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Developing tapered implants with the most appropriate angular characteristics requires an improved analysis of the anatomy of premolar roots.The purpose of this observational study was to analyze the 3D anatomy of premolar roots by determining the tapered slope and convergent angle (TS/CA), to transform the TS/CA patterns into those in which the tapered implants mimic natural tooth roots, and to provide TS/CA references for future investigations.A total of 73 human single-rooted premolars were surveyed and analyzed by microcomputed tomography and an associated software program. The 3D root surface area (RSA), the radius/diameter (R/D) at the planned first to tenth millimeter levels apical to the cementoenamel junction (CEJ), and the TS/CA at corresponding levels were calculated. The results were statistically analyzed by using an independent samples t test to assess the general differences of tested parameters between maxillary and mandibular premolars. A paired t test was used to examine the significant intragroup TS/CA differences between sequential coronoapical levels. One-way ANOVA was applied to study the general significance of developmental patterns in maxillary and/or mandibular groups. Two-way ANOVA was used to inspect the TS/CA significance at various measurements coronoapically between the maxillary and mandibular premolars (α=.05).Generally, the RSA, root length, R/D, and TS/CA parameters examined for the maxillary premolar roots differed significantly from those for the mandibular roots at the evaluated levels (P.05). According to the measurements, the maxillary premolar roots generally exhibited nonsignificant RSA and R/D reduction patterns, with a decreasing angle of TS=13.44 degrees and CA=24.53 degrees coronoapically. However, mandibular premolar roots exhibited a significant reduction pattern, with TS=11.25 degrees and CA=21.06 degrees coronoapically according to both individual and general evaluations.Based on the developmental patterns of the evaluated TSs/CAs, tapered implants imitating premolar root anatomy should have a conical rather than a cylindrical shape, and the R/D of these models should be reduced to half at the apical third. However, further studies are warranted to identify more TS/CA characteristics related to the tapered implants, including the TSs/CAs of other tooth types.

Background In patients with gingival exposure on smiling due to altered passive eruption, esthetic crown lengthening is often indicated. Meticulous planning and surgical precision are key for successful outcomes. Surgical guides are helpful tools that are seldomly reported on in the literature related to esthetic crown lengthening procedures. Types of Studies Reviewed The authors searched the literature for articles that described the planning, tools, and execution related to esthetic crown lengthening procedures. Results Several techniques have been reported to guide the esthetic crown lengthening procedure, ranging from direct bone level measurement to 3-dimensional printed surgical guides. Practical Implications This review serves the clinician as an aid in the decision-making process for esthetic crown lengthening procedures and available surgical guide options, including computer-based guides.

Aim and objective To evaluate the effect of cervical margin relocation (CMR) for crowns designed using CAD/CAM technology and fabricated from lithium disilicate (e.max, CAD) before and after aging; and to compare the fracture forces and failure type of the tested crowns. Materials and methods Mesio-occluso-distal(MOD) cavities 1 mm above the cementoenamel junction(CEJ) were prepared on 40 maxillary first premolars. The teeth were divided into four groups. In group A, all cervical margins (CM) were located 1 mm above the CEJ. However, in both mesial and distal proximal boxes of groups B, C, and D, in addition to the MOD cavities, the CMs were extended 2 mm on both sides below the CEJ apically to simulate the CMR technique. In group B, the mesial and distal proximal boxes were filled with flowable composite, while for group C and group D, specimens were filled with composite resin fillings. To simulate the CMR technique, the cavities were filled with composite layers of 3 mm in two increments. Using the CAD/CAM system, 40 standard crowns were prepared on premolars, then cemented using a dual-curing adhesive cement. Assessments of the marginal integrity of interfaces of the proximal boxes of the cemented crowned teeth were recorded. Statistical differences between groups were analyzed using the ANOVA and Bonferroni's posthoc test. Results The first null hypothesis was accepted since no statistically significant differences were found in marginal integrity before and after aging (p>0.05), while the second was partially rejected since different fractured force values were recorded and a significant difference was detected between group D and group B. The third hypothesis was rejected because the catastrophic fracture rate was the highest among the four groups. Conclusion The implementation of CMR before and after aging had a good effect on the marginal integrity of CM relocation. The CMR technique with resin luting cement of lithium disilicate crowns is effective and recommended for the restoration in deep proximal boxes of premolars or posterior teeth. Clinical significance CAD/CAM-generated e. max all-ceramic crowns with composite as the CMR enable the reconstruction of severely destroyed teeth irrespective of the position of the cavity margins.

Background The selection of temporary anchorage device (TAD) site can be a challenging task since one should not only consider the 2-D distances between roots, but also the entire 3-D space. Thus, the aim of this study was to evaluate the posterior maxillary region areas available for the insertion of temporary anchorage devices in reconstructed images from cone beam computed tomography (CBCT). Material and Methods Sample consisted of 72 patients with indication for orthodontic treatment, grouped into three distinct age groups: 11 to 14 years (age group 1), 15 to 19 years (age group 2) and aged 20 years or older (age group 3), which were further subdivided as to the type of malocclusion (Angle Class I, II and III). Orthopantomographic reconstructions and cross sections were obtained with the Dolphin Imaging software. The distance between the roots of maxillary teeth (canines, premolars and first molars) was determined at 5 mm of the cementoenamel junction, as well as the depth of bone availability at different insertion angles (90°, 75°, 60°, 45°). The influence of different angulations, age, and malocclusion on bone availability was evaluated by ANOVA, followed by the Bonferroni post-test. For the evaluation of the interaction of these factors, 2-way ANOVA was used. Results Bone availability was found to be poor between roots in the molar region. There was a reduction in bone availability with increasing age. With regard to angulations, greater bone availability was found in depth for 45° angulation in the canine and first premolar regions and for angulation of 75° or 90° in the molar region. However, there was no difference between bone availability in the region of the second premolars. Conclusions According to applied methodology it can be concluded that the region between canines and premolars accepts better vertical angular variations for TADs insertion. Key words:Cone-Beam Computed Tomography, Orthodontic Anchorage Procedures.

Introduction: After orthodontic treatment, some teeth undergo external root resorption due to different factors, such as the root shape, oral habits, biological and genetic factor, gender, and age. Furthermore, extraction cases, long treatment duration, and the amount of force applied during the treatment might be related to root resorption. Materials and Methods: Panoramic radiographs for 226 patients treated in the orthodontic department were screened. The lower first permanent molars, lower second premolars, and lower first premolars were measured in centimeters on a ruler using ImageJ System. Teeth were measured from the cusp tip to the cementoenamel junction (CEJ) and from the CEJ to the root apex, and then, the tooth was measured as a whole before and after the treatment. Results: Multiple analysis of variance showed that there were no interactions between the root lengths of all teeth tested and either gender, treatment type, or treatment duration (P > 0.05). Conclusion: Based on the results of this study, no statistically significance relationship between external apical root resorption and gender, type of treatment, and treatment duration was found.

Objective Various intrinsic and extrinsic stains cause discolored teeth, which is of great concern to patients, which can be treated by bleaching, enamel microabrasion, veneers, and crowns. However, bleaching leads to reduced bond strength if adhesive restorations are performed immediately.Thus, the application of antioxidant agents after bleaching has been recommended, which are proved to act as free radical scavengers, improving the bond strength. Materials and Methods A total of 120 extracted human maxillary incisor teeth were taken. Using a slow-speed diamond saw and a water coolant spray, the roots of all the teeth were removed approximately 2 mm below the cementoenamel junction. With the labial surface facing upward, each sectioned sample was embedded in the acrylic resin. Then, the central portion of the embedded tooth was ground flattened with 600-grit silicon carbide paper such that the labial enamel surface becomes smooth and evenly flat.All 120 samples were divided into two control groups (n = 20), i.e., positive control group (n = 10) and negative control group (n = 10) and five experimental groups (n = 100), such that each experimental group had 20 samples.The enamel surface in both the control groups and groups treated with antioxidants was thoroughly rinsed off with distilled water for 30 seconds and subjected to bonding procedure. Result Significant differences were observed among the experimental groups (p

The purpose of this research was to compare apical debris extrusion and fracture resistance of teeth prepared with OneCurve, WaveOne Gold, or ProTaper Universal. Materials and Methods: Mandibular premolars were prepared with OneCurve, WaveOne Gold, or ProTaper Universal. In the experimental model, debris was recovered by apical section of the root washing with distilled water. The Eppendorf tubes were weighed after 15 days of storage to establish the overall weight of the tubes, including the extruded debris. The dry weight of the ejected material was then computed. After root canal obturation, the apical root ends were trapped in the acrylic up to 2 mm below the cementoenamel junction. The fracture force was calculated and given in Newtons. A one-way ANOVA test was used to compare more than two groups, followed by a Tukey post hoc test. The significance level was set at P≤ 0.05. Results: The results revealed a statistically significant difference in extruded debris between OneCurve, WaveOne Gold, and ProTaper Universal (P

Background This study aimed to assess the interradicular distance and alveolar bone thickness of Persian adults with different sagittal skeletal patterns for miniscrew insertion using cone-beam computed tomography (CBCT). Methods This cross-sectional study was conducted on maxillary and mandibular CBCT scans of 60 patients (18–35 years) in three groups (n = 20) of class I, II and III sagittal skeletal pattern. Anatomical and skeletal parameters were measured at 2, 4 and 6 mm apical to the cementoenamel junction (CEJ) by one examiner. The intra- and inter-class correlation coefficients were calculated to assess the intra, and interobserver reliability. Data were analyzed by ANOVA and Tukey’s test (alpha = 0.05). Results The intra- and interobserver reliability were > 0.9 for all parameters. The largest inter-radicular distance in the maxilla was between the central incisors (1–1) in classes I and III, and between premolars (4–5) in class II patients. The largest inter-radicular distance in the mandible was between molar teeth (6–7) in all three classes. The buccal cortical plate thickness was maximum at the site of mandibular first and second molars (6–7). The posterior maxilla and mandible showed the maximum thickness of cancellous bone and alveolar process. Wide variations were noted in this respect between class I, II and III patients. Conclusions The area with maximum inter-radicular distance and optimal alveolar bone thickness for miniscrew insertion varies in different individuals, depending on their sagittal skeletal pattern.

Objectives To assess the changes in alveolar bone of the mandibular second molars following molar protraction and investigate the factors associated with the alveolar bone changes. Materials and Methods Cone-beam computed tomography of 29 patients (mean age 22.0 ± 4.2 years) who had missing mandibular premolars or first molars and underwent molar protraction were reviewed. Alveolar bone level was measured as the distance from the cementoenamel junction at six points, buccal, lingual, mesiobuccal (MB), mesiolingual (ML), distobuccal (DB), and distolingual (DL), of the second molars at pretreatment (T0) and after molar protraction (T1). Factors associated with alveolar bone changes at the distal and mesial of the second molars were assessed. Results Mean alveolar bone changes ranged from −1.2 mm (bone apposition) to 0.8 mm (bone resorption). The presence of a third molar impaction at T0 (P < .001), third molar angulation at T0 (P < .001), and Nolla's stage of third molar at T0 (P = .005) were significantly associated with alveolar bone level changes distal to the second molars. Treatment duration (P = .028) was significantly associated with alveolar bone level changes mesial to the second molar. Conclusions Patients with impacted third molars, third molars at an earlier stage of development, and mesially angulated third molars at pretreatment may have less alveolar bone resorption distal to the second molars following protraction. Patients with increased treatment time may have reduced alveolar bone resorption mesial to the second molars.

To evaluate the relationship between the tomographic sagittal root position (SRP) of maxillary anterior teeth and periodontal phenotype (PP). Seventy volunteers (420 teeth) were evaluated. Clinical and photographic exams included the evaluation of gingival phenotype (GP) by transparency of the periodontal probe, keratinized tissue width (KTW), gingival architecture, tooth shape, and papilla height (PH). Soft tissue tomographic scan (ST-CBCT) measurements included the SRP classification, GP, gingival thickness in the tissue zone (GT-TZ) and in the bone zone (GT-BZ), buccal bone thickness (BBT), and the distances from the gingival margin and from cementoenamel junction to the buccal bone crest (GM-BBC and CEJ-BBC). Kruskal–Wallis test and a linear regression analysis model were used. The frequency of SRP over the 420 teeth was 65.2% (class I), 9.3% (class II), 0.7% (class III), and 24.8% (class IV). Linear regression analysis showed that SRP is related to PP (p

This study analyzed the root trunk (RT) and the pre-furcation area (PFA) of mandibular first molars. Thirty lower first mandibular molars extracted due to advanced periodontal disease were evaluated in a high-energy spiral computerized micro-tomography. Two gutta-percha markings on the cementoenamel junction (CEJ) and at the furcation entrance (FE) at buccal and lingual surfaces served as reference points for measurements of RT length, and PFA width and depth, at the levels of CEJ, 1 mm apical to CEJ, 2 mm apical to CEJ, and at the FE. The mean RT length was 2.49 mm at buccal and 3.18 mm at lingual sides. The mean widths of the PFA at CEJ, at 1 and 2 mm apical to CEJ, and at FE were 2.9, 3.4, 3.9 and 4.3 mm, respectively, while the mean depths were 0.19, 0.32, 0.57 and 1.1 mm, respectively. The PFA coincided with CEJ in 10 buccal and 10 lingual surfaces, representing 33.33% of the sample. There was a negative correlation between RT length and PFA dimensions. This study concludes that the RT length was smaller than previous studies. From the CEJ up to the furcation entrance, the PFA showed a progressive increase in width and depth. The coincidence of the PFA area beginning at the CEJ in 1/3, and the negative correlation between RT length and PFA dimensions may represent greater risk factor for the early development of furcation lesions.

Purpose Identifying buccal and oral bone as an important supporting periodontal structure for teeth provides important information for treatment planning in periodontics and orthodontics. This study aims to add evidence to the knowledge of preciseness of cone beam computed tomography (CBCT) measurements of the vertical dimension of buccal and oral bone. The hypothesis is that CBCT is an accurate and reliable method to measure vertical vestibular and oral bone loss. Methods The amount of vertical buccal and oral bone loss (bl) of 260 sites of 10 human cadavers was investigated clinically and radiographically by CBCT. Radiographic measurements were rated by two blinded raters. Measurements and the corresponding differences between clinical and radiological findings are described by medians and quartiles (Q1–Q3). For statistical analysis, Lin’s concordance correlation coefficient (CCC) and Bland–Altman plots were calculated. Results The CCC between the raters was 0.994 (95% confidence interval 0.992–0.995). The median bone loss (bl) distance from the cementoenamel junction (CEJ) to the bony defect (BD) was 3.5 mm (range 3–5 mm). The median bl measured in the CBCT was 3.8 mm (range 3.1–4.8 mm). The median difference of the 2 measurements for all sites included in the study (N = 260) was −0.2 mm (−0.7 to 0.3 mm). Conclusions CBCT seems to be an accurate and highly reliable method to detect and describe vertical buccal and oral bone loss. It could improve planning and prediction for successful combined periodontal and orthodontic therapies.

Aim and objective This in vitro study evaluates and compares the changes in pulp chamber temperature during direct fabrication of provisional restorations in maxillary central incisors after using three different cooling techniques. Materials and methods Total of 60 samples of maxillary central incisors along with their putty indices were divided into four groups (one control and three experimental) and were prepared using a surveyor cum milling machine. Teeth were sectioned 2 mm below cementoenamel junction and a K-type thermocouple wire was inserted in the tooth and secured at the pulpal roof using amalgam. Putty index filled with DPI tooth molding resin material [polymethyl methacrylate (PMMA)] was placed on the tooth and temperature changes per 5 seconds were recorded by temperature indicating device for the control, on-off, precooled putty, and dentin bonding agent (DBA) group. Results The highest mean obtained was of the control (11.04°C), followed by DBA group (9.53°C), precooled putty group (6.67°C), and on-off group (1.94°C). Precooled putty index group took maximum time to reach the baseline temperature (847.5 seconds). Conclusion On-off technique is the most effective method to reduce the intrapulpal temperature during polymerization, as compared to the other techniques used in the study. Retardation in the polymerization process was seen in precooled putty group, which may make this technique clinically inadvisable. Clinical significance Thermal protection of pulp must always be considered during direct fabrication of provisional restoration when a PMMA-based resin is used. By using on-off technique, not only the thermal insult to the pulp can be effectively minimized but also the harmful effects of residual monomer (poor marginal fit and pulpal irritation) can be eliminated.

Objective The aim of this study was to compare the differences in mandibular posterior anatomic limit (MPAL) distances stratified by vertical patterns in patients with skeletal Class III malocclusion by using cone-beam computed tomography (CBCT). Methods CBCT images of 48 patients with skeletal Class III malocclusion (mean age, 22.8 ± 3.1 years) categorized according to the vertical patterns (hypodivergent, normodivergent, and hyperdivergent; n = 16 per group) were analyzed. While parallel to the posterior occlusal line, the shortest linear distances from the distal root of the mandibular second molar to the inner cortex of the mandibular body were measured at depths of 4, 6, and 8 mm from the cementoenamel junction. MPAL distances were compared between the three groups, and their correlations were analyzed. Results The mean ages, sex distribution, asymmetry, and crowding in the three groups showed no significant differences. MPAL distance was significantly longer in male (3.8 ± 2.6 mm) than in female (1.8 ± 1.2 mm) at the 8-mm root level. At all root levels, MPAL distances were significantly different in the hypodivergent and hyperdivergent groups (p < 0.001) and between the normodivergent and hyperdivergent groups (p < 0.01). MPAL distances were the shortest in the hyperdivergent group. The mandibular plane angle highly correlated with MPAL distances at all root levels (p < 0.01). Conclusions MPAL distances were the shortest in patients with hyperdivergent patterns and showed a decreasing tendency as the mandibular plane angle increased. MPAL distances were significantly shorter (~3.16 mm) at the 8-mm root level.

Gingival recession accounts for apical migration of the gingival margin, resulting in exposure of the cementoenamel junction and root surface, with exposure of the root surface linked to deteriorated esthetic appearance and increased dentinal hypersensitivity. Various surgical techniques have been used to correct labial gingival recession defects. The present study evaluated and compared the results of semilunar coronally positioned flap (SCPF) alone and in conjunction with free gingival graft (FGG) for the treatment of Miller Class I and II gingival recession defects in maxillary anterior teeth. A total of 20 bilateral Miller Class I and II gingival recession sites were included and randomly allocated (n = 10 sites/group) to either the semilunar coronally positioned flap technique alone (SCPF group; control) or with FGG (SCPF+FGG group; test). Longitudinal alterations in probing depth (PD), recession width (RW), recession height (RH), width of keratinized tissue (WKT), and clinical attachment level (CAL) were measured and analyzed for both groups at 1-, 3-, 6-, and 12-month follow-ups. Both groups saw a significant decrease in RH, RW, and CAL and a significant increase in WKT. No statistically significant difference was observed in the final root coverage outcome between both groups in terms of RH, RW, and CAL, but a significant increase in WKT was seen with SCPF+FGG. Both techniques demonstrated optimal results without significant differences in the final root coverage outcomes except for WKT, which had a statistically significant increase in the SCPF+FGG group.

Impacted mandibular third molars (M3M) are associated with the occurrence of distal caries on the adjacent mandibular second molars (DCM2M). In this study, we aimed to develop and validate five machine learning (ML) models designed to predict the occurrence of DCM2Ms due to the proximity with M3Ms and determine the relative importance of predictive variables for DCM2Ms that are important for clinical decision making. A total of 2642 mandibular second molars adjacent to M3Ms were analyzed and DCM2Ms were identified in 322 cases (12.2%). The models were trained using logistic regression, random forest, support vector machine, artificial neural network, and extreme gradient boosting ML methods and were subsequently validated using testing datasets. The performance of the ML models was significantly superior to that of single predictors. The area under the receiver operating characteristic curve of the machine learning models ranged from 0.88 to 0.89. Six features (sex, age, contact point at the cementoenamel junction, angulation of M3Ms, Winter's classification, and Pell and Gregory classification) were identified as relevant predictors. These prediction models could be used to detect patients at a high risk of developing DCM2M and ultimately contribute to caries prevention and treatment decision-making for impacted M3Ms.

Aim: to evaluate canal cleanliness after using manual dynamic activation, passive ultrasonic irrigation and photoactivated disinfection in comparison with conventional needle irrigation, using scanning electron microscopy Methods: Sixty single rooted human premolars with nearly straight single canal were collected, the crowns of all teeth were removed near the level of cementoenamel junction to obtain approximately 15 ±1 mm uniform root lengths. After instrumentaion with ProTaper Next files up to X4 (40/06), roots were randomly divided into 4 equal groups (n=15) according to the method of final irrigation activation. Group I: Conventional needle and syringe irrigation. Group II: Manual dynamic activation. Group III: passive ultrasonic irrigation. Group IV: photoactivated disinfection. Canal cleanliness was evaluated with SEM using different magnification (X350- X1000). Results: Group III had the best cleanliness of the root canal while Group I had the worst cleanliness, there were statistical significant differences between Group I versus Groups II and III and between Group III and Group IV (P ≤ 0.05). Regardless the irrigation activation method, the coronal level showed significantly less amount of smear layer and remaining debris than the apical level. Conclusions: None of the tested final irrigation activation methods resulted in completely clean canal wall.

Relevance. It is currently relevant to study and compare the effectiveness of the autologous connective tissue grafts and the combination of collagen-based and autologous platelet-rich plasma in the surgical treatment of Miller Class I gingival recessions.Materials and methods. We examined and treated 48 (20 male (41.67%) and 28 female (58.33%)) patients aged from 25 to 40 years with Miller Class I gingival recessions. All gingival recessions were treated surgically using a modified twolayer tunnel technique. The patients were divided into two groups according to the graft type. Group I (24 patients (50%) had a connective tissue graft from the hard palate. Group II (24 patients (50%) used the combination of the autologous platelet-rich plasma and 3D collagen matrix Fibromatrix for the regeneration of oral soft tissues. We removed the sutures on the 14th day. The patients were followed up on the 7th and 14th days and in 1.3 months.Results. 48 Miller Class I gingival recessions were treated between 2018 and 2020. The depth of gingival recessions averaged 3.5 ± 1.13 mm before treatment. The level of the attached keratinized gingiva regarding the cementoenamel junction significantly (p < 0.001) improved in both groups after the surgery. The width and thickness of the keratinized gingiva best increased in group II. The mean effectiveness of gingival recession treatment was 84% in study group I and 96% – in study group II. Pain syndrome, fibrinous plaque and soft tissue edema were insignificant in group II.Conclusion. The combination of the autologous platelet-rich plasma and Fibromatrix, collagen 3D matrix, for the regeneration of the oral soft tissues is a more effective technique for the treatment of Miller Class I gingival recessions. This technique has several advantages. It is minimally invasive, less painful, soft tissue postoperative swelling is less and the received volume of the attached keratinized gums is larger than with a connective tissue graft.

Background This study evaluated the effects of infrared light laser therapy (ILLT) on ligature-induced periodontitis in rats using micro-computed tomography (micro-CT), histology, fibroblast migration, and viability analysis. Methods Forty-eight rats were randomly distributed into three groups: control (no periodontitis), PDC (periodontitis without laser therapy), and PD+L (periodontitis with laser therapy). Periodontitis was induced by ligature placement for four weeks. The 12-week-old rats (baseline) were subjected to laser treatment and euthanized 30 days after. After treatment, the mandibular first molars were prepared for micro-CT scanning, and histological sections were assessed as to the cementoenamel junction, alveolar bone crest, and polymorphonuclear (PMN) cell infiltration. In vitro assays were carried out to examine NIH/3T3 fibroblast viability after laser therapy. Results Migration and cell viability assays revealed that the ILLT maintained fibroblast cell viability with 4 J/cm2 , reaching 100% healing. The control group (at baseline and 30 days) presented a statistically significant difference from the PDC group at 30 days in terms of distance from the cementoenamel junction to the alveolar bone crest (CEJ-ABC). The PD+L group showed a statistically substantial difference from the PDC group at 30 days in terms of trabecular thickness (Tb.Th), degree of anisotropy (DA), and closed porosity percentage (Po%). Conclusion Infrared light laser therapy seemed to preserve the bone structure in the in vivo periodontitis induction model at 30 days and did not reduce cell viability or increase fibroblast migration in vitro. The ILLT provides positive effects on mandibular bone microstructure. This article is protected by copyright. All rights reserved.

Objectives The aim of this study was to determine the effectiveness of using an access opening guide in teaching ideal access opening shape and preventing excessive tooth loss, with a focus on predoctoral dental students. Methods Ninety teeth that were mounted in a box just below the level of the cementoenamel junction using tray resin were randomly divided into two study groups. An access opening guide produced using a 3D printer (AOG-3DP) was designed using cone-beam computed tomography (CBCT). The AOG-3DP was applied in the test groups, while no aid was used in the control group. Access preparations in both groups performed by predoctoral dental students were scanned using CBCT to detect overpreparation. The preparation time and access cavity volume were evaluated. Results The mean times required for achieving access opening were 327.2 and 97.4 s in the control and AOG-3DP groups, respectively, for premolars, and 547.4 and 104.5 s for molars. The mean volumes for premolars and molars differed from the ideal cavities by 38.1 and 72.2 mm3 , respectively, in the control group, and by -2.0 and -8.7 mm3 the AOG-3DP group. Conclusions Using the AOG-3DP significantly reduced the access opening time for premolars and molars. However, there is a limitation in that CBCT DICOM images must be converted to stereolithographic .stl files in order to be printed via 3D technology. This requires additional preclinical treatment time for imaging and subsequent printing. It could be considered that this can be a useful method in difficult cases.

Objective To evaluate bone availability at the infrazygomatic crest for extra-alveolar bone miniscrew insertion in subjects with different vertical and sagittal skeletal patterns. Setting and sample population Measurements of the infrazygomatic crest were performed on multislice computed tomography scans from 58 adults with different skeletal patterns. Materials and methods Infrazygomatic crest bone depth was measured at 4, 5 and 6 mm from the cementoenamel junction (CEJ) of the maxillary first molar at three different angles (60°, 70° and 80°) in the first molar occlusal plane. The sagittal and vertical skeletal patterns were determined. Analysis of variance followed by Tukey's post hoc test was used (P ≤ .05). Results Bone depth was greater near the CEJ (8.7 ± 3.1 mm) and lower in the apical area (5.8 ± 2.7 mm). In Class II subjects, considering 6 mm from the CEJ, there was a significantly lower depth at the 80° angle (5.4 ± 2.5 mm) than at 60° (8.6 ± 3.5 mm; P = .007). In mesofacial subjects, considering 5 and 6 mm from the CEJ, bone depth was lower at 80° (5.7 ± 3.2 mm and 5.3 ± 2.5 mm) than at 60° considering 4 mm from the CEJ (P ≤ .019). Conclusion Bone availability was lower at the apical level, especially in Class II and mesofacial subjects. Therefore, when the planned insertion site is located in the apical direction, it is recommended to choose shorter miniscrews (2.0 x 12mm) and a smaller insertion angle (60°) and/or to plan a miniscrew bone insertion deep enough to allow bicortical fixation.

Introduction C-expanders are tissue- and bone-borne maxillary expanders that are anchored by 6 orthodontic miniscrews, 3 on each side of the palate. The purpose of the study was to investigate the effect of C-expanders on the circummaxillary sutures and bucco-palatal axis of teeth in 3-dimensional finite element analyses when anchor screw vectors are different. Methods Five expansion models were studied on the basis of the vertical positions of anchor screws on the palate. Anchor screws for models A, B, and C were placed symmetrically at 4 mm, 7 mm, and 15 mm below the cementoenamel junction (CEJ), respectively. Anchor screws for models D and E were placed asymmetrically at 4 mm and 15 mm below CEJ and 7 mm and 15 mm below CEJ, respectively. Stress, displacement, and angular changes of the bone and teeth were measured in elastoplastic behavior models using a static-nonlinear simulation in an implicit method. Results Symmetrical and asymmetrical anchor screw placement with different vertical vectors were compared using finite element analyses on 5 models. Conclusions Using different vectors of anchor screws for C-expanders does change the pattern of palatal expansion (null hypothesis was rejected). The current investigation presents a promising future of controlled asymmetric skeletal maxillary expansion when asymmetric maxillary architecture needs to be corrected for successful orthodontic outcomes without involving orthognathic surgeries.

Objectives: The aim of this study was to evaluate and compare the push-out bond strength of bioceramic sealer and resin-based sealer on Erbium-doped Yttrium Aluminum Garnet (Er:YAG) treated root canals. Material and Methods: Sixty single-rooted teeth were collected, decoronated apical to the cementoenamel junction, maintaining the minimum root length of 14 mm. Samples were instrumented with WaveOne Gold primary file and divided into two experimental groups (n = 30), based on laser irradiation: Group I: No laser and Group II: Er:YAG laser irradiated. Groups I and II were again divided into two subgroups “a” (AH Plus) and “b” (mineral trioxide aggregate [MTA] Fillapex) with 15 samples in each group. As per the grouping, sealers were coated onto the canal walls and obturated. After 24 h of storage in 100% humidity at 37°C, all the samples were sectioned transversely and push-out test was performed using universal testing machine. Stereomicroscope was used to determine the mode of failure. A one-way analysis of variance was employed to compare the mean POBS. Kolmogorov–Smirnov and Shapiro–Wilk parametric tests were done to check the normality. The Games-Howell multiple post hoc test was used for pairwise comparison of the groups at a 95% confidence level. Results: Both AH Plus and MTA Fillapex exhibited higher bond strength in the laser-treated canals. AH plus exhibited superior bond strength compared to MTA Fillapex in both laser and non-laser-treated groups (P < 0.05). AH Plus groups have predominantly presented cohesive failure whereas MTA Fillapex presented mixed failures. Conclusion: Irradiation with Er:YAG laser in the root canal before obturation improves the bond strength significantly. The adhesive properties of MTA Fillapex are comparable to that of AH Plus.

OBJECTIVE Standard methods of evaluating tooth long axes are not comparable (digital dental models [DDMs], panoramic and cephalometric radiographs) or expose patients to more radiation (cone-beam computed tomography [CBCT]). This study aimed to compare angular changes in tooth long axes using DDMs vs using CBCTs. SETTINGS AND SAMPLE POPULATION Secondary data analysis of DDMs and CBCTs, taken before and after orthodontic treatment with piezocision of 24 patients. METHODS Angular changes in tooth long axes were evaluated using landmarks on first molars (centre of the occlusal surface and centre of the furcation), canines and incisors (cusp tip and centre of the root at the cementoenamel junction). Wilcoxon test, intraclass correlation coefficient (ICC) and Bland-Altman plots were used to test intra- and inter-rater agreement and compare DDM and CBCT measurements. RESULTS The mesiodistal angulation and buccolingual inclination DDM measurements were reproducible. Overall mean differences between DDM and CBCT measurements of mesiodistal angulation, 1.9°±1.5°, and buccolingual inclination, 2.2 ± 2.2°, were not significant for all teeth. ICC between DDM and CBCT measurements ranged from good (0.85 molars) to excellent (0.94 canines; 0.96 incisors). The percentages of measurements outside the range of ±5 were 17.4% for molars, 13.8% for canines and 4.5% for incisors. CONCLUSIONS DDM assessment of changes in tooth long axes has good reproducibility and yields comparable measurements to those obtained from CBCT within a 5° range. These findings lay the groundwork for machine learning approaches that synthesize crown and root canal information towards planning tooth movement without the need for ionizing radiation scans.