data is questionable.

Guided Access Cavity Preparation Using Cost-Effective 3D Printers.

INTRODUCTION: The purpose of this in vitro study was to evaluate the accuracy and precision of desktop 3D printers when fabricating stents for guided endodontics. METHODS: A stent was designed using planning software for guided endodontic access on a typodont model. Four different 3D printers were used to fabricate an identical stent, one per printer. Each stent was then used to gain access to the artificial endodontic canal on a typodont tooth and was repeated 10 times per stent by the same operator. Each of the accessed typodont teeth were scanned by a reference scanner and then imported into the inspection software. Inspection software used a best-fit alignment to automatically calculate absolute deviation at the base and tip of the bur. RESULTS: The mean distances between the planned and actual positions of the bur were low, ranging from 0.31 to 0.68 mm. Statistically significant differences were found among the 4 groups (F3,36 = 10.67, P < .05). Post hoc comparison revealed that Group Form2 significantly varied from Groups Form3 and Carbon (P < .05 and P < .05, respectively). Group Form3 obtained the most accurate and most precise axial deviations both coronally and apically. CONCLUSIONS: All of the printers tested produced stents for guided access that allowed for a high level of accuracy in obtaining access to the artificial endodontic canal, which would justify the trial of cost-effective 3D printers for guided endodontic access and necessitates further clinical research on teeth with pulp canal obliteration.

Assessment of a conservative approach for restoration of extensively destroyed posterior teeth.

OBJECTIVE: Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. OBJECTIVE: This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. METHODOLOGY: Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). RESULTS: Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. CONCLUSIONS: Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.

Assessment of a conservative approach for restoration of extensively destroyed posterior teeth

Abstract Extensive restorations in posterior teeth always bring doubts to the clinicians regarding the best protocol, mainly when structures of reinforcement were lost. Objective This study aimed to evaluate the effect of beveling on the fracture resistance and pattern of class II (MOD) restored teeth. Methodology Ninety human premolars were randomly assigned into 9 groups: CTR (control/sound); NC (cavity preparation, non-restored); RU (restored, unbeveled); RTB (restored, entire angle beveling); RPB (restored, partial/occlusal beveling); EC (endodontic access/EA, non-restored); EU (EA, unbeveled); ETB (EA, entire angle beveling); EPB (EA, partial/occlusal beveling). Teeth were restored with Esthet X resin composite and stored in distilled water for 24 h before the inclusion in PVC cylinders. The axial loading tests were performed with 500 kgF at 0.5 mm/min crosshead speed until fracture of the specimens. Fracture resistance and pattern were accessed and data were analyzed using one-way ANOVA and Tukey's HSD test (α=0.05). Results Mean (±SD) failure loads ranged from 136.56 (11.62) to 174.04 (43.5) kgF in the groups tested without endodontic access. For endodontically accessed teeth, fracture resistance ranged from 95.54 (13.05) to 126.51 (19.88) kgF. Beveling of the cavosurface angle promoted the highest fracture resistance values (p<0.05) and prevented catastrophic fractures. Conclusions Cavosurface angle beveling is capable of improving fracture resistance and pattern for both endodonticaly accessed and non-accessed teeth.

X-ray microtomography assessment of Carisolv and Papacarie effect on dentin mineral density and amount of removed tissue.

OBJECTIVE: The aim of the present study was to directly compare Carisolv and Papacarie regarding the volume of removed tissue (RT) and dentin mineral density (DMD) after excavation. MATERIALS AND METHODS: Twenty permanent molars were randomized into two groups where caries was excavated using Carisolv or Papacarie followed by removal of softened tissue by a blunt instrument. X-ray microtomography was used to scan teeth before and after excavation generating two- and three-dimensional images that were used to calculate the percentage of RT relative to baseline tooth tissue volume and DMD that was categorized into sound dentin (>1.11 g/cm3) and residual caries (≤1.11 g/cm3). The two groups were compared using t-test Fisher exact test. RESULTS: DMD was higher after Papacarie than Carisolv (mean = 1.70 and 1.14, p = .14) with higher percentage of cases with sound dentin (70 and 60%, p = 1.00). The percentage of RT was lower after Papacarie than Carisolv (7.40 and 8.95%, p = .31) with 22.95% less RT in cases that ended with sound dentin after excavation. CONCLUSIONS: There was higher DMD, more sound dentin and less RT when Papacarie was used compared to Carisolv.

Extensive Assessment of the Physical, Mechanical, and Adhesion Behavior of a Low-viscosity Bulk Fill Composite and a Traditional Resin Composite in Tooth Cavities.

OBJECTIVES: To compare the degree of conversion (DC), depth of polymerization (DP), shrinkage stress (SS), flexural strength (FS), elastic modulus (EM), and bond strength (BS) of a low-viscosity bulk fill resin composite and a paste-like traditional composite. METHODS: Tetric Evo-Flow Bulk Fill (TBF) and Empress Direct (ED; Ivoclar Vivadent) composites were used. DC (%) and FS/EM (MPa/GPa) were evaluated in bar specimens (7×2×1 mm; n=10) using Fourier-transform infrared spectroscopy and a three-point bending test in a universal testing machine (UTM), respectively. For DP and BS tests, conical cavities (n=10) were prepared in bovine dentin and restored with the composites. DP was analyzed by calculating the bottom-to-top surface microhardness ratio (BTHR), and BS (MPa) was determined by push-out testing in the UTM. SS (MPa) was measured for one increment of TBF and two increments of ED in a UTM attached to an extensometer (n=5). Data were analyzed using Student t-test and analysis of variance (α=0.05). RESULTS: TBF presented higher values than ED for DC (85.7±6.6% vs 54.2±4.9%) and BS (0.95±0.70 MPa vs 0.35±0.15 MPa). TBF values were lower than ED values for FS (76.6±16.8 MPa vs 144.9±24.1 MPa) and maximum SS (0.77±0.07 MPa vs 1.07±0.15 MPa). TBF and ED values were similar for BTHR (0.83±0.16 vs 0.84±0.08) and EM (11.5±2.8 GPa vs 12.5±2.6 GPa). CONCLUSIONS: The physical and mechanical properties of TBF, a bulk fill resin composite, were similar or superior to those of ED, a conventional composite, with the exception of FS measurements.

Comparison of efficacy of caries removal using polymer bur and chemomechanical caries removal agent: A clinical and microbiological assessment - An in vivo study.

BACKGROUND AND OBJECTIVES: Conservative caries removal has become an integral part of minimally invasive dentistry (MID). Polymer burs and chemomechanical caries removal are two feasible methods of MID. The objective of this study was to assess and compare the efficacy of polymer bur and chemomechanical caries removal agent clinically and microbiologically for selective removal of infected dentin. METHODS: A total of fifty primary second molars with occlusal decay involving dentin were selected from 25 patients aged between 5 and 9 years. They were randomly allocated to Group A (polymer bur group) and Group B (Carie-Care group) for caries removal. Completeness of caries excavation was assessed clinically with the application of caries detector dye. Dentinal samples were collected before and after caries removal and cultured in Luria-Bertani Agar, and total viable count was assessed. All the teeth after caries excavation were restored with Type 2 glass ionomer cement. The data obtained was tabulated and statistically analyzed using paired t-test and Chi-square test. RESULTS: There was a statistically significant reduction in the mean microbial count before and after treatment in polymer bur group and Carie-Care group. The reduction in mean microbial count was found significantly higher in polymer bur group compared to Carie-Care group. There was no significant association was observed between the two groups when efficacy was assessed clinically. CONCLUSIONS: Both polymer bur and Carie-Care were efficient caries removal agents when assessed clinically and microbiologically. Polymer bur was found to be more effective than Carie-Care when assessed microbiologically.

Patients' preferences for selective versus complete excavation: A mixed-methods study.

OBJECTIVES: Despite increasing evidence supporting selective caries tissue removal, the technique is not adopted by most dentists, one possible reason being that patients might reject it. We aimed to assess patients' preferences for selective versus complete excavation, and to identify predictors of this preference. METHODS: A sequential mixed-methods approach was taken. First, semi-structured focus group discussions on two convenience samples were performed. Verbatim transcripts were evaluated using content-analysis to inform quantitative study design. The subsequent survey employed convenience, snow-ball and deviant-case sampling, yielding 150 respondents. The relevance of treatment attributes (risks of nerve damage, root-canal treatment, recurrent caries, restorative complications, treatment costs, aesthetic consequences) on patients' treatment preferences was measured using case-vignettes. Dental experience and anxiety as well as patients' personality and socio-demographic details were recorded. Association of predictor variables (age, gender, education, partnership status, personality items, dental experience, anxiety) with treatment preference was assessed using regression analysis. RESULTS: Focus group participants perceived complete excavation as reliable, but feared endodontic treatment. The vast majority of survey respondents (82.7%) preferred complete over selective excavation. The preference for selective excavation was significantly increased in patients with an emotionally stable personality (p<0.001), university entrance degree (p<0.001), none or little dental anxiety (p=0.044), few dentist changes in the past (p=0.025), and who accepted that sealed lesions could progress (p<0.002). CONCLUSION: Treatment attributes, socio-demographic characteristics, personality and dental experiences shape patients' preference towards caries excavation. CLINICAL SIGNIFICANCE: Clinical decision-making regarding carious tissue removal might be affected by dentists on both an informative and an empathic level.

An initial assessment of haptics in preclinical operative dentistry training.

AIM: The purpose of this study was to assess novice student perception of haptic-based manual dexterity training. The short-term impact of haptic training in the early phase of preclinical operative dentistry education was also investigated. METHODS: Dental students performed a class II amalgam and a class III resin tooth preparation in a typodont model at baseline. The experimental group performed exercises on the manual dexterity module of the IDEA™ software using a haptic device. The exercises required removing the maximum amount of three-dimensional geometric shapes within a predetermined width and depth. Tooth preparations were repeated 2 weeks later. A questionnaire survey was given to assess the subjective evaluation of the haptic simulation exercise. RESULTS: Tooth preparations were scored regarding external outline, internal form, and integrity of adjacent tooth. Improvement of overall tooth preparation scores post-haptic use was not statistically significant compared to controls (P > 0.05). However, students found the game-feature of the haptic device made the learning experience more fun and interesting. CONCLUSION: The haptic exercises with the manual dexterity module software were not superior in improving the dexterity of students for tooth cavity preparations in short-term. Benefits of ease of use and fun learning experience can be further investigated in future studies.

In vivo assessment of caries excavation with a fluorescence camera compared to direct bacteriological sampling and quantitative analysis using flow cytometry.

The aim of this study was to assess the performance of the fluorescence camera device VistaCam iX (VC) for the control of caries excavation compared to visual assessment and bacteriological evaluation. Twenty-three patients with 32 dentinal carious lesions were included in the study. The lesions were classified using the International Caries Detection and Assessment System. Fluorescence images were taken at the surface of each lesion using the VC before excavation (stage 1), during (stage 2) and after excavation (stage 3). At each stage, dentine samples were collected. All cavities were closed after excavation using permanent fillings. Bacteria were counted within each dentine sample using flow cytometry. Significant moderate correlation between the fluorescence readings and the bacteria count was found at stage 3 (Spearman correlation coefficient rs = 0.40, p = 0.027). Area under the ROC curve (AUC) was calculated for fluorescence readings and bacteria count using the clinical status at stage 3 as a reference. AUC was 0.954 for the VC readings and 0.797 for bacteria count. Using the median bacteria count at stage 3 as a reference, the AUC for the fluorescence readings was 0.753. The results indicate that the fluorescence camera appears to be a useful supplementary tool in assessing the endpoint of caries excavation with the advantage of enabling data to be digitally visualized and stored. When an experienced dental clinician determined the excavation endpoint, the performance with respect to remaining bacteria count was good.

Micro-computerized tomography assessment of fluorescence aided caries excavation (FACE) technology: comparison with three other caries removal techniques.

BACKGROUND: The aim of this study was to determine the caries removal effectiveness (CRE) and minimal invasiveness potential (MIP) of four dentine caries removal methods. METHODS: After carious molars were scanned using micro-computerized tomography (micro-CT), dentine caries were removed by fluorescence aided caries excavation (FACE) technology, laser induced fluorescence (LIF), chemomechanical excavation (CME), and conventional excavation (CE). Micro-CT was then repeated. CRE was determined based on the volume of residual caries/initial caries (RC/IC) and the mean mineral density (MD) at the cavity floor. MIP was determined by measuring the volume of the prepared cavity/initial cavity (PC/IC). RESULTS: Among the four groups, the LIF group had the smallest RC/IC (0.08), the highest mean MD at the cavity floor (1.32 g/cm(3) ) and the highest MIP (4.47). The CME group had the highest RC/IC (0.24), the lowest mean MD (1.01 g/cm(3) ) and the lowest MIP (2.23). The CE group exhibited a more acceptable CRE (RC/IC = 0.13, mean MD = 1.21 g/cm(3) ) but had a higher MIP (3.95). Both the CRE and MIP parameters of FACE technology were the second most acceptable (RC/IC = 0.12, mean MD = 1.13 g/cm(3) , MIP = 3.20) and did not differ significantly from the most acceptable. CONCLUSIONS: FACE is an effective caries removal technology for removing infected dentine without significantly increasing cavity size.

Cost-effectiveness of one- and two-step incomplete and complete excavations.

The treatment of deep caries lesions carries significant risks for the integrity of the pulp and often initiates a cascade of re-interventions. Incomplete caries removal may reduce these risks and avoid or delay re-treatment. The present study analyzed the cost-effectiveness of one- and two-step incomplete as well as complete excavations. We used Markov models to simulate treatment of a molar tooth with a deep caries lesion in a 15-year-old patient. Retention of the tooth and its vitality as effectiveness measures as well as accruing costs were analyzed over the patient's lifetime. The model adopted a public-private-payer perspective within German health care. Transition probabilities were calculated based on literature reviews. Monte-Carlo microsimulations were performed with 6-month cycles. One-step incomplete excavation resulted in lower long-term costs and in longer-retained teeth and their vitality (means: 53.5 and 41.0 yrs) compared with two-step incomplete (52.5 and 37.5 yrs) and complete excavations (49.5 and 31.0 yrs), and dominated the other strategies in 70% to 100% of simulations. Regardless of the assumed willingness-to-pay ceiling value, one-step incomplete excavation had the highest probability of being cost-effective. Despite limited evidence levels of input data, we expect one-step incomplete excavation to reduce costs while retaining deeply carious teeth and their vitality for longer.

3D assessment of void and gap formation in flowable resin composites using optical coherence tomography.

PURPOSE: To investigate the effect of composite type and cavity size on gap and void formation using optical coherence tomography (OCT). MATERIALS AND METHODS: Class I cavities of two depths (2 mm or 4 mm; 4 mm diameter) were prepared, treated with Tri-S Bond (Kuraray Medical), and bulk filled with either Surefil SDR Flow (SF; Dentsply) or Clearfil Majesty LV (MJ; Kuraray Medical) to form four groups. After 24 h, the specimens were 3D scanned using swept-source OCT (Santec) with 1310 nm laser at a 20 kHz sweep rate. In OCT tomograms, the bonding interface and the bulk of the restorations were evaluated. The percentage values of sealed interfaces (SP) and void volume (VP) for all groups were calculated and statistically analyzed using two- and one-way ANOVA and Tukey's post-hoc test. Selected specimens were cross sectioned and observed using a scanning electron microscope (SEM) and a confocal laser scanning microscope to confirm OCT findings. RESULTS: The following values were obtained for SP and VP, respectively: SF-2mm: 92% and 0.08%; SF-4mm: 66% and 0.13%; MJ-2mm: 86% and 1.79%; MJ-4mm: 33% and 1.96%. Both composites showed a significant increase in gap formation at 4-mm cavity depth (p < 0.001). While SF showed a rather homogeneous bulk compared to MJ, cavity depth did not significantly affect the void volume fraction (p = 0.08). CONCLUSION: The flowable composite with SDR (stress-decreasing resin) technology performed better than the conventional composite; however, bulk filling a 4-mm-deep cavity will compromise the sealing of the bonding interface regardless of the type of composite. OCT is a unique method of characterizing materials and their behaviors nondestructively and precisely.

Assessment of laminate technique using glass ionomer and resin composite for restoration of root filled teeth.

OBJECTIVE: To evaluate the open laminate technique using glass ionomer cements (GIC) in association with a low shrink composite for restoring root filled premolars. METHODS: Extensive MOD cavities plus endodontic access and root filling were performed in intact extracted maxillary premolars. Three restoration types were evaluated: (1) resin composite alone; (2) resin-modified GIC (RM-GIC) open laminate plus resin composite; (3) conventional GIC open laminate plus resin composite (n=8 for all groups and tests). Three tests were conducted to assess restorations: (A) inward cusp deflection during light curing, using DCDTs; (B) fracture strength using a ramped oblique load at 45° to the long axis in a servohydraulic testing machine in comparison with intact and unrestored teeth; (C) proximal marginal leakage using methylene blue dye and the effect of thermocycling. Data were analysed using 1-way ANOVA for cuspal deflection and fracture strength and Fisher's exact test for leakage. RESULTS: Laminate restorations resulted in significantly less cuspal deflection compared with resin composite (4.2±1.2 µm for RM-GIC and 5.1±2.3 µm for conventional GIC vs. 12.2±2.6 µm for composite, P<0.001). Fracture strength was not significantly different among all groups. Failure with all restorations was predominantly adhesive at the tooth-restoration interface. The two laminate groups showed significantly better marginal seal than composite alone, but sealing ability of conventional GIC deteriorated after thermocycling. CONCLUSIONS: Laminate restoration of root filled teeth had beneficial effects in terms of reducing cuspal deflection and marginal seal, with acceptable fracture strength.

The survival of Class V restorations in general dental practice. Part 2, early failure.

OBJECTIVE: To evaluate Class V restorations placed by UK general practitioners comparing those failing or surviving after two years, and to identify factors associated with early failure. DESIGN: Prospective longitudinal cohort multi-centre study. Setting UK general dental practices. MATERIALS & METHODS: Ten dentists each placed 100 Class V restorations and recorded selected clinical information at placement and recall visits. Univariate associations were assessed between recorded clinical factors and whether restorations had failed or not at two years. Multi-variable binary logistic regression was also undertaken to identify which combination of factors had a significant effect on the probability of early failure. RESULTS: At two years, 156 of 989 restorations had failed (15.8%), with 40 (4%) lost to follow-up. Univariate analysis showed a significant association between restoration failure and increasing patient age, payment method, the treating practitioner, non-carious cavities, cavities involving enamel and dentine, cavity preparation and restoration material. Multi-variable analysis indicated a higher probability of early failure associated with the practitioner, older patients, glass ionomer and flowable composite, bur-preparation and moisture contamination. CONCLUSIONS: Among these practitioners, both analytic methods identified significant associations between early failure of Class V restorations and the practitioner, cavity preparation method, restoration material and patient's age.

Application of laser technology for removal of caries: a systematic review of controlled clinical trials.

OBJECTIVE: To evaluate the scientific evidence regarding laser technology for removal of carious tissue. MATERIAL AND METHODS: A search for literature on the effect of treatment and on economic aspects of laser technology identified 23 papers. No relevant studies on economic aspects were found. Regarding the effect of treatment, 16 papers were selected for assessment according to established criteria. RESULTS: Cavity preparation and caries excavation by erbium laser were evaluated in three studies of medium quality. The time required to remove carious tissue was evaluated in five studies assessed as being of medium quality for this outcome. In four studies the effect of laser treatment on the dental pulp was included as an outcome but, due to the short follow-up time, the quality was assessed as low. Two studies that included the longevity of the restoration as an outcome were also assessed as being of low quality because the follow-up time was inadequate. Patient response was evaluated in three studies, which were assessed as being of medium quality with respect to this outcome. CONCLUSIONS: There is limited scientific evidence that laser treatment is as effective as a rotary bur for removing carious tissue. Treatment time is prolonged. There is limited scientific evidence that adults prefer laser treatment. No conclusions can be drawn regarding biological or technical complications, children's perception of laser treatment or the cost-effectiveness of the method.