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Although desktop stereolithography (SLA) 3D printers and photopolymerizing resin have been used increasingly in dentistry to manufacture surgical templates, studies investigating their clinical application are lacking.The purpose of this in vitro study was to evaluate the effects of build angle on the accuracy, printing time, and material consumption of additively manufactured surgical templates made with a desktop SLA 3D printer and photopolymerizing resin material.Fifty surgical templates were fabricated from 1 master digital design file using a desktop SLA 3D printer and photopolymerizing resin material at 5 different build angles (0, 30, 45, 60, and 90 degrees) (n=10). All surgical templates were digitized and superimposed with the master design file using best-fit alignment in the surface matching software program. Dimensional differences between the sample files and the original master design files were compared, and the mean deviations were measured in the root mean square (measured in mm, representing accuracy). The printing time and resin consumption for each specimen were recorded based on the information in the 3D printing preparation software program. ANOVA and the Fisher least significant difference (LSD) test were used to estimate the effects of build angles on the root mean square, printing time, and resin consumption (α=.05 for all tests).The groups 0 degree (0.048 ±0.007 mm) and 45 degrees (0.053 ±0.012 mm) had statistically significant lower root mean square values when compared with those of groups 30 degrees (0.067 ±0.009 mm), 60 degrees (0.079 ±0.016 mm), and 90 degrees (0.097 ±0.017 mm) (P.001 for all comparisons, except P=.003 for groups 30 degrees versus 45 degrees). The group 90 degrees had statistically significant higher root mean square values than all other groups (P.001 for all comparisons, except P=.010 when compared with the group 60 degrees). For the printing time, the group 0 degree required significantly less printing time than all other groups (hour:minute, 1:26 ±0:03, P.001 for all comparisons). The group 90 degrees required significantly more printing time than all other groups (2:52 ±0:06, P.001 for all comparisons). For resin consumption, the groups 0 degree (11.58 ±0.21 mL), 30 degrees (11.32 ±0.16 mL), and 45 degrees (11.23 ±0.16 mL) consumed similar amounts of resin. However, there was statistical significance between groups 0 degree and 45 degrees (P=.016). The group 90 degrees consumed the significantly least amount of resin (9.86 ±0.40 mL, P.001 for all comparisons).With a desktop SLA 3D printer, the 0-degree and 45-degree build angles produced the most accurate surgical template, and the 90-degree build angle produced the least accurate surgical template. The 0-degree build angle required the shortest printing time but consumed the most resin in the printing process. The 90-degree build angle required the longest printing time but consumed the least amount of resin in the printing process.

This technical report describes a digital process to design and fabricate a verification device directly from an intraoral scan for nonsegmental implant-supported dental prostheses. By using an open source computer-aided design software program, this technique provides an economical option for dentists and dental laboratory technicians to fabricate a computer-aided design and computer-aided manufacturing (CAD-CAM) verification device. This technique is particularly beneficial for a long scanning span and large edentulous space with multiple scan bodies, and a verification device can be used to confirm the accuracy of a CAD-CAM implant definitive cast.

Statement of problem Candida albicans has been implicated in denture stomatitis, and this effect is exacerbated by nicotine exposure. However, studies have also suggested that caffeine exposure inhibits the growth of C. albicans. The interaction effects of nicotine and caffeine are not yet clear on the growth of C. albicans. Purpose The purpose of this in vitro study was to determine the effect of caffeine on metabolic activity and biofilm formation of C. albicans growing on acrylic denture resin while simultaneously exposed to nicotine and, if an effect were to be identified, whether this effect would vary depending on the caffeine concentration. Material and methods A total of 240 acrylic resin specimens were divided into 2 equal groups (120 each). Specimens in one group were processed to measure C. albicans metabolic activity, and those in the other group were processed to measure C. albicans biofilm attachment. Ten subgroups (n=12) were established within each group with different concentration combinations of nicotine and caffeine to test the interaction effect. The first subgroup was designed as a negative control, containing 0 mg/mL of nicotine and caffeine. The following subgroups all contained 8.00 mg/mL of nicotine, and the caffeine concentrations were prepared at the following 9 levels: 0, 0.25, 0.50, 1.00, 2.00, 4.00, 8.00, 16.00, and 32.00 mg/mL. Metabolic activity was measured by using a 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-carboxanilide (XTT) assay. Biofilm attachment was measured by using spiral plating and calculated in terms of the number of colony-forming units (CFUs)/mL. Descriptive statistics and a 2-way ANOVA were conducted to determine whether the concentrations of nicotine and caffeine used affected the biofilm attachment and metabolic activity of C. albicans (α=.05). Results The presence of 8 mg/mL of nicotine increased the metabolic activity and biofilm formation of C. albicans. When compared with the 0 mg/mL of caffeine and 8.00 mg/mL of nicotine group, caffeine from 1.00 to 4.00 mg/mL significantly increased C. albicans biofilm metabolic activity. Caffeine at 16.00 and 32.00 mg/mL significantly decreased C. albicans biofilm metabolic activity in the presence of 8 mg/mL of nicotine. Caffeine from 1.00 to 32.00 mg/mL significantly decreased the biofilm formation of C. albicans in the presence of 8 mg/mL of nicotine. Conclusions The presence of 8 mg/mL of nicotine alone increased the metabolic activity and biofilm formation of C. albicans. In the presence of 8 mg/mL of nicotine with different caffeine concentrations, the results suggest that, overall, caffeine at higher concentrations (16 and 32 mg/mL) inhibited the metabolic activity and biofilm formation of C. albicans on acrylic denture resin most.

This technical report describes a novel workflow for complete denture fabrication designed to abbreviate the necessary steps for dental prostheses delivery by using a 3-appointment protocol in which preliminary impressions are made in the first session together with the registration of maxillary lip support, occlusal plane, and reference lines for tooth arrangement. A trial denture is fabricated with conventional or computer-aided design and computer-aided manufacturing procedures and is evaluated in the second appointment for esthetics, the definitive impression, and the maxillomandibular relationship record to provide precise references for definitive denture fabrication.

Statement of problem Three-dimensional radiographic assessment of buccal bone thickness and its integrity from cone beam computed tomography (CBCT) plays an essential role in immediate implant placement. However, the accuracy of CBCT measurements for the assessment of buccal bone thickness adjacent to maxillary anterior teeth is not well understood. Purpose The purpose of this observational study was to evaluate the accuracy of measuring the buccal bone thickness of maxillary anterior teeth from CBCT compared with direct measurement from histologic sections. A secondary objective was to analyze whether a minimal level of buccal bone thickness of maxillary anterior teeth can be detected from the CBCT scan. Material and methods Five embalmed human cadavers with a complete anterior dentition were included in this study, providing 30 teeth for evaluation. After preparing reference notches at the gingival margin of each tooth, the anterior segments were scanned. The buccal bone thickness at 3, 5, and 7 mm from the notches was measured on the cross-sections obtained from the CBCT and histomorphometric images for a total of 90 sites. The CBCT measurements were compared with the histomorphometric measurements, and their agreement was assessed by using the Bland-Altman plots and intraclass correlation coefficients. The sensitivity and specificity of buccal bone detection were calculated from the CBCT scan. Results Histologic examination showed absence of the buccal bone in 29 sites (32%). The mean ±standard deviation thickness of the buccal bone was 0.52 ±0.05 mm (range: 0 to 1.97 mm) from the CBCT analysis and 0.40 ±0.05 mm (range: 0 to 1.67 mm) from histology. Measurements obtained from the CBCT sections significantly overestimated the buccal bone thickness when compared with the histologic evaluation (P=.001). The intraclass correlation coefficient of buccal bone thickness between the CBCT and histology was ≤0.53, an agreement considered as poor. The sensitivity of the CBCT as a diagnostic tool to detect the presence or absence of the buccal bone was 75.4%, and the specificity was 65.5%. Conclusions The buccal bone thickness of maxillary anterior teeth was less than 2 mm at all sites as measured with both CBCT and histology evaluations. CBCT measurements had relatively low accuracy and reliability for the measurement of buccal bone thickness. These findings should be considered when using CBCT as a measuring tool for thin bone structures.

The increased precision and design of surgical templates for static computer-aided implant surgery has led to concerns of excessive heat generation from the friction between the twist drills, metal sleeves in the surgical template, and guide handles during osteotomy preparation. In addition, the presence of a surgical template can prevent proper cooling of the twist drill as it enters the osteotomy site, leading to greater heat generation. This excessive heat may result in bone necrosis and failure of osseointegration to the implant surface. This article describes a straightforward technique of incorporating an existing design feature in many virtual implant planning software programs to add an irrigation channel to the implant surgical template for effective cooling during osteotomy preparation.