Comparison of treatment effects between clear aligners and fixed appliances in patients treated with miniscrew-assisted molar distalization.

OBJECTIVES: The biomechanics in achieving molar distalization may differ between fixed appliances and clear aligners in the control of tooth movement. The objective of this study was to compare the treatment effects between clear aligners (CA) and fixed appliances (FA) in patients treated with miniscrew-assisted molar distalization. METHODS: The sample consisted of 46 subjects with mild-to-moderate crowding. A total of 22 patients treated with clear aligners (age, 25.66 ±â€…6.11 years old) and 24 patients treated with fixed appliances (age, 24.04 ±â€…4.95 years old) for miniscrew-assisted molar distalization were included in this study. The dental and skeletal changes were evaluated by the pre- and post-treatment lateral cephalograms. RESULTS: Significant changes were found with the vertical variables SN-OP angle (2.24 ±â€…3.22°, P < .05) and SN-MP angle (0.73 ±â€…1.15°, P < .05) for the FA group when compared with the CA group (SN-OP angle 0.41 ±â€…2.26° and SN-MP angle -0.21 ±â€…1.38°, P > .05). Both treatment groups achieved a 2-3 mm. molar distalization with significant intrusion of the upper molars. The CA group showed significantly less distal tipping of molars (U6^PP angle -2.29 ±â€…3.29° and L6^MP angle -2.92 ±â€…2.49°, P < .05) compared to the FA group (-5.24 ±â€…4.28° and -5.53 ±â€…5.03°, P < .05). In addition, significant retraction and lingual inclination of the upper and lower incisors were found in both groups. LIMITATIONS: The changes of tooth position were evaluated by 2D lateral cephalograms, not 3D measurements. CONCLUSIONS: Compared to fixed appliances, clear aligners seemed to have better control of vertical dimension and distal tipping of molars in patients treated with miniscrew-assisted molar distalization.

Analysis of prefabricated myofunctional appliances with different overjet and bumper designs: a three-dimensional finite element analysis.

BACKGROUND: Prefabricated myofunctional appliance can guide tooth eruption, improve dentition alignment, correct myofunctional disorders and harmful oral habits. However, its application to skeletal discrepancy may result in unsatisfactory tooth inclination. This study aimed to construct a novel appliance with overjet design to avoid this side effect and investigated its shape and mechanical changes under occlusion using three-dimensional finite element method. METHODS: We established three samples of prefabricated myofunctional appliances. The first one was edge to edge without overjet, and the outer shield of both jaws were flattened. The second one was 3 mm overjet with stepped the outer shield. The last one was 3 mm overjet, and the outer shield of both jaws were flatted, which meant the front wall of lower jaw was strengthened with bumper, termed as lower bumper. A complete dentition model was applied to the study. 150 N occlusal force was applied to each type of appliance and the deformation displacement and the changes in stress was recorded. RESULTS: The deformation was significant in the incisors regions, especially in the vertical and lateral dimensions. The maximum displacements of 3 mm overjet with step shield group were 7.08 mm (vertical), 3.99 mm (lateral), and 2.90 mm (sagittal), while it decreased to 3.92 mm(vertical), 1.94 mm (lateral), and 1.55 mm (sagittal) in overjet with bumper group. Moreover, the upper molar regions exhibited higher vertical and sagittal displacement in 3 mm overjet with step shield group, which were 3.03 mm (vertical) and 1.99 mm (sagittal), and the bumper design could decrease the maximum displacement to 1.72 mm (vertical) and 0.72 mm (sagittal). In addition, the Von Mises stress of appliances was analyzed, and results indicated that 3 mm overjet with step shield generated higher stress than other groups, with the maximum Von Mises stress was 0.9387 MP, which were 0.5858 and 0.5657 MP in edge to edge group and 3 mm overjet with lower bumper group, respectively. CONCLUSION: The prefabricated myofunctional appliances may cause deformation during occlusion. Compared to step shield group, the application of lower bumper exhibited better resistance to occlusal force.

Laboratory study of fracture resistance and failure mode of porcelain laminate veneers with different preparation depths in endodontically treated teeth.

PURPOSE: To compare the fracture resistance and failure mode of porcelain laminate veneers with different preparation depths in endodontically treated teeth. METHODS: Root canal treatment was performed for 40 maxillary central incisors, and then the teeth were divided into four groups (n= 10). The preparation depths were as follows: Group A: 0.9 mm, Group B: 0.6 mm, Group C: 0.3 mm, and in all three groups, 2 mm butt joint incisal reductions were performed; Group D was a control group with no preparation. Then 30 lithium disilicate porcelain veneers were milled by CAD- CAM method and cemented. After that, all specimens were subjected to cyclic loading and thermal cycling and finally were tested by a universal testing machine until failure occurred. RESULTS: The mean failure loads (N) after exposure to continuous load were as follows: Group A: 625.70 (401.45-1037.77), Group B: 780.32 (222.93-1391.82), Group C: 748.81 (239.68-1241.87) and Group D (control) : 509.88 (84.42-1025.85) and P= 0.216. Analysis of failure mode in four groups showed that P= 0.469. There was no significant difference between the control and the other groups. In this study, 0.3, 0.6 and 0.9 mm depths of preparation for porcelain laminate veneers for endodontically treated teeth had no significant difference in fracture resistance and failure mode with non-prepared teeth. CLINICAL SIGNIFICANCE: Reasonable consideration might be given to porcelain laminate veneer treatment for teeth that have become discolored and resistant to bleaching (such as instances where discoloration is severe following root canal treatment). This approach is considered to be on the conservative side, and has demonstrated that a labial preparation depth reduction of up to 0.9 mm does not have any impact on the failure mode or fracture resistance of endodontically-treated teeth.

Patient-reported outcomes during accelerating the en-masse retraction of the upper anterior teeth using low-intensity electrical stimulation: a randomized controlled trial.

BACKGROUND: Low-intensity electrical stimulation (LIES) is considered a relatively recent technology that has received little attention in orthodontics as a method of acceleration. This study aimed to evaluate patient-reported outcome measures when LIES is used to accelerate the en-masse retraction of the upper anterior teeth. MATERIALS AND METHODS: The sample consisted of 40 patients (8 males, 32 females; mean age 21.1 ± 2.3 years), with Class II division I malocclusion who required extraction of the first premolars to retract upper anterior teeth. They were randomly assigned to the LIES group (n = 20) and the conventional en-masse retraction group (CER; n = 20). Patient responses regarding pain, discomfort, burning sensation, swelling, chewing difficulty, speech difficulty, and painkillers' consumption were recorded at these nine assessment times: 24 h (T1), 3 days (T2), and 7 days (T3) after force application, then in the second month after 24 h (T4), 3 days (T5), and 7 days (T6) of force re-activation, and finally after 24 h (T7), 3 days (T8), and 7 days (T9) of force re-activation in the third month. RESULTS: The mean values of pain perception were smaller in the LIES group than those in the CER group at all assessment times with no statistically significant differences between the two groups except during the second and third months (T5, T6, T8, and T9; P < 0.005). However, discomfort mean values were greater in the LIES group with significant differences compared to CER group during the first week of the follow-up only (T1, T2, and T3; P < 0.005). Burning sensation levels were very mild in the LIES group, with significant differences between the two groups at T1 and T2 only (P < 0.001). Speech difficulty was significantly greater in the LIES group compared to CER group at all studied times (P < 0.001). High levels of satisfaction and acceptance were reported in both groups, without any significant difference. CONCLUSION: Both the LIES-based acceleration of en-masse retraction of upper anterior teeth and the conventional retraction were accompanied by mild to moderate pain, discomfort, and chewing difficulty on the first day of retraction. These sensations gradually decreased and almost disappeared over a week after force application or re-activation. TRIAL REGISTRATION: ClinicalTrials.gov, ClinicalTrials.gov, NCT05920525. Registered 17 June 2023 - retrospectively registered, http://clinicaltrials.gov/study/NCT05920525?term=NCT05920525&rank=1 .

Immediate implant placement in a dialysis patient. A case report.

Implant-supported rehabilitation in high-risk patients poses significant challenges for the dental team. The presence of comorbidities and increased infection risk can, for example, lead to a higher risk of implant loss. For the therapy to be completed with as few complications as possible, special anamnesis, detailed diagnostics, and a risk analysis based on those findings are indispensable. The aim of all considerations is to keep the risk of infection for the patient with a disease history to a minimum and to strive for an appropriate functional and esthetic therapeutic success. Particularly in the esthetic zone, in addition to the general health risks of the surgical procedure, esthetic aspects are increasingly taken into account in planning. The present article describes the implant-prosthetic replacement of a single anterior tooth in a dialysis patient. Several aspects (regular dialysis, missing buccal lamella, high smile line, functional risk) increased the risk of complications in this case.

Advanced digital planning approach using a 3D-printed mock-up. A case report.

OBJECTIVE: A diagnostic mock-up is a key tool that allows a preview of the outcome of an esthetic restoration. With recent developments in CAD/CAM technology, it is important to understand the pros and cons of chairside digital dentistry and the restorative materials used. The aim of the present case report is to describe in detail the use of a 3D-printed mock-up fabricated from a polymer-based material for an esthetic treatment plan within a fully digital workflow. CASE REPORT: A 45-year-old female patient presented at the clinic concerned about her esthetic appearance and the color of her anterior incisors. After a conclusive diagnosis, a restoration was planned using ceramic veneers from maxillary premolar to premolar. For a preview visualization of the outcome, an intraoral scanner was used to obtain 3D images and to allow the design of a digital smile. The template STL file was exported to a 3D printer and a 0.6-mm mock-up in A3-shade 3D resin was produced after 25 min. The mock-up was tested through a try-in and approved by the patient. As a result, the printed mock-up was considered predictable and reliable for the final restoration. CONCLUSIONS: The ease, speed, and reduced costs derived from the digital workflow, in conjunction with the accuracy of the mock-up, made the procedure highly efficient and recommendable.

Fracture resistance and failure mode of three esthetic CAD-CAM post and core restorations.

BACKGROUND: The rising demand for improved aesthetics has driven the utilization of recently introduced aesthetic materials for creating custom post and core restorations. However, information regarding the fracture resistance of these materials remains unclear, which limits their practical use as custom post and core restorations in clinical applications. AIM OF THE STUDY: This study aimed to evaluate the fracture resistance of three non-metallic esthetic post and core restorations and their modes of failure. MATERIALS AND METHODS: Thirty-nine single-rooted human maxillary central incisors were endodontically treated. A standardized post space preparation of 9mm length was performed to all teeth to receive custom-made post and core restorations. The prepared teeth were randomly allocated to receive a post and core restoration made of one of the following materials (n=13): glass fiber-reinforced composite (FRC), polyetheretherketone (PEEK) and polymer-infiltrated ceramic-network (PICN). An intraoral scanner was used to scan all teeth including the post spaces. Computer-aided design and computer-aided manufacturing (CAD-CAM) was used to fabricate post and core restorations. Post and core restorations were cemented using self-adhesive resin cement. All specimens were subjected to fracture resistance testing using a universal testing machine. Failure mode analysis was assessed using a stereomicroscope and SEM. The data was statistically analyzed using One-Way ANOVA test followed by multiple pairwise comparisons using Bonferroni adjusted significance level. RESULTS: Custom PEEK post and core restorations displayed the least fracture load values at 286.16 ± 67.09 N. In contrast, FRC exhibited the highest average fracture load at 452.60 ± 105.90 N, closely followed by PICN at 426.76 ± 77.99 N. In terms of failure modes, 46.2% of specimens with PICN were deemed non-restorable, while for PEEK and FRC, these percentages were 58.8% and 61.5%, respectively. CONCLUSIONS: Within the limitation of this study, both FRC and PICN demonstrated good performance regarding fracture resistance, surpassing that of PEEK.

Microhardness Measurements on Tooth and Alveolar Bone in Rodent Oral Disease Models.

The mechanical property, microhardness, is evaluated in dental enamel, dentin, and bone in oral disease models, including dental fluorosis and periodontitis. Micro-CT (µCT) provides 3D imaging information (volume and mineral density) and scanning electron microscopy (SEM) produces microstructure images (enamel prism and bone lacuna-canalicular). Complementarily to structural analysis by µCT and SEM, microhardness is one of the informative parameters to evaluate how structural changes alter mechanical properties. Despite being a useful parameter, studies on microhardness of alveolar bone in oral diseases are limited. To date, divergent microhardness measurement methods have been reported. Since microhardness values vary depending on the sample preparation (polishing and flat surface) and indentation sites, diverse protocols can cause discrepancies among studies. Standardization of the microhardness protocol is essential for consistent and accurate evaluation in oral disease models. In the present study, we demonstrate a standardized protocol for microhardness analysis in tooth and alveolar bone. Specimens used are as follows: for the dental fluorosis model, incisors were collected from mice treated with/without fluoride-containing water for 6 weeks; for ligature-induced periodontal bone resorption (L-PBR) model, alveolar bones with periodontal bone resorption were collected from mice ligated on the maxillary 2nd molar. At 2 weeks after the ligation, the maxilla was collected. Vickers hardness was analyzed in these specimens according to the standardized protocol. The protocol provides detailed materials and methods for resin embedding, serial polishing, and indentation sites for incisors and alveolar. To the best of our knowledge, this is the first standardized microhardness protocol to evaluate the mechanical properties of tooth and alveolar bone in rodent oral disease models.

Volumetric Analysis of Peri-implant Tissue Change Over Time: Validating an Innovative 3D Method.

PURPOSE: To validate an innovative 3D volumetric method of evaluating tissue changes proposed by Lee et al in 2020 by comparing the results of this method-in which the scanned peri-implant surfaces were transformed, visualized, and analyzed as 3D objects-to the results reported by an existing method based on calculation of the mean distance between measured surfaces. The null hypothesis was that there was no statistically significant difference between the two methods. Additionally, the present study evaluated peri-implant tissue changes 5 years after single implant placement in the esthetic zone. MATERIALS AND METHODS: Both methods were applied to 11 oral implant site casts (6 maxillary central incisor sites, 5 maxillary lateral incisor sites) taken from 11 patients at crown placement and at follow-up examinations 5 years later. The methods are based on digital workflows in which the reference and 5-year casts are scanned and the resulting STL files are superimposed and analyzed for three regions of interest (mesial papilla, central area, and distal papilla). The volumetric changes reported by the Lee et al method and the mean distance method were calculated and compared using the Spearman rank correlation coefficient (P < .01) and the Wilcoxon signed-rank test (P < .05). RESULTS: The correlation between the two sets of measurements was very high (Spearman rank correlation coefficient = 0.885). The new volumetric method indicated a mean volume loss of 2.82 mm3 (SD: 5.06), while the method based on the measurement of mean distance showed a mean volume loss of 2.92 mm3 (SD: 4.43; Wilcoxon signed-rank test result: P = .77). No statistically significant difference was found. The two methods gave equivalent results, and the null hypothesis was accepted. CONCLUSIONS: The new volumetric method was validated and can be considered a trustworthy tool.

Determining the widths of the maxillary anterior teeth for esthetics: comparison of the Mondelli and Albers formulas, esthetic proportion, and golden ratio.

The purpose of this study was to compare various formulas for idealized proportions of the maxillary incisors to the actual dimensions of natural teeth. The Mondelli formula 1 (MF1), Mondelli formula 2 (MF2), Albers formula (AF), esthetic proportion (EP) for width and height of anterior teeth, and golden ratio (GR) were calculated for a total of 50 dental students (30 women and 20 men) who participated in the study. The following measurements were obtained directly in the participant's mouth with a digital caliper: the mesiodistal and incisogingival dimensions of the maxillary central incisors, lateral incisors, and canines; the intercanine distance; and the smile width. The participants were photographed, and the smile width was also measured on the photographs. The MF1 and MF2 were each calculated twice, using both direct measurements and photographic measurements. The projected central incisor widths calculated using the MF1, MF2, and AF were compared among themselves and against the actual measurements using analysis of variance and Fisher test for multiple comparisons (α = 0.05). The EP and GR were analyzed using descriptive statistics. There was a statistically significant difference between all of the widths projected by the formulas and the actual widths of the central incisors (P < 0.05). Whether calculated from a direct or a photographic measurement, the incisor widths projected by the MF1 and MF2 were statistically similar to each other (P > 0.05). The EP values were similar to those reported in the literature. Only 2% of the participants had an incisor width ratio (central incisor/lateral incisor) that matched the GR of 1.618, while 86% fell within the range of 1.2 to 1.4. Overall, the proportions calculated with the MF1, MF2, AF, EP, and GR did not exactly match the actual dimensions of natural teeth. The formulas and the proportions available in the literature can assist in esthetic planning, but the individual characteristics of each patient and expertise of the dentist should guide treatment for each case.

In vitro study examines posterior torque impact on 3D mechanics of anterior teeth in clear aligner treatment.

INTRODUCTION: This study utilizes investigate the impact of posterior torques on the three-dimensional force exerted on the lower anterior teeth during the retraction in orthodontic clear aligners treatment. METHODS: Four groups of mandibular dental arch light-cured resin models will be created, including: mandibular posterior teeth with standard torque, mandibular posterior teeth with labial torque, and mandibular posterior teeth with lingual torque. Each group will consist of 12 sets of clear aligners. The aligners will be worn, and measurements will be taken using the six-axis measurement platform to evaluate the three-dimensional force exerted on the lower anterior teeth under various initial torques applied to the mandibular posterior teeth. SPSS 26.0 used for ANOVA analysis, α = 0.05 significance level. RESULTS: Comparing mandibular posterior teeth with standard torque to those with labial torque, no statistically significant changes were observed in buccolingual force. In the mesiodistal direction, mandibular incisors exhibited a significant decrease in distal force, while canines showed a significant increase. Both findings had a significance level of P < 0.05; Lingual torque on mandibular posterior teeth, compared to standard torque, led to a significant increase in lingual force for incisors and a significant increase in labial force for canines in the buccolingual direction (P < 0.05). Additionally, mandibular incisors exhibited a significant decrease in distal force in the mesiodistal direction (P < 0.05). CONCLUSION: Varying initial torques on mandibular posterior teeth significantly impact force on lower anterior teeth. Labial torque reduces lingual force on incisors and increases distal force on canines. Lingual torque increases lingual force on incisors and labial force on canines.

Comparison of the different methods of width estimation in unerupted canine and premolars.

BACKGROUND: There are different methods for determining the required space for unerupted teeth. However, the accuracy of these techniques varies depending on ethnic differences. Therefore, the current study was performed to compare the accuracy of four methods for estimating the mesiodistal width of unerupted canines and premolars in a population of northern Iran. METHODS: The present cross-sectional study was conducted on 50 pairs of dental casts of patients aged 12-24 years old. The mesiodistal width of the teeth was measured with a digital caliper by two observers (ICC < 0.9), and the mean value was recorded. The space required for eruption of canines and premolars was obtained by the Tanaka-Johnson formula and the Moyers tables and compared with the actual value by paired t test. RESULTS: The Tanaka-Johnson formula had overestimation in the maxilla and mandible, which was statistically significant (p < 0.001). The values obtained from the Moyers tables in different confidence levels were not accurate. However, the 65% level for the mandible had almost no difference from the actual value (P = 0.996 and r2 = 0.503). Furthermore, linear regression was obtained based on the total mesiodistal width of the maxillary first molar and mandibular central incisor (maxilla: Yx= 0.613X + 2.23 and mandible: Ym= 0.618X + 1.6) and the total mesiodistal width of the mandibular first molar and maxillary central incisor in each jaw (maxilla: Yx = 0.424X + 5.021 and mandible: Ym = 0.447X + 3.631). CONCLUSION: The Tanaka-Johnson method was overestimated in the population of northern Iran. The 85% and 75% confidence levels of the Moyers table have the best clinical results for the maxilla and mandible, respectively. Regression based on maxillary first molars and mandibular central incisors has better results.

Fully automated deep learning approach to dental development assessment in panoramic radiographs.

BACKGROUND: Dental development assessment is an important factor in dental age estimation and dental maturity evaluation. This study aimed to develop and evaluate the performance of an automated dental development staging system based on Demirjian's method using deep learning. METHODS: The study included 5133 anonymous panoramic radiographs obtained from the Department of Pediatric Dentistry database at Seoul National University Dental Hospital between 2020 and 2021. The proposed methodology involves a three-step procedure for dental staging: detection, segmentation, and classification. The panoramic data were randomly divided into training and validating sets (8:2), and YOLOv5, U-Net, and EfficientNet were trained and employed for each stage. The models' performance, along with the Grad-CAM analysis of EfficientNet, was evaluated. RESULTS: The mean average precision (mAP) was 0.995 for detection, and the segmentation achieved an accuracy of 0.978. The classification performance showed F1 scores of 69.23, 80.67, 84.97, and 90.81 for the Incisor, Canine, Premolar, and Molar models, respectively. In the Grad-CAM analysis, the classification model focused on the apical portion of the developing tooth, a crucial feature for staging according to Demirjian's method. CONCLUSIONS: These results indicate that the proposed deep learning approach for automated dental staging can serve as a supportive tool for dentists, facilitating rapid and objective dental age estimation and dental maturity evaluation.

Trueness evaluation of three intraoral scanners for the recording of maximal intercuspal position.

OBJECTIVES: This clinical study aimed to assess the trueness of three intraoral scanners for the recor-ding of the maximal intercuspal position (MIP) to provide a reference for clinical practice. METHODS: Ten participants with good occlusal relationship and healthy temporomandibular joint were recruited. For the control group, facebow transferring procedures were performed, and bite registrations at the MIP were used to transfer maxillary and mandibular casts to a mechanical articulator, which were then scanned with a laboratory scanner to obtain digital cast data. For the experimental groups, three intraoral scanners (Trios 3, Carestream 3600, and Aoralscan 3) were used to obtain digital casts of the participants at the MIP following the scanning workflows endorsed by the corresponding manufacturers. Subsequently, measurement points were marked on the control group's digital casts at the central incisors, canines, and first molars, and corresponding distances between these points on the maxillary and mandibular casts were measured to calculate the sum of measured distances (DA). Distances between measurement points in the incisor (DI), canine (DC), and first molar (DM) regions were also calculated. The control group's maxillary and mandibular digital casts with the added measurement points were aligned with the experimental group's casts, and DA, DI, DC, and DM values of the aligned control casts were determined. Statistical analysis was performed on DA, DI, DC, and DM obtained from both the control and experimental groups to evaluate the trueness of the three intraoral scanners for the recording of MIP. RESULTS: In the control group, DA, DI, DC, and DM values were (39.58±6.40), (13.64±3.58), (14.91±2.85), and (11.03±1.56) mm. The Trios 3 group had values of (38.99±6.60), (13.42±3.66), (14.55±2.87), and (11.03±1.69) mm. The Carestream 3600 group showed values of (38.57±6.36), (13.56±3.68), (14.45±2.85), and (10.55±1.41) mm, while the Aoralscan 3 group had values of (38.16±5.69), (13.03±3.54), (14.23±2.59), and (10.90±1.54) mm. Analysis of variance revealed no statistically significant differences between the experimental and control groups for overall deviation DA (P=0.96), as well as local deviations DI (P=0.98), DC (P=0.96), and DM (P=0.89). CONCLUSIONS: With standardized scanning protocols, the three intraoral scanners demonstrated comparable trueness to traditional methods in recording MIP, fulfilling clinical requirements.

One case of complicated crown root fracture of upper anterior teeth managed by multidisciplinary joint approaches.

Complicated crown root fracture is a serious combined fracture of the enamel, dentin, and cementum in dental trauma. The treatment method is complicated. During the procedure, the condition of pulp, periodontal, and tooth body should be thoroughly evaluated, and a multidisciplinary approach combined with sequential treatment is recommended. This case reported the different treatment and repair processes of one case of two affected teeth after complicated crown root fracture of upper anterior teeth, including regrafting of broken crown after flap surgery at the first visit, direct resin repair to remove broken fragments, and pulp treatment and post-crown repair at the second visit. After 18 months of follow-up, the preservation treatment of the affected teeth with complicated crown root fracture was achieved. Therefore, fragment reattachment and post-crown restoration are feasible treatment options for children with complicated crown root fracture.

Enamel Veneer Rehabilitation of a Premolar to an Incisor After Autotransplantation.

Tooth autotransplantation is one of the methods used for tooth loss rehabilitation in children. Premolars are usually used as autotransplants requiring esthetic alterations. The purpose of this paper is to present an innovative, alternative and inexpensive way to restore auto-transplanted teeth using the crown of the tooth of the recipient site. A seven-year-old male with a non-contributory medical history presented with an intrusion of his permanent maxillary right central incisor. The tooth underwent orthodontic extrusion using fixed appliances but eventually showed signs of ankylosis. At 10 years old, autotransplantation of a premolar to substitute the ankylosed incisor was undertaken. Six weeks after the autotransplantation, the premolar was restored to an incisor by modifying the extracted ankylosed tooth to a veneer for the transplanted tooth, providing functional and esthetic restoration. The patient has been followed up for two years without any complications. This technique can help clinicians restore autotransplants in an easy and esthetic manner.

Restoration of Complicated Crown-Root Fracture in a Primary Incisor with Fragment Reattachment.

In traumatic dental injuries in children, due to a lack of maturity to cope with the situation, pain intolerance, amount of treatment procedure, and parental anxiety, simplified and non-invasive treatment procedures, such as biologic restorations, are useful. Using advanced adhesive material for fragment reattachment provides excellent esthetic results and a positive attitude from the patient and family. The purpose of this case report is to describe the biological restoration of a complicated crown-root fracture of a primary maxillary central incisor with the fragment reattachment technique.

Late Eruption of Mandibular Central Incisor in Small for-Gestational-Age Infants: A Cohort Study.

Purpose: To evaluate the chronology of the eruption of primary mandibular central incisors in infants born preterm and with low weight (PLBW) and its association with weight/length ratio for gestational age (GA) at birth, individual characteristics and hospitalization at birth. Methods: A cohort of 46 infants was followed at a multidisciplinary reference center at a university hospital in Belo Horizonte, Brazil. The inclusion criteria were infants born preterm with low/very low/extreme low birth weight and at least four months of age. Oral clinical examinations were carried out by a calibrated dentist for a total of eight months, with a one-month interval between each examination, to verify the chrono- logy of eruption of the primary mandibular central incisors. Caregivers completed a sociodemographic and health questionnaire. Data on neonatal hospitalization were collected from medical records. Data were analyzed with the Kaplan-Meier method and log rank test, and bivariate analysis was done using the Mann-Whitney method and Kruskal-Wallis test (P <0.05). Results: The average age at eruption of primary lower central incisors was 11 months for both sexes. No association was found between tooth eruption and child hospitalization or individual characteristics (P >0.05). Infants large for gestational age had earlier tooth eruption (9.3±1.41 months) than infants small for gestational age (13.6±3.29 months; P <0.05).Conclusion: The most likely age for the eruption of the first primary teeth in infants born preterm and with low weight was 11 months, and there was no influence of individual characteristics and hospitalization at birth. Small-for-gestational age infants experienced delayed tooth eruption compared to large-for-GA infants.