Quintessence International, Pre‑Print

Objectives: The goal of the study was to determine the effects of software updates on the trueness and precision of digital impressions obtained with a variety of intraoral scanner (IOS) systems. Method and materials: Seven IOS systems were investigated. Each system was tested using two versions of software, with the second version being the latest at the time of conducting the study. Scans were performed on a custom mandibular typodont model with natural teeth that were either unrestored or restored with amalgam, composite, lithium disilicate, zirconia, and gold. Eight scans were obtained for each software version on any of the tested IOS systems. Experimental IOS scans were compared against an industry-standard master scan of the typodont obtained with an ATOS Capsule scanner proven to have a trueness of 3 µm and a precision of 2 µm. Isolation of each substrate material on the digital experimental and master scans was achieved using the Geomagic metrology software for subsequent analysis of the substrate influence on accuracy. A generalized linear mixed model was used to determine the influence of the software version on the trueness and precision of the impression scan. Results: For some IOS systems, scans made with older software versions differ in accuracy compared with those obtained with the most recent software versions. Trueness was improved for most scanners following the software update, although the Element2 IOS performance deteriorated. Software updates had lesser effects on precision and showed variable trends among different systems. Software updates also influence different substrate materials scans’ accuracy, although the results show variability among IOS systems. When comparisons were done among IOS systems updated with the latest software version, best performers for complete arch trueness were the Emerald S, Trios 3, and Primescan systems. Conclusion: Software updates have a statistically significant effect on the trueness and precision of different IOS systems. These updates can have both positive and negative effects on scan accuracy, although it appears that these variations are within the clinical acceptability levels. Schlagwörter: CAD/CAM, digital dentistry, intraoral scanner, software, software update

Objective: Some modifications of orthodontic appliances such as the rapid maxillary expansion (RME) device with a Hyrax screw or Herbst are fabricated using traditional investment casting (lost-wax casting). This is precise but very labor-intensive. New technologies enable us today to use direct selective laser sintering (SLS) to produce freeform metallic structures. These machines are very expensive and only available in specialized laboratories. The aim of this investigation was to combine fused filament fabrication (FFF) 3D printing with wax-based filaments to produce orthodontic appliances via investment casting. Method and materials: For demonstration purposes, a lingual arch, a palatal arch, and an RME appliance were digitally designed based on an intraoral scan. The *.stl files were sliced and printed with a dual-nozzle FFF printer. The object was printed with a wax-based filament especially suited for investment casting, and support structures were printed with water-soluble polyvinyl-alcohol (PVA) filament. The printed objects were cast in metal and finished. Results: All appliances were successfully cast and polished. They were provisionally placed intraorally. The fit was clinically very good and comparable to traditionally crafted appliances. The printing and handling of the parts made of these special filaments is challenging. Conclusion: With this experiment, the successful production of investment casting using FFF printing was shown for the first time. Schlagwörter: 3D printing, computer modeling, fused filament fabrication, investment casting, orthodontic appliance design

Objectives: To describe the step-by-step procedure of a novel surgical technique consisting of a combination of the laterally closed tunnel (LCT) and the modified coronally advanced tunnel (MCAT) (ie, LCT/MCAT), designed to treat multiple mandibular adjacent gingival recessions (MAGR) and to present the clinical outcomes obtained in 11 consecutively treated patients. Method and materials: Eleven systemically and periodontally healthy patients (7 females, mean ± SD 33.62 ± 14.6 years, min. 19 years max. 67 years) with a total of 40 adjacent mandibular RT1 (ie, Miller Class 1 and 2) gingival recessions with a minimum depth ≥ 3 mm, were consecutively treated with LCT/MCAT, in conjunction with an enamel matrix derivative (EMD) and subepithelial palatal connective tissue graft (SCTG). Treatment outcomes were assessed at baseline and at 12 months postoperatively. Prior to surgery and at 12 months postoperatively, recession depth (RD) and recession width (RW) were evaluated. The primary outcome variable was complete root coverage (CRC, ie 100% root coverage), the secondary outcome was mean root coverage (MRC). Results: Postoperative pain and discomfort were low and the healing was uneventful in all cases without any complications. At 12 months, statistically significant (P < .05) root coverage (RC) was obtained in all patients. CRC was obtained in five patients with a total of 21 recessions, while MRC measured 92.9% (ie, 3.75 mm). In seven patients (ie, 63.6%), RC amounted to > 93% while the minimum RC per patient measured 83.76%. Conclusion: The results of the present case series suggest that the LCT/MCAT is a valuable technique for the treatment of mandibular RT1 MAGR. Schlagwörter: laterally closed tunnel, modified coronally advanced tunnel, multiple adjacent mandibular gingival recessions, recession coverage, subepithelial palatal connective tissue graft, surgical technique

Objective: Bleaching sensitivity (BS) is the most common adverse effect of tooth bleaching treatments. This study evaluated the effect of adding 1% sodium hexametaphosphate (SHMP) on BS and the whitening effectiveness of a bleaching gel. Method and materials: Two maxillary quadrants from 26 patients were randomly assigned to the experimental and control groups in a split-mouth design. In the control group the at-home bleaching gel containing 3% hydrogen peroxide, and in the experimental quadrant the same gel with 1% SHMP, were applied in individual trays for 6 hours per night for 2 weeks. The patients’ sensitivity to cold and touch as well as spontaneous sensitivity were recorded based on a visual analog scale (VAS). Changes in shade guide units (ΔSGU) and ΔE were measured using a spectrophotometer. Data were analyzed using the Kolmogorov-Smirnov, Mann-Whitney U, Wilcoxon signed-rank test, and independent sample t test. Results: Twenty-four patients completed the study. After 2 weeks, the sensitivity to cold and touch was significantly lower in the intervention group compared to the control (P = .015 and P = .039, respectively). The spontaneous sensitivity revealed no significant alteration between these two groups and during the bleaching period in each group (P > .050). Regarding both color measurements, the bleaching effectiveness in both groups was comparable, with no noticeable difference (P > .050). Conclusion: The application of 1% SHMP was able to reduce the BS with no detrimental effect on the at-home bleaching effectiveness. Schlagwörter: bleaching sensitivity, hydrogen peroxide, sodium hexametaphosphate, tooth bleaching

Objectives: To examine whether a surgeons’ position affects the axial angulation of dental implants placed freehand. Method and materials: Implants’ axial angulation was assessed on digital panoramic radiographs. An occlusal line was plotted based on the neighboring teeth/crowns. The mesial angle between the long axis of the implant and the occlusal line was measured. In addition, post-hoc ideal implant-positioning planning was done on the panoramic digital image, and the angle of the intersection between the long axis of the actual and post-hoc ideal implant was measured. Student t test for unpaired observations and the Kolmogorov-Smirnov nonparametric tests were utilized to compare the ipsi- and contralateral sides and between clinicians. Results: Seventy-seven patients (149 implants) were eligible for the study. Implants had slight mesial inclination (mean 97.7 ± 8.7 degrees) which was similar for both the ipsi- (98.2 ± 8.4 degrees) and contralateral sides (97.2 ± 9.1 degrees), P = .491. For the post-hoc planning versus actual placement comparison, the overall median (interquartile range) of implant angular deviation was minimal (−0.25 degrees [−2.98, +3.47]). This was true for both the ipsilateral (−0.5 degrees [−2.9, +2.9]) and contralateral (−0.2 [−4.2, +5.4]) sides, P = .55. For the actual versus post-hoc planning, most observations clustered around the midline (zero to minimal deviation), while for the implant to occlusal plane angle, a tendency towards slight mesial angulation was observed. Conclusions: Dental implants placed freehand by experienced clinicians have only slight axial deviation as measured from post-hoc optimal position. Implants placed in ipsilateral and contralateral sides and by left- and right-dominant-hand clinicians had similar angulations. Schlagwörter: dental implants, freehand, handedness, implant angulation, positioning accuracy

Objectives: The aim was to investigate the efficacy of citric acid and ethylenediaminetetraacetic acid (EDTA)-based treatments on smear layer removal and blood clot formation and stabilization. Method and materials: After scaling and root planing, 126 root samples were divided into seven groups treated with: deionized water; saline; citric acid solution; Ultradent Citric Acid gel; EDTA solution; EDTA-based PrefGel; or untreated. Each group was divided into three subgroups: I for the evaluation of smear layer removal and surface wettability, II and III for the evaluation of blood clot formation and stabilization in static or dynamic rinsing conditions. Results: Conditioning agent treatments increased surface wettability with respect to untreated samples (Ultradent: 45 ± 1 degrees, P = 6.2 × 10-3; EDTA: 36 ± 5 degrees, P = 8.9 × 10-7; PrefGel: 47 ± 7 degrees, P = 3.2 × 10-2). Smear layer removal (30% to 60% with respect to untreated samples) was observed for all the conditioning agents. Clot was absent on untreated samples and samples treated with deionized water. Clot quality was significantly higher for samples treated with conditioning agents (P < .05) and similar between group II and III (P > .05). A statistically significant difference (P = .027) was observed for clot coverage of the saline group, comparing static and dynamic rinsing, confirming the positive effect of treatments on clot stabilization. Conclusions: The use of conditioning agents improves smear layer removal and clot formation and stabilization with respect to scaling and root planing procedure only, which is, however, considered an essential procedure to promote wound healing in periodontal surgery. Schlagwörter: blood clot, citric acid, EDTA, periodontal tissue regeneration, root conditioning, wettability

Objective: To determine the reliability of a newly developed software application (Shadent) in natural tooth shade selection. Method and materials: A smartphone device with the self-developed Shadent software (patent no. 201841046815, Intellectual Property of India) recorded tooth shades of the maxillary right central incisor and canine for 250 volunteers. A prospective, clinical, double-blind trial was conducted. The shade match obtained under the standardized condition from Shadent software was compared with the visual method and spectrophotometer. The digital recordings were captured by two master’s candidates, while the visual shade match was evaluated by four master’s candidates and one faculty member from the Department of Prosthodontics. Crosstab analysis assessed the relationship between the visual method of shade selection, a spectrophotometer, and the Shadent software. Cohen kappa was used to measure the agreement between the methods. Results: A kappa coefficient of 0.59 was observed between the visual assessment and the Shadent software, with an agreement percentage of 64.6%. A kappa coefficient of 0.65 was observed between the spectrophotometer and the Shadent software with an agreement of 69.28%. The software also had a better Cohen kappa agreement with the maxillary central incisor than the maxillary canine. Conclusions: Shadent’s reliability was comparable with the visual and spectrophotometric methods and offered repeatability with standardized light intensity. Schlagwörter: digital imaging, natural tooth, Shadent, shade match, software application

Objectives: To investigate the association of psychiatric disorders with (1) caries experience, (2) periodontal status, and (3) metabolic syndrome (MetS) components. Method and materials: This 7-year cross-sectional study retrospectively analyzed the medical records of 504 individuals aged 18 to 90 years who attended the student dental clinic. Collected data included: demographics, smoking habits, systolic and diastolic blood pressures, pulse, waist circumference, full-mouth plaque score (FMPS), full-mouth bleeding score (FMBS), maximal pocket probing depth (PPD), average and maximal radiographic bone loss (RBL), the sum of the number of decayed (D), missing (M), and filled (F) teeth (DMFT score), and presence of MetS components, consequences and related conditions including diabetes, hypertension, hyperlipidemia, ischemic heart disease, heart failure, s/p stroke, and cancer. Results: 68 (13.5%) had psychiatric disorders with an average age of 53.42 ± 15.71 years. Psychiatric disorders were positively associated with smoking (P = .008), smoking pack-years (P = .004), DMFT score (P = .005), and negatively associated with hypertension (P = .046). Psychiatric disorders had no statistically significant associations with all periodontal indices studied and with other components of MetS. Following multivariate analysis, psychiatric disorders retained a statistically significant positive association with smoking (odds ratio [OR] and 95% confidence interval [CI] = 2.24 [1.28 to 3.92]) and with DMFT (OR and 95% CI = 1.08 [1.02 to 1.14]), and a statistically significant negative association with hypertension (OR and 95% CI = 0.46 [0.25 to 0.84]). Conclusions: Psychiatric disorders were positively associated with smoking and caries experience but not with periodontal status and metabolic morbidity. Communication between dental and medical professionals is needed to address the higher smoking consumption and caries morbidity in psychiatric patients. Schlagwörter: psychiatric disorders, dental caries, plaque score, risk factor, smoking, metabolic syndrome, diabetes, hypertension, hyperlipidemia

Objectives: To verify the effect of adjunctive enamel matrix derivative (EMD) in subgingival reinstrumentation during supportive periodontal therapy. Method and materials: Using a split-mouth design, residual periodontal pockets with probing depth (PD) of 5 to 8 mm in 13 patients were treated by subgingival reinstrumentation with (test teeth) and without (control teeth) EMD. At baseline and after 6 and 12 months the clinical variables PD, clinical attachment level (CAL), and bleeding on probing (BOP) were recorded. At the same appointments gingival crevicular fluid (GCF) was collected to analyze for interleukin (IL)-1β, matrix metalloproteinase (MMP)-8, IL-10, and transforming growth factor (TGF)-β. Results: Statistically significant improvements in PD, CAL, and BOP occurred in both groups. The reduction of PD was significantly higher in the test group than in the control group after 12 months (P = .005). The change of IL-1β within 12 months was significantly different between both groups (P = .019). No other significant differences were detected between both groups. Conclusion: The study suggests that subgingival reinstrumentation with adjunctive EMD could additionally reduce probing pocket depth and the need for periodontal surgery. Schlagwörter: biomarkers, clinical variables, enamel matrix proteins, periodontitis, scaling and root planing

Objectives: This 6-month randomized controlled study aimed at evaluating the clinical outcomes of multiple irrigations of 10% povidone-iodine (PVP-I) as an adjunct to full-mouth scaling and root planing (SRP) in the treatment of chronic periodontitis. Method and materials: Seventeen patients were included. A split-mouth design randomly assigned one side as the test side (SRP + PVP-I) and the other side as the control side (SRP + NaCl). After full-mouth SRP, the control side received subgingival irrigation with 10 mL 0.9% NaCl solution. The test side received 10 mL of PVP-I 10%. Plaque Index (PI), bleeding on probing (BOP), probing pocket depth (PPD), and clinical attachment level (CAL) parameters were assessed at baseline and after 3 and 6 months. During recall visits (3 and 6 months), residual deep periodontal pockets of ≥ 6 mm were cleaned with the same protocol and randomization. Results: PI, BOP, PPD, and CAL were improved in both sides after 6 months. No significant differences were seen between control and test sides for the all clinical parameters after 6 months. Conclusion: Multiple subgingival irrigations of 10% PVP-I or 0/9% NaCl combined to one-stage full mouth SRP in patients with chronic periodontitis showed a reduction of all clinical parameters until 6 months. There is a trend in favor of the povidone group for PPD. Schlagwörter: antiseptics, chronic periodontitis, nonsurgical treatment, periodontal treatment, povidone-iodine, root planning

Objective: This study examined the impact of early biofilm on the tooth surface, during the assessment of initial enamel erosion using swept-source optical coherence tomography (SS-OCT). Method and materials: Forty-five enamel windows of 2 × 4 mm2 were prepared on 23 extracted human teeth. The specimens were exposed to citric acid (pH 3.2) for 30 minutes and randomly divided into three groups (n = 15): Group 1, no biofilm; Group 2, 1-day-old biofilm; and Group 3, 3-day-old biofilm. Specimens in Groups 2 and 3 were inoculated with oral bacteria (Streptococcus sanguinis, Streptococcus mitis, and Actinomyces naeslundii) to produce early laboratory-cultivated biofilms for 1 and 3 days respectively. Surface microhardness (SMH) measurements were taken at pre- (t1) and post-erosion (t2); and SS-OCT scans were done at t1, t2, and post-biofilm cultivation (t3). Integrated reflectivity (IR) of the tooth-air interface (IRsurface) and enamel (IRenamel) were computed from the mean A-scans. Statistical analysis was performed using paired t tests and one-way ANOVA (α = .05). Results: A significant increase in IRenamel was observed at t2 (P < .05). At t3, IRsurface between Group 1 (control) and Group 2 (P = .012) as well as Group 3 (P = .001) were significantly different. Significant variances in IRenamel were perceived between t2 and t3 for Groups 2 and 3 but not for Group 1. Conclusion: As early biofilm affected SS-OCT assessment of initial enamel erosion, they should be removed from the tooth surface prior to OCT procedures. Schlagwörter: assessment, biofilm, detection, enamel erosion, initial erosion, optical coherence tomography