The Correlation Between Maxillary Central Incisor Dimensions and Different Points on the Face in a Syrian Population.

Statement of the Problem: When replacing the maxillary central incisor (MCI) or adjusting its dimensions, Syrian dentists may have difficulties in selecting the appropriate size due to the lack of a dental anthropometric database for Syrian society. Purpose: The purpose of this observational study was to investigate the correlation between MCI dimensions and face length and width in Syrian females and males. Materials and Methods: The study included 180 Syrian participants (90 females and 90 males) without facial or dental defects and aged between 20 and 25 years. A digital photograph of each individual's face was taken to measure face length and width. Maxillary stone casts were made for each individual to assess the MCI width and height using a digital caliper. The correlation between facial and dental variables was investigated with the Pearson correlation coefficient. Moreover, intersex variations were tested using an independent-sample t-test (p < 0.05 considered significant). Results: The mean MCI width was 8.58 mm, the mean MCI cervical width was 7.96 mm, the mean MCI height was 9.69 mm, the average MCI width-to-height ratio was 89%, and the average MCI cervical width-to-height ratio was 82%. The intersex variations in dental values were not statistically significant. None of the studied facial dimensions showed any significant correlation with any of the MCI measurements. Conclusion: The faces of Syrian men were larger than those of Syrian women, but their MCIs had similar proportions and sizes. Facial height and width were not the appropriate parameters for determining MCI size for Syrians.

Sex and Population Variations in Nasopalatine Canal Dimensions: A CBCT-Based Systematic Review.

The nasopalatine canal (NPC), an interosseous conduit in the anterior maxilla, plays a crucial role in various dental procedures, such as implant placement, orthodontics, and surgical interventions. Accurate anatomical characterization of the NPC is essential to avoid complications, as its morphometric variations can impact the nasopalatine nerve and vascular structures within the canal. Traditional radiography techniques are limited in displaying the canal's detailed anatomy due to issues like magnification and distortion. Cone beam computed tomography (CBCT), with its superior imaging quality and reduced radiation exposure, has become the preferred method for NPC evaluation. This systematic review aimed to evaluate the published literature on the variations in anatomy and dimensions of the NPC using CBCT. A complete literature search was conducted in Web of Science, PubMed/Medline, EMBASE, Scopus, Cochrane Library, Google Scholar, and ProQuest electronic databases. The following keywords were used alone or combined: CBCT, measurements [(nasopalatine canal length), (incisive foramen), (foramina of Stenson), (buccal bone plate), gender, plane as (oblique measurements), or (sagittal or axial). Papers were manually searched utilizing their reference titles. Research selection was restricted to the time of publication but not to the type of tested publication from different countries or sex and NPC parameter measurements. Fourteen full-length papers were included. Parameters like NPC length and diameters of incisive foramen (IF) and foramina of Stenson (FS) were generally higher in males than females, with significant differences noted across most studies. NPC dimensions are influenced by sex, with males typically exhibiting larger measurements. Additionally, NPC dimensions vary among different populations.

Three-dimensional assessment of the skeletal characteristics accompanying unilateral maxillary canine impaction: a retrospective cone-beam computed tomography study.

BACKGROUND: Environmental and genetic factors associated with canine impaction have been extensively researched, whereas the bone characteristics in the impaction area have not been thoroughly studied. Accordingly, the objective of this investigation was to provide a skeletal assessment in terms of bone density, bone microstructure, bone volume, and palatal volume in subjects with unilaterally impacted maxillary canines. METHODS: A retrospective design has been employed to address the aim of this study, where the initial pre-treatment cone-beam computed tomography (CBCT) scans of 30 patients with unilateral maxillary canine impaction were assessed. The obtained patients' data were equally divided according to the location of the impaction into 2 groups, one with buccally impacted canines, and another with palatal impactions, with the contra-lateral sides in both groups serving as the controls. Skeletal measurements such as bone density (BD), bone microstructure in terms of fractal dimension (FD), maxillary bone volume (MBV), and palatal volume (PV) were evaluated from the acquired CBCTs in both groups and compared to the controls. RESULTS: With buccal impactions, significantly greater BD and FD have been reported (p < 0.001), whereas non-significant differences were found regarding the PV when compared with controls (p = 0.56). MBV was significantly greater on the non-impaction side in comparison with buccal impaction sides (p < 0.001). For palatal impactions: BD, FD, and MBV were significantly greater on the impaction sides (p < 0.001), and conversely with PV which has been reported to be significantly greater on the non-impaction sides (p < 0.001). CONCLUSIONS: As per the obtained results, buccally impacted canines are associated with greater BD and FD, and less MBV, whereas palatally impacted canines are accompanied with greater BD, FD, and MBV, in addition to less PV, when both conditions are compared with the non-impaction sides.

Effect of soft tissue volume on midfacial gingival margin alterations following immediate implant placement in the esthetic zone: a 1-year randomized clinical and volumetric trial.

BACKGROUND: The current trial evaluated the midfacial gingival margin changes, volumetric, radiographic and clinical alterations 1-year following immediate implant placement with customized healing abutment (IIP + CHA) either solely, or in combination with xenograft (IIP + Bonegraft) or with connective tissue grafting (IIP + CTG) at sites with thin labial bone in the esthetic zone. METHODS: Thirty-nine non-restorable maxillary teeth indicated for extraction in the esthetic zone were included. Participants were randomly assigned into three equal group; IIP + Bonegraft (Control), IIP + CTG and IIP + CHA. Midfacial gingival margin changes(mm) as primary outcome, labial soft tissue contour change(mm), interdental tissue height changes and total volume(mm3) were assessed. Amount of bone labial to the implant and crestal bone level changes were also recorded. All outcomes were measured 1-year post-operative. RESULTS: The midfacial gingival margin changes demonstrated a significant difference (P ≤ 0.05) between the groups showing -0.98, -0.74 and -1.54 mm in sites treated with IIP + Bone graft, IIP + CTG and IIP + CHA respectively after1-year. While labial soft tissue contour change (mm), total volume (mm3) and distal interdental tissue height changes (mm) revealed a significant difference after one-year between the studied groups, yet mesial interdental tissue height changes showed no difference (P > 0.05). Both IIP + Bone graft and IIP + CHA groups revealed a significant positive correlation between the total volume loss (mm3) after 1 year and mid-facial gingival margin changes (P ≤ 0.05). However, no significant correlation was observed in the IIP + CTG group (P = 0.63). CBCT measurements showed a significant difference in crestal bone changes between the three groups (P ≤ 0.05), yet, there was no significant difference regarding mean amount of bone labial to the implant(P > 0.05). CONCLUSIONS: This investigation suggests that the mere presence of CTG simultaneous with IIP in the anterior maxilla reduced the midfacial gingival margin alterations (mm), besides, CTG decreased the overall volume loss (mm3) by 5-folds compared to the other studied groups after one year. Meanwhile, using CHA alone with IIP failed to maintain the peri-implant soft tissues contour. TRIAL REGISTRATION: The current trial was retrospectively registered at Clinical trials.gov (ID: NCT05975515, Date: 27-July-2023).

Comparison of AI-assisted cephalometric analysis and orthodontist-performed digital tracing analysis.

BACKGROUND: The aim of this study was to compare and evaluate three AI-assisted cephalometric analysis platforms-CephX, WeDoCeph, and WebCeph-with the traditional digital tracing method using NemoCeph software. MATERIAL AND METHOD: A total of 1500 lateral cephalometric films that met the inclusion criteria were classified as Class I, Class II, and Class III. Subsequently, 40 patients were randomly selected from each class. These selected films were uploaded to 3 AI-assisted cephalometric analysis platforms and analyzed without any manual intervention. The same films were also analyzed by an orthodontist using the NemoCeph program. RESULTS: The results revealed significant differences in key angular measurements (ANB, FMA, IMPA, and NLA) across Class I, II, and III patients when comparing the four cephalometric analysis methods (WebCeph, WeDoCeph, CephX, and NemoCeph). Notably, ANB (p < 0.05), FMA (p < 0.001), IMPA (p < 0.001), and NLA (p < 0.001) varied significantly. Linear measurements also differed, with significant differences in U1-NA (p = 0.002) and Co-A (p = 0.002) in certain classes. Repeated measurement analysis revealed variation in SNA (p = 0.011) and FMA (p = 0.030), particularly in the Class II NemoCeph group, suggesting method-dependent variability. CONCLUSION: AI-assisted cephalometric analysis platforms such as WebCeph, WeDoCeph, and CephX give rise to notable variation in accuracy and reliability compared to traditional manual digital tracing, specifically in terms of angular and linear measurements. These results emphasize the importance of meticulous selection and assessment of analysis methods in orthodontic diagnostics and treatment planning.

Palatal canine impaction is associated with craniofacial shape in humans.

BACKGROUND/OBJECTIVES: It is unclear whether palatal canine impaction is related to genetic or local/environmental factors. If a genetic origin is assumed, then it could be expected that palatal canine impaction is associated with overall craniofacial development. Within this context, the aim of this study was to evaluate the craniofacial morphology of individuals with palatal canine impaction and compare it to a matched group of normal controls. MATERIALS/METHODS: The sample for this investigation comprised 404 individuals (232 females and 172 males). Half of these individuals presented with unilateral or bilateral palatal canine impaction confirmed clinically and radiographically. The other half were matched for sex and age with the first half and comprised individuals without tooth impaction, apart from third molars. The shape of the craniofacial structures was outlined on calibrated cephalometric images through 15 curves and 127 landmarks (11 fixed and 116 semi-landmarks). Shape configurations were superimposed using Procrustes Superimposition and the resulting shape coordinates were reduced into principal components for all subsequent analyses. The effect of palatal canine impaction on craniofacial shape was assessed with regression models, separately in females and males. All statistical tests were performed assuming a type-1 error of 5%. RESULTS: Individuals with palatally impacted canines appear to have a less convex face, a more brachyfacial skeletal pattern, and a sagittally extended premaxilla. In females effect sizes ranged between η2 = 0.136-0.397 (P < 0.05) and in males between η2 = 0.125-0.396 (P < 0.05, apart from the entire craniofacial configuration: P = 0.259). LIMITATIONS: Palatal canine impaction was not confirmed through cone beam computer tomography images in all patients, however, in those cases, the treatment history confirmed the diagnosis. CONCLUSIONS/IMPLICATIONS: Palatal canine impaction is related to a distinct craniofacial shape in females and males. These findings allow for speculation that palatal canine impaction is affected by genetic pathways involved in overall craniofacial development.

Static Loading of Different Intraradicular Preparation Depths of Trinia Endocrowns in Maxillary Canines.

AIM: The aim of this study is to compare the fracture resistance of canine teeth restored using TRINIA Endocrowns with three different types of preparations (2, 3, and 4 intracanal preparations). MATERIALS AND METHODS: Thirty maxillary-extracted canines were collected. All teeth were fixed in orthodontic acrylic resin and decapitated at the level of the proximal cemento-enamel junction (CEJ). After being endodontically treated, specimens were distributed equally between 3 groups (n = 10) with different preparation depths (GT: 2 mm Intraradicular Preparation, GH: 3 mm Intraradicular Preparation, GF: 4 mm Intraradicular Preparation). Thirty TRINIA endocrowns were dry milled. After surface treatment, all endocrowns were bonded to their corresponding roots using Permaflo a dual-cure resin cement. Each specimen was then fixed in the lower part of a universal testing machine with a load cell of 5 KN, at an angle of 45 degrees to the tooth long-axis at 0.5 mm/min crosshead speed. Failure loads were recorded in Newton's. Data were recorded, organized, and statistically investigated. RESULTS: Shapiro-Wilk tests revealed that the data were not normally distributed. Descriptive statistics revealed a high mean fracture resistance of GH (647 N), then GT (475.6 N), and finally GF (353.9 N). The Kruskal-Wallis test revealed a significant difference that existed between the groups being studied (p = 0.036). CONCLUSION: TRINIA endocrowns with intracanal preparations of 2 and 3 mm provide more promising fracture resistance than those with intracanal preparations of 4 mm as a way of treating of root-canal-treated maxillary canines. TRINIA endocrowns (2 and 3 mm intracanal preparations) are as promising as fiber posts and all ceramic crowns in terms of fracture resistance. TRINIA endocrowns with 2 mm intracanal preparations are mostly reparable after failure, but those of 3 and 4 mm are mostly irreparable after failure. CLINICAL SIGNIFICANCE: Modifying endocrowns to have intraradicular projections, simulating Nayyar core, may improve the success and longevity of endocrowns in anterior teeth. How to cite this article: Alahmad AM, Alenezi AY, Rayyan M, et al. Static Loading of Different Intraradicular Preparation Depths of Trinia Endocrowns in Maxillary Canines. J Contemp Dent Pract 2024;25(6):575-580.

Focus on leveling the hidden: managing impacted maxillary canines.

INTRODUCTION: The long pathway that the canines take as they emerge into the maxillary arch makes them vulnerable to disruption during their natural emergence time. The process of planning treatment for impacted maxillary canine (IMC) presents significant challenges, underscoring the need for careful consideration and expertise. OBJECTIVE: The aim of this article was to shed light on these complexities by discussing clinical case studies involving IMC, providing insights into the intricacies of their management. CONCLUSIONS: The management of IMC within orthodontics presents a multifaceted challenge that include the necessity for precise diagnostic processes, prudent use of cone beam computed tomography (CBCT), the strategic selection between open and closed exposure techniques, a in-depth understanding of the specific orthodontic biomechanics involved, and a keen awareness of potential adverse outcomes such as ankylosis, prolonged treatment times, root resorption, and additional complications.

Anchorage loss of the posterior teeth under different extraction patterns in maxillary and mandibular arches using clear aligner: a finite element study.

BACKGROUND: Extracting the premolars is an effective strategy for patients with bimaxillary dentoalveolar protrusion. Clear aligners (CAs) close the extraction spaces through shortening the length of aligners. The contraction force generated by the terminal of aligners makes the posterior teeth tip mesially, which is known as the roller coaster effect. This phenomenon is even worse in the 2nd premolar extraction cases. Posterior anchorage preparation is commonly used to protect the angulation of molars, taking the form of presetting distal tipping value. However, the distal tipping design aggravates the anchorage loss of anterior teeth simultaneously. This study aimed to explore the different anchorage loss of the posterior teeth when the 1st or 2nd premolars were extracted using CAs, respectively in maxillary and mandibular arches, further providing guidance for anchorage preparation design in clinical practice. METHODS: Two bimaxillary finite element models with different extraction patterns were established to simulate the anterior en-masse retraction process of the CAs. In Model 1, the maxillary and mandibular 1st premolars were extracted, while in Model 2, the 2nd premolars were extracted. Finite element analysis methods were utilized to analyze the tipping angle of the anterior and posterior teeth. RESULTS: Compared between two models, the anterior teeth exhibited a greater lingual inclination tendency and the posterior teeth exhibited a slighter mesial tipping tendency in Model 1 regarding individual tooth. The closer to the extraction spaces, the greater the tip, and the distal tipping tendency of the 1st premolars was more evident than the mesial tipping tendency of the 1st molars in Model 2. Compared between the maxillary and mandibular arches, the mesial tipping tendency of individual posterior tooth was more evident in the maxilla. In addition, the highest hydrostatic stress of the periodontal ligaments was concentrated on the cervical and apical parts directly adjacent to the extraction spaces, and it exhibited relatively uniform distribution in Model 1. CONCLUSIONS: The individual posterior tooth showed the same mesial tipping direction but to different degree when the 1st or the 2nd premolars were extracted during clear aligner treatment. Presetting anchorage preparation design for the posterior teeth is essential to alleviate the roller coaster effect, especially in the 2nd premolar extraction cases. Furthermore, larger anchorage preparation value should be proposed for the maxillary posterior teeth.

Alveolar regeneration of the post-extraction site with cortical deficiency using the Lamina Socket Sealing technique: A retrospective study with clinical, radiographic and histomorphometric analysis. Part 1/2.

PURPOSE: This retrospective observational study aims to evaluate the outcome of a new alveolar ridge preservation (ARP) technique, "Lamina Socket Sealing" (LSS) technique, using a porcine barrier. METHODS: 36 subjects with maxillary premolars to be extracted and extensive alveolar wall defects were enrolled and treated. Porcine-derived barriers and mesenchymal membrane were used to seal the extraction socket with alveolar particulate graft. The outcome variables were: radiographical bone changes and clinical outcomes. RESULTS: 36 subjects, 21 females and 15 males were treated. The change in mm (mean + SE) of horizontal ridge width from baseline to 4 months after surgery at the coronal level of the alveolus was +1.25 ± 0.20 mm (P< 0.05), mean level was +0.34 ± 0.1 mm (P< 0.05) and at the apical level was +0.08 ± 0.17 mm (P> 0.05) which was not statistically significant. The buccal and palatal height changes in mm (mean + SE) from baseline to 4 months after surgery were respectively 1.21 ± 0.17 mm for the buccal wall (P< 0.05) and 1.06 ± 0.24 mm for the palatal wall (P< 0.05). The bone volume of all sites allowed for the placement of the planned implants. CLINICAL SIGNIFICANCE: The alveolar ridge preservation technique (Lamina Socket Sealing) using resorbable heterologous cortical lamina with flapless approach allowed not only the preservation of the damaged post-extraction socket, but also minimal ridge augmentation, according to the principles of guided bone regeneration.

Comparison of Needle Depth Techniques for the Posterior Superior Alveolar Block.

Purpose The posterior superior alveolar (PSA) block injection is one of many techniques used to provide profound anesthesia for invasive dental procedures. This technique has a high success rate but is not without complication risks. The purpose of this study was to determine if pulpal anesthesia of the maxillary second molar could be achieved using a reduced needle depth of 10mm or 5mm compared to the traditional needle depth of 16mm.Methods Sixty participants were asked to participate in three sessions. Each session started with a pre neural response test, followed by one randomized needle depth PSA injection, and ending with a post neural response test. The neural response test consisted of two parts, a cold refrigerant and a dental probe, on the buccal and interproximal surface of the maxillary second molar. After receiving a positive neural response, each participant received a posterior superior alveolar block injection using a short (21mm), 27-gauge dental needle with a randomized needle penetration depth of 16mm, 10mm, or 5mm. A post neural response test consisting of the same two parts as the pre-test was conducted on the maxillary second molar to evaluate for profound anesthesia.Results Positive neural responses were obtained from 100% of the participants (n=167) during the pre-tests. Study results demonstrated an 85% success rate at the traditional 16mm needle depth and a 93% and 92% success rates for the reduced needle depths of 10mm and 5mm, respectively. Pulpal anesthesia of the maxillary second molar had been achieved at all three needle depths with no statistically significant difference in the rate of success. Furthermore, there were no adverse events observed.Conclusion The reduced needle depth technique showed promise in achieving desired results of pulpal anesthesia with a reduced risk for complications associated with the PSA block injection. Additional studies are recommended to achieve evidence-based support for this reduced needle depth technique.

Root Canal Morphology of Premolars in Population of Hyderabad, Pakistan: A Cone Beam Computerised Tomographic Analysis.

OBJECTIVE: To investigate the mean tooth length and root canal configuration of human maxillary and mandibular premolars in the population of Hyderabad, Pakistan, using Cone Beam Computed Tomography (CBCT). STUDY DESIGN: Observational study. Place and Duration of the Study: Department of Operative Dentistry and Endodontics, Liaquat University of Medical and Health Sciences, Jamshoro, Sindh, Pakistan, from December 2022 to March 2023. METHODOLOGY: Using retrospective analysis of CBCT scans, tooth length, the number of roots, and root canal configuration of 536 mandibular and maxillary premolars were assessed in the subpopulation of Pakistan. The data were analysed employing descriptive statistics, Chi-square tests, and One-Way ANOVA to determine the association between various factors and root canal morphology. RESULTS: Vertucci Type 1 (one canal) was the most common configuration in maxillary premolars, with frequencies ranging from 46.3 to 52.2%. The mean length of all 8 premolars ranged from 20.56 mm to 21.58 mm. C-shaped canal configurations were observed in a small percentage of maxillary and mandibular premolars, with C1 being the most common. No significant association was found between gender and canal configuration or tooth length, and in tooth lengths among different canal configurations. CONCLUSION: Vertucci Type 1 was the most common configuration in maxillary premolars, followed by Vertucci Type 4. Single-rooted premolars were more prevalent, while two-root configurations were less common. C-shaped canal configurations were observed in a small percentage of premolars, with higher frequency in mandibular premolars. KEY WORDS: Cone beam computed tomography, Dental anatomy, Endodontics, Premolars, Root canal morphology.

Longitudinal study of root resorption on incisors caused by impacted maxillary canines-a clinical and cone beam CT assessment.

OBJECTIVE: To evaluate the long-term status of incisors with canine-induced root resorption (CIRR). MATERIALS AND METHODS: Subjects with impacted maxillary canines (IMC) and persisting incisors with CIRR examined with cone beam computed tomography (CBCT), diagnosed ≥ 5 years earlier, were recalled. The resorption grade in the horizontal and vertical plane was assessed on CBCT images at baseline (T0) and follow-up (T1). Clinical examination was done at T1 which included probing depth, gingival retraction, mobility, ankylosis, discoloration and vitality test. In addition, patients completed a questionnaire regarding symptoms from the incisors. RESULTS: Forty subjects (mean age 13.7 ±â€…2.1 years) with 43 IMC and 47 incisors with CIRR were recruited. The IMC either spontaneously erupted, were surgically exposed or surgically removed. Thirty-four of the patients were treated with a fixed appliance and six had no orthodontic treatment. The follow-up range was 5.5-14.6 years. None of the incisors were lost or endodontically treated at T1. The horizontal resorption grade was unchanged in 38, improved in 7, and worsened in 2 teeth. The corresponding results for the vertical resorption grade were unchanged in 20 and worsened in 27 teeth. Three incisors with severe horizontal resorption at T0 were significantly more obliterated at T1 (P = .01). No significant differences were found in clinical parameters or patient-reported outcomes between incisors with CIRR and non-resorbed contralateral incisors at T1. LIMITATIONS: The extent of root resorption during active orthodontic treatment was not possible to assess as only CBCT images from T0 and T1 were available. CONCLUSION: Incisors with CIRR caused by IMC have a high survival rate in a long-term perspective and do not cause more symptoms or exhibit more signs of pathology than non-resorbed contralateral incisors. Extraction of asymptomatic incisors based solely on root resorption should not be performed routinely.

Biomechanical evaluation of six zygomatic implants versus four zygomatic implants combined with dental implants in the treatment of different maxillary defects.

BACKGROUND: This study aims to compare the biomechanics of six zygomatic implants (ZIs) and dental implants (DIs) combined with four ZIs with different maxilla defects. METHODS: Three-dimensional constructs of the ZIs, DIs human skulls, and maxillary prostheses were created using SolidWorks Software (Version 2015, Dassault Systems SolidWorks Corporation, Waltham, MA, USA). Eight finite element models of the skull with four different alveolar defect types (0-4) were constructed. Type 0: No defect; Type 1: Bilateral posterior defects; Type 2: Right posterior defect; Type 3: Anterior and left posterior defects; Type 4: Bilateral posterior and anterior defects. In two models with the same defect type (for defect types 0-2), six ZIs or two DIs combined with four ZIs were inserted into the maxilla. Six ZIs were inserted in the maxilla models with defect types 3 and 4. Vertical (150 N) and masseteric (300 N) loads were simulated on the prosthesis. The maximum Von Mises stress in the implants/surrounding bone and bone deformation were evaluated. RESULTS: The maximum Von Mises stresses in bone/implant were found highest in the defect type 2 model with four ZIs combined with two DIs. The lowest maximum Von Mises stress for bone was detected in the model with defect type 0 and with six ZIs. CONCLUSION: Among the four types of defects, the posterior unilateral defect caused the highest stress value.

Three-dimensional Analysis of Skeletal Stability in Cleft Lip and Palate Patients Undergoing Bimaxillary Surgery With Le Fort I Osteotomy and Intraoral Vertical Ramus Osteotomy.

Orthognathic surgery in patients with lip and palate clefts is challenging owing to scar tissue from primary repairs and severe deformities. In this study, we evaluated the stability of Le Fort I osteotomy with intraoral vertical ramus osteotomy (IVRO) in patients with cleft lip and palate using 3-dimensional (3D) analysis. This retrospective study comprised 14 cleft lip and palate patients (3 females, 11 males; the average age at surgery: 23.8 y) who underwent bimaxillary orthognathic surgery involving Lefort I osteotomy and IVRO. Cone-beam computed tomography (CBCT) images were obtained at preoperative (T0), 1-month postoperative (T1), and 1-year follow-up (T2) periods. The 3D analysis assessed the transitions and rotations of the maxilla and mandible using a virtual triangle. The maxilla showed stability in all directions at the 1-year follow-up with minimal relapse. The distal segment of the mandible exhibited clinically acceptable anterior (1.15 mm relapse) movements and pitch rotation (2.88° counterclockwise relapse) during the first year postoperatively. The proximal mandibular segment underwent anterior-inferior transition (1.21 and 2.01 mm, respectively) and lateral-outward rotation (4.90° and 7.51°, respectively) postsurgery, remaining unchanged 1 year postoperation. Le Fort I osteotomy with IVRO provides skeletal stability in patients with cleft lips and palates. This study demonstrated a minimal maxillary relapse and clinically acceptable movements in the distal mandibular segment during the first postoperative year. The proximal mandibular segment moved anteriorly and inferiorly, rotated laterally and outward after surgery, and remained unchanged at the 1-year follow-up.

Development and validation of a robotic system for milling individualized jawbone cavities in oral and maxillofacial surgery.

OBJECTIVES: This study aimed to develop and validate a robotic system capable of performing accurate and minimally invasive jawbone milling procedures in oral and maxillofacial surgery. METHODS: The robotic hardware system mainly includes a UR5E arm (Universal Robots, Denmark) and the binocular positioning system (FusionTrack 250, Atracsys LLC, Switzerland). The robotic software (Dental Navi 3.0.0, Yakebot Technology Ltd., China) is capable of generating cutting tool paths based on three-dimensional shape description files, typically in the stereolithography format, and selected cutting tool parameters, as well as designing surgical accessories. Fully impacted supernumerary tooth models in the maxilla were fabricated using software and three-dimensional printing. Following the planning of a customized cavity to fully expose the tooth, maxillary bone milling was performed on both the robot and static guide groups (n = 8). After milling, all models underwent scanning for assessment. RESULTS: In the experiment with fully buried supernumerary tooth models in the maxilla, the root mean square, translation error, over-removal rate, and maximum distance were significantly smaller in the robot group compared to the static guide group. Moreover, the overlap ratio and Dice coefficient were significantly greater in the robot group. No statistically significant differences were observed between the two groups in terms of the rotation error (P = 0.80) or under-removal rate (P = 0.92). CONCLUSIONS: This study has developed a robotic system for milling individualized jawbone cavities in oral and maxillofacial surgery, and its accuracy has been preliminarily verified to meet clinical requirements. CLINICAL SIGNIFICANCE: The robotic system can achieve precise, minimally invasive, individualized jawbone milling in a variety of oral and maxillofacial surgeries, including tooth autotransplantation, surgical reshaping for zygomatic fibrous dysplasia, removal of fully impacted supernumerary or impacted teeth, and endodontic microsurgery, among other relevant clinical applications.

Evaluation of anterior teeth crown-root morphology and alveolar bone structure in patients with closed deep overbite using cone beam computed tomography.

This retrospective study used cone-beam computed tomography to investigated the crown-root morphology and alveolar bone structure in incisors region in subjects with closed deep overbite and comparison the difference between gender and age. The CBCT images for 40 subjects (group C) with Angle II division 2 were selected from patients of the HeFei Stomatological Hospital from November 2023 to March 2024.20 individual normal occlusion subjects (group A),20 patients with Angle II division 1(group B) were included. The crown-root ratio of the maxillary and mandibular anterior teeth, crown-root angle and alveolar bone structure were measured on the CBCT images, the data were statistically analyzed. In addition to mandibular lateral incisor, the crown-root ratio of maxillary and mandibular anterior teeth in the Class II division 2 group was higher than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The crown-root angle of maxillary anterior teeth in the Class II division 2 group was smaller than that in the individual normal occlusion group and the Class II division 1 (P < 0. 05). The alveolar bone thickness of the maxillary central incisor was comparatively smaller, while the alveolar bone height was relatively higher in the Class II division 2 group. Age and gender were associated with change in root lengths and crown-root angle for the Class II division 2 group (P < 0. 05). Patients with closed deep overbite malocclusion exhibit a significant difference compared to the controls for most measurements. The patients presenting with Class II division 2 malocclusion exhibit excessive inward positioning of the anterior teeth, resulting in evident crown-root angle, a large crown-root ratio, and minimal labial alveolar bone. In order to keep the tooth movement within the safe range of alveolar bone movement, it is necessary to strictly control the torque and use appropriate orthodontic force to reduce the risk of bone fenestration, bone dehiscence, gingival recession and root resorption.

Dentofacial and skeletal effects of two orthodontic maxillary protraction protocols: bone anchors versus facemask.

BACKGROUND: Maxillary retrognathia and/or mandibular prognathia are resulting in class III malocclusion. Regarding orthodontic class III malocclusion treatment, the literature reports several treatment approaches. This comparative clinical study investigated two maxillary protraction protocols including bone anchors and Delaire type facemask. METHODS: Cephalometric radiographs of n = 31 patients were used for data acquisition. The patients were divided into two groups according to their treatment protocol: bone anchored protraction (n = 12, 8 female, 4 male; mean age 11.00 ± 1.76 years; average application: 13.50 ± 5.87 months) and facemask protraction (n = 19, 11 female, 8 male; mean age 6.74 ± 1.15 years; average application: 9.95 ± 4.17 months). The evaluation included established procedures for measurements of the maxilla, mandibula, incisor inclination and soft tissue. Statistics included Shapiro-Wilk- and T-Tests for the radiographs. The level of significance was set at p < 0.05. RESULTS: The cephalometric analysis showed differences among the two groups. SNA angle showed significant improvements during protraction with bone anchors (2.30 ± 1.18°) with increase in the Wits appraisal of 2.01 ± 2.65 mm. SNA angle improved also during protraction with facemask (1.22 ± 2.28°) with increase in the Wits appraisal of 1.85 ± 4.09 mm. Proclination of maxillary incisors was larger in patients with facemask (3.35 ± 6.18°) and ML-SN angle increased more (1.05 ± 1.51°) than in patients with bone anchors. Loosening rate of bone anchors was 14.58%. CONCLUSIONS: Both treatment protocols led to correction of a class III malocclusion. However, this study was obtained immediately after protraction treatment and longitudinal observations after growth spurt will be needed to verify the treatment effects over a longer period. The use of skeletal anchorage for maxillary protraction reduces unwanted side effects and increases skeletal effects needed for class III correction.

[Experience in the use of zygomatic implants combined with traditional dental implants in the case of severe atrophy of the alveolar process of the upper jaw]. / Opyt primeneniya skulovykh implantatov, kombinirovannykh s traditsionnymi dental'nymi implantatami, v sluchae vyrazhennoi atrofii al'veolyarnogo otrostka verkhnei chelyusti.

Rehabilitation of patients with adentia and severe atrophy of the alveolar process of the upper jaw is one of the most difficult tasks of modern dentistry. The article demonstrates the experience of using a combination of traditional dental and zygomatic implants to create a fixed prosthesis support on the upper jaw. The combined installation of standard and zygomatic implants is a predictable rehabilitation technique in the case of severe atrophy of the alveolar process of the upper jaw, which reduces the number of surgical stages and reduces the duration of treatment.