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.

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.

Cost-effectiveness of caries excavations in different risk groups - a micro-simulation study.

BACKGROUND: Whilst being the most prevalent disease worldwide, dental caries is increasingly concentrated in high-risk populations. New caries treatments should therefore be evaluated not only in terms of their cost-effectiveness in individuals, but also their effects on the distribution of costs and benefits across different populations. To treat deep caries, there are currently three strategies: selective (one-step incomplete), stepwise (two-step incomplete) and complete excavation. Building on prior research that found selective excavation generally cost-effective, we compared the costs-effectiveness of different excavations in low- and high-risk patients, hypothesizing that selective excavation had greater cost-effectiveness-advantages in patients with high compared with low risk. METHODS: An average tooth-level Markov-model was constructed following the posterior teeth in an initially 18-year old male individual, either with low or high risk, over his lifetime. Risk was assumed to be predicted by several parameters (oral hygiene, social position, dental service utilization), with evidence-based transition probabilities or hazard functions being adjusted for different risk status where applicable. Total lifetime treatment costs were estimated for German healthcare, with both mixed public-private and only private out-of-pocket costs being calculated. For cost-effectiveness-analysis, micro-simulations were performed and joint parameter uncertainty introduced by random sampling of probabilities. Cohort analyses were used for assessing the underlying reasons for potential differences between strategies and populations. RESULTS: Selective excavation was more effective and less costly than both alternatives regardless of an individual's risk. All three strategies were less effective and more costly in patients with high compared with low risk, whilst the differences between risk groups were smallest for selective excavation. Thus, the cost-effectiveness-advantages of selective excavation were more pronounced in high-risk groups, who also benefitted the most from reduced private out-of-pocket treatment costs. CONCLUSIONS: Whilst caries excavation does not tackle the underlying sources for both the development of caries lesions and the potential differences of individuals' risk status, selective excavation seems most suitable to treat deep lesions, especially in patients with high risk, who over-proportionally benefit from the resulting health-gains and cost-savings.

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.

[Cost-minimization analysis of two methods during the prevention of dental fear during caries filling treatments].

OBJECTIVE: To determine the economic effects on the prevention of dental fear (DF) by pre-operation-education or local anesthesia method during the process of tooth filling. METHODS: One hundred and fifty school children of age 7 to 12, participating in this study, suffered from occlusal caries on their mandibular first molars. They were divided into 3 groups, with 25 boys and 25 girls each. Group A (pre-operation-education) was showed video tape on caries to, familiarized with clinic environment, including dental chairs and instruments; Group B (local anesthesia) received injection of 1.8 ml of 2% lidocaine for local anesthesia about 15 minutes before treatment; Group C (blank) received no intervention for DF. Thereafter, all subjects received same filling treatment. During that process, each DF case was evaluated blindly based on Venham's clinical ratings of anxiety and cooperation. Cost-minimization analysis was then studied. RESULTS: Significant difference was found between groups, but not between group A and B in DF rate (5/50, 9/50 and 21/50, chi(2) = 15.503 1, P = 0.000 4). The costs of each case in 3 groups were 83.99 Yuan, 87.09 Yuan and 87.76 Yuan respectively. CONCLUSION: Between pre-operation-education and local anesthesia methods, the former was worth promoted for it's better clinical effect in DF prevention with lower cost.

Long-term survival and cost-effectiveness of five dental restorative materials used in various classes of cavity preparations.

This retrospective study examined the survival and cost-effectiveness of five different types of dental materials used to restore various classes of cavity preparations in permanent teeth. Information on the restorations was obtained from the casenote records of 100 long-term adult patients treated at various times by 20 dentists in three city practices. Patients attended for checkups and restorative treatments on a regular basis for around 25 years on average, ranging from 10 to 46 years. All of the restorative materials lasted well, despite the frequent patient checkups and changes of dentists. Cusp-covered amalgams were approximately 3.8 times more cost-effective than were either cast gold or ceramometal crowns, and resin composites were approximately 3.7 times more cost-effective than were cast gold inlays for restoring Class IV preparations. However, there were no significant differences found in the cost-effectiveness of using either resin composites or glass-ionomer cements to restore Class III preparations, or between using either of these two materials, or amalgams, to restore Class V preparations.

Cost benefit analysis of direct posterior restorations.

A clinical study was conducted in which three operators made 232 Class I and Class II composite and amalgam restorations in a group of 49 adult patients. The time for different parts of the operative process was measured. The time periods were analysed as to the influence of the factors operator, tooth type and number of surfaces, by an analysis of variance (ANOVA). Results show that the various factors have a significant influence on the total treatment time. The treatment time for amalgam restorations is equal to the treatment time of composite restorations. The productivity of making restorations from the 'best' available amalgams, i.e. the amalgam with an extrapolated half-life time of more than 20 yr, turns out to be more than 3-4 times better than that of the 'worst' amalgams (half-life time 4 1/2-8 yr) and more than two times better than that of making restorations of the best composite material, used in this study (extrapolated half-life time of Estic MF is 10 yr).