Clinical accuracy of partially guided implant placement in edentulous patients: A computed tomography-based retrospective study.

OBJECTIVES: This retrospective study was intended to evaluate the clinical accuracy of partially guided template in guiding implant placement in edentulous patients. METHODS: A total of 120 implants were placed in 24 patients with at least one completely edentulous arch with a partially guided system. Based on CBCT data, a repeatable method was used to measure linear and angular deviations of implants at 3D level in Mimics medical software. The influence of supporting tissue and implant region on the accuracy was assessed, followed by the evaluation of direction of linear deviations in biologically vital areas. RESULTS: Linear deviations of all implants were 1.91 ± 0.68 mm, 1.47 ± 0.68 mm, and 1.02 ± 0.69 mm at apical, apical lateral, and apical vertical levels. When at the cervical, cervical lateral, and cervical vertical levels, the linear deviations were 1.53 ± 0.65 mm, 0.98 ± 0.53 mm, and 1.01 ± 0.69 mm, respectively. Angular deviation of all implants was 7.14 ± 3.41°. Implants guided by mucosa + tooth-supported templates showed higher linear deviations at apical vertical level (1.21 ± 0.72 mm vs. 0.86 ± 0.63 mm, p < .05) and cervical vertical level (1.18 ± 0.72 mm vs. 0.87 ± 0.63 mm, p < .05) than mucosa-supported templates, and implants in maxilla were found higher angular deviation than mandible (7.89 ± 3.61° vs. 6.29 ± 2.97°, p < .05). CONCLUSIONS: The partially guided template served as clinically viable surgical assistance in implant placement in edentulous patients. When using mucosa + tooth-supported template or placing implants in maxilla, more caution was required, especially in biologically vital areas.

A unilateral increase in the occlusal vertical dimension of growing rats results in mandibular deviation.

OBJECTIVE: The effects of unilateral increased occlusal vertical dimension (iOVD) on bilateral craniofacial, mandibular and alveolar development in growing rats were investigated via cone-beam computed tomography (CBCT). The role of Wnt/ß-catenin signalling in this process was examined. MATERIALS AND METHODS: Forty-eight female Sprague-Dawley rats were randomly allocated into unilateral iOVD and sham groups. At 2, 4 and 8 weeks, the rats were scanned via CBCT to analyse cranial, maxillary, mandibular and dental morphology. Changes in temporomandibular joint (TMJ) cartilage histology and Wnt/ß-catenin signalling were assessed by histochemical and immunohistochemical staining and qRT-PCR. RESULTS: Dorsal cephalograms revealed that the mandible in the iOVD group tilted approximately 4° to the right. Unilateral iOVD had little effect on cranial and maxillary growth but inhibited mandibular growth (mandibular length and ramal height), especially on the deviated side (DS). Moreover, unilateral iOVD increased the length of the lower incisors and decreased the height of the molars on the DS. Unilateral iOVD induced bilateral osteoarthritis-like changes in the bilateral TMJ condylar cartilage and activated Wnt/ß-catenin signalling in the condylar cartilage, especially on the contralateral side (CLS). CONCLUSION: Occlusion with unilateral iOVD induced mandibular deviation, significantly inhibited mandibular growth and produced compensatory changes in the alveolar bone. In the iOVD group, the mandibular body length and ramal height were greater on the CLS than on the DS. Moreover, the greater ß-catenin protein expression in the TMJ condylar cartilage on the CLS than on the DS may account for the difference in asymmetrical mandibular development.

Accuracy of an autonomous dental implant robotic system in partial edentulism: A pilot clinical study.

OBJECTIVES: Robots are increasingly being used for surgical procedures in various specialties. However, information about the accuracy of robot-assisted dental implant surgery is lacking. This pilot clinical study aimed to investigate the accuracy of an autonomous dental implant robotic (ADIR) system in partially edentulous cases. MATERIAL AND METHODS: The ADIR system was used to place a total of 20 implants in 13 participants. Implant deviation from the planned positions was assessed to determine accuracy. The entry, apex, and angular deviations were described as means ± standard deviation. A two-sample t test was used to compare implant deviation between the flap and flapless groups and between maxillary and mandibular implants (α = .05). RESULTS: The entry, apex, and angular deviations were 0.65 ± 0.32 mm, 0.66 ± 0.34 mm, and 1.52 ± 1.01°, respectively, with no statistically significant difference between the flap and flapless approaches (P > .05). No adverse events were encountered in any of the participants. CONCLUSIONS: DIR accuracy in this clinical series was comparable to that reported for static and dynamic computer-assisted implant surgery. Robotic computer-assisted implant surgery may be useful for dental implant placement, potentially improving the quality and safety of the procedure. CLINICAL RELEVANCE: The findings of this study showed that the ADIR system could be useful for dental implant surgery.

Predicting masticatory muscle activity and deviations in mouth opening from non-invasive temporomandibular joint complex functional analyses.

BACKGROUND: A quantitative approach to predict expected muscle activity and mandibular movement from non-invasive hard tissue assessments remains unexplored. OBJECTIVES: This study investigated the predictive potential of normalised muscle activity during various jaw movements combined with temporomandibular joint (TMJ) vibration analyses to predict expected maximum lateral deviation during mouth opening. METHOD: Sixty-six participants underwent electrognathography (EGN), surface electromyography (EMG) and joint vibration analyses (JVA). They performed maximum mouth opening, lateral excursion and anterior protrusion as jaw movement activities in a single session. Multiple predictive models were trained from synthetic observations generated from the 66 human observations. Muscle function intensity and activity duration were normalised and a decision support system with branching logic was developed to predict lateral deviation. Performance of the models in predicting temporalis, masseter and digastric muscle activity from hard tissue data was evaluated through root mean squared error (RMSE) and mean absolute error. RESULTS: Temporalis muscle intensity ranged from 0.135 ± 0.056, masseter from 0.111 ± 0.053 and digastric from 0.120 ± 0.051. Muscle activity duration varied with temporalis at 112.23 ± 126.81 ms, masseter at 101.02 ± 121.34 ms and digastric at 168.13 ± 222.82 ms. XGBoost predicted muscle intensity and activity duration and scored an RMSE of 0.03-0.05. Jaw deviations were successfully predicted with a MAE of 0.9 mm. CONCLUSION: Applying deep learning to EGN, EMG and JVA data can establish a quantifiable relationship between muscles and hard tissue movement within the TMJ complex and can predict jaw deviations.

Influence of parallel pins on the angle deviation for placement of dental implants: an in vitro study.

The aim of the present study was to analyze and compare the angle deviation of two, four and six adjacent dental implants placed with and without straight parallel pins. MATERIALS AND METHODS: Two hundred and forty (240) dental implants were selected and randomly allocated into the following study groups: Two dental implants placed with straight parallel pins (Ref.: 144-100, BioHorizons, Birmingham, AL, USA) (n = 10) (2PP); Two dental implants placed without parallel pins (n = 10) (2withoutPP); Four dental implants placed with straight parallel pins hT(n = 10) (4PP); Four dental implants placed without parallel pins (n = 10) (4withoutPP); Six dental implants placed with straight parallel pins (n = 10) (6PP) and Six dental implants placed without parallel pins (n = 10) (6withoutPP). The dental implants randomly assigned to groups 2PP and 2withoutPP were placed into standardized polyurethane models of partially edentulous upper jaws in tooth positions 2.4 and 2.6, the dental implants randomly assigned to groups 4PP and 4withoutPP were placed into standardized polyurethane models of fully edentulous upper jaws in tooth positions 1.6, 1.4, 2.4 and 2.6, and the dental implants randomly assigned to groups 6PP and 6withoutPP were placed into standardized polyurethane models of fully edentulous upper jaws in tooth positions 1.6, 1.4, 1.2, 2.2, 2.4 and 2.6. Afterwards, postoperative CBCT scans and digital impressions were aligned in a 3D implant-planning software to compare the angle deviation (°) of two, four and six adjacent dental implants placed with and without straight parallel pins using the General Linear Model statistical analysis. RESULTS: Statistically significant differences were found between the angle deviation of 2 dental implants placed with straight parallel pins (p < 0.0001) and between the angle deviation of 4 dental implants placed with straight parallel pins (p = 0.0024); however, no statistically significant differences were found in the angle deviation of 6 dental implants placed with straight parallel pins (p = 0.9967). CONCLUSION: The use of a straight parallelization pin results in lower angle deviation between two and four adjacent dental implants; however, it is not effective for a larger number of dental implants.

Accuracy evaluation of dental CBCT and scanned model registration method based on pulp horn mapping surface: an in vitro proof-of-concept.

BACKGROUND AND AIM: 3D fusion model of cone-beam computed tomography (CBCT) and oral scanned data can be used for the accurate design of root canal access and guide plates in root canal therapy (RCT). However, the pose accuracy of the dental pulp and crown in data registration has not been investigated, which affects the precise implementation of clinical planning goals. We aimed to establish a novel registration method based on pulp horn mapping surface (PHMSR), to evaluate the accuracy of PHMSR versus traditional methods for crown-pulp registration of CBCT and oral scan data. MATERIALS AND METHODS: This vitro study collected 8 groups of oral scanned and CBCT data in which the left mandibular teeth were not missing, No. 35 and No. 36 teeth were selected as the target teeth. The CBCT and scanned model were processed to generate equivalent point clouds. For the PHMSR method, the similarity between the feature directions of the pulp horn and the surface normal vectors of the crown were used to determine the mapping points in the CBCT point cloud that have a great influence on the pulp pose. The small surface with adjustable parameters is reconstructed near the mapping point of the crown, and the new matching point pairs between the point and the mapping surface are searched. The sparse iterative closest point (ICP) algorithm is used to solve the new matching point pairs. Then, in the C + + programming environment with a point cloud library (PCL), the PHMSR, the traditional sparse ICP, ICP, and coherent point drift (CPD) algorithms are used to register the point clouds under two different initial deviations. The root square mean error (RSME) of the crown, crown-pulp orientation deviation (CPOD), and position deviation (CPPD) were calculated to evaluate the registration accuracy. The significance between the groups was tested by a two-tailed paired t-test (p < 0.05). RESULTS: The crown RSME values of the sparse ICP method (0.257), the ICP method (0.217), and the CPD method (0.209) were not significantly different from the PHMSR method (0.250). The CPOD and CPPD values of the sparse ICP method (4.089 and 0.133), the ICP method (1.787 and 0.700), and the CPD method (1.665 and 0.718) than for the PHMSR method, which suggests that the accuracy of crown-pulp registration is higher with the PHMSR method. CONCLUSION: Compared with the traditional method, the PHMSR method has a smaller crown-pulp registration accuracy and a clinically acceptable deviation range, these results support the use of PHMSR method instead of the traditional method for clinical planning of root canal therapy.

Quantitative and qualitative condylar changes following stabilization splint therapy in patients with temporomandibular joint disorders with and without skeletal lateral mandibular asymmetry: a cone beam computed tomographic study.

BACKGROUND: Temporomandibular disorders (TMDs) encompass pain and dysfunction in the jaw, muscles, and adjacent structures. This study aimed to explore the quantitative (condylar position, morphology) and qualitative (bone mineral density (BMD)) therapeutic outcomes following a stabilization splint (S.S.) therapy in adult patients diagnosed with TMD (Arthralgia) with/without lateral mandibular asymmetry (MA) using cone beam computed tomography (CBCT). METHODS: In this retrospective clinical study, 60 adult TMD patients who received S.S. therapy were enrolled and allocated into the TMD group (TMDG) and TMD with MA group (TMD + MAG). The diagnosis was made according to the Diagnostic Criteria for TMD (DC/TMD) AXIS I. MA was measured from the mid-sagittal plane to the Menton point. CBCT was used to scan the temporomandibular joints pre- (T0) and post- (T1)-treatment for three-dimensional analysis. Intra- and intergroup statistical comparisons were performed using the Wilcoxon signed ranks and the Kruskal‒Wallis test. RESULTS: For quantitative comparisons, there was a statistically significant difference between T0 and T1 in the joint spaces of TMD + MAG (anterior, superior, posterior, and coronal lateral on the deviated side as well as in the superior, coronal medial joint space of the contralateral side). Morphologically, the deviated side had a narrower condylar width, reduced condylar height, and a steeper eminence angle. In contrast, the contralateral side tended to have a greater condylar length. For qualitative measurements, BMD also showed statistical significance between T0 and T1 in the majority of the condyle slopes (AS, SS, PS, and LS on the deviated side and in AS and MS on the contralateral side) of TMD + MAG. Additionally, only the AS and PS showed significance in TMDG. CONCLUSION: Multiple joint space widening (AJS and CMS) and narrowing (SJS, PJS, and CLS) could characterize the deviated side in TMD + MA. Factors like narrower condylar width, reduced condylar height, and steeper eminence angle on the deviated side can worsen TMD + MA. Proper alignment of the condyle-disc position is essential for optimal function and load distribution, potentially affecting bone mineral density (BMD). MA plays a prominent role in disturbing bone densities. S.S. therapy shows more evident outcomes in TMD + MAG (on the deviated side compared to the contralateral side) than the TMDG.

Analysis of the Application Value of Dynamic Navigation Guidance in Oral Implantation.

OBJECTIVE: To investigate the application of dynamic navigation guidance technology in different implantation scenarios, and to provide a scientific basis for the innovation and advancement of implantation techniques. METHODS: Fifteen cases of patients with malocclusions admitted between January 2021 and February 2023 were selected as the study subjects. All patients underwent dynamic navigation-guided oral implantation interventions. CBCT scans were taken after implantation surgery to record deviations of implantation points, including implantation point deviation, endpoint deviation, and angle deviation. RESULTS: Dynamic navigation guidance effectively improves the reliability and stability of implantation in oral implant patients. CBCT effectively evaluated the state of the patient's periodontal implant, analyzed the state of the patient's lesion area, and improved the quality of implant intervention through CBCT guidance. The implantation point deviation was (0.407±0.193) mm, the endpoint deviation was (0.492±0.201) mm, and the implant angle deviation was (2.162±0.283)°. There was no significant difference in implantation point deviation in the anterior and posterior parts of the upper and lower jaws after intervention (P>0.05). However, there were significant differences in endpoint deviation and implant angle deviation among the anterior and posterior parts of the upper and lower jaws (P<0.05). CONCLUSION: Dynamic navigation guidance effectively improves the reliability and stability of implantation in oral implant patients. However, there is relatively greater endpoint deviation and implant angle deviation in the posterior part of the upper jaw.

Three-dimensional evaluation of social smile asymmetry in patients with unilateral impacted maxillary canine: a 3D stereophotogrammetry study.

OBJECTIVE: This study aimed to evaluate social smile asymmetry in patients with unilateral impacted maxillary canine on 3D stereophotogrammetric images. MATERIAL AND METHODS: The 3D social smile images of participants with unilateral impacted maxillary canine (n:20) and without impaction as a control group (n:20) were included. The images were recorded with a hand-held 3D stereophotogrammetry device (Fuel3D® Scanify®) and Geomagic Essentials 2 reverse engineering software were used for analyses. After the orientation process of the 3D records, the tissues around the smile area were divided into five morphological regions: cheek, upper lip lateral and medial, and lower lip lateral and medial. The deviation margins in the negative and positive directions for the 95% mesh rate and the total percentages of meshes between - 0.5- and + 0.5-mm deviations were calculated. ICC, paired samples t test, independent samples t test, and the Mann-Whitney U test were used for statistical analyses. RESULTS: In individuals with impacted canine, the amount of maximum positive deviation in the upper lip medial was 5.64 mm ± 1.46 and maximum negative deviation was - 4.6 mm ± 1.17. In the control group, mean of deviation limits for all parameters was less than 1.19 mm ± 2.62, while in individuals with unilateral impacted maxillary canine, the maximum value was 8.34 mm ± 2.23. The mesh percentage between - 0.5 and 0.5-mm deviations was over 95% in all morphological areas in the control group, while in the impacted canine group, the number of meshes within the specified deviation limits was less than 95%. CONCLUSION: Individuals with unilateral impacted maxillary canine exhibit greater asymmetry in social smile compared to the control group, with the asymmetry being most prominent near the corners of the mouth and cheeks. CLINICAL RELEVANCE: Amount of asymmetry was higher in impaction group compared to the control group in social smile. The quantification of a possible smile asymmetry due to the impacted canine is crucial for the diagnosis and treatment planning of orthodontic and/or orthognathic cases for ideal aesthetic results. Hence, smile asymmetry should not be overlooked and should be considered in diagnosis and treatment planning.

Three dimensional evaluation of the skeletal and temporomandibular joint changes following stabilization splint therapy in patients with temporomandibular joint disorders and mandibular deviation: a retrospective study.

BACKGROUND: Three-dimensional (3D) detailed evaluations of the mandibular mediolateral position, mandibular condylar position, and temporomandibular joint (TMJ) spaces following stabilization splints (SS) therapy in patients with temporomandibular joint disorders (TMD) and mandibular deviation (MD) have not been reported in the available literature. Accordingly, this study aimed to three-dimensionally analyze the skeletal and bony temporomandibular joint changes following stabilization splint therapy in adult patients with temporomandibular joint disorders and mandibular deviation. METHODS: This study is a retrospective clinical study that enrolled 26 adult patients with TMD and MD with a mean age of 24.86 years. The Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) was used to diagnose TMD. SS was adjusted weekly until occlusal contact stabilization occurred, and then adjusted monthly, patients were instructed to wear it at night for at least 10 h. The SS was removed after the elimination of TMD symptoms (TMJ/muscle pain on palpation, muscle spasm, and clicking) and having both condyles completely seated in a musculoskeletally stable position. Pre- and post-therapeutic Cone Beam Computed Tomography (CBCT) was analyzed. Mandibular mediolateral position, TMJ spaces, and mandibular condyle position were analyzed three-dimensionally using Mimics 21.0 software. Paired t-test or Wilcoxon rank-sum test was performed, and the significance level was considered at P < 0.05. RESULTS: The treatment period with SS therapy was 10.07 ± 3.1 months. The deviated chin was improved in 69.23% of the sample; the range of improvement was > 0 mm ≤ 3.9 mm. The mandibular rotation was significantly decreased from 3.58 ± 2.02° to 3.17 ± 1.60. The deviated side's superior and posterior joint TMJ spaces were significantly increased from 2.49 ± 0.88 mm and 1.25 ± 0.79 mm to 2.98 ± 1.02 mm and 1.86 ± 0.72 mm, respectively. The value of the difference from the bilateral condyle head position to the X and Z axes significantly decreased from 2.50 ± 1.56 mm and 2.30 ± 1.57 mm to 1.64 ± 1.58 mm and 1.82 ± 1.11 mm, respectively. CONCLUSION: The main positional effect of the stabilization splint treatment in TMD patients with MD includes considerable correction of mandibular deviation, improving facial asymmetry, and moving the condyle into a stable condylar position; these were done by promoting the mandible to rotate around the Z (roll) and Y (yaw) axes and by forward, downward, and outward condylar movement on the deviated side, respectively.

The influence of nasal deviation on the perception of maxillary dental centreline and smile aesthetics.

OBJECTIVE: To assess the impact of nasal deviation on the perception of the maxillary dental centreline position as judged by orthodontists, dentists and laypersons. DESIGN: Cross-sectional study. SETTING: Barts and the London School of Medicine and Dentistry, Queen Mary University of London, UK. PARTICIPANTS: Three groups of raters comprising 30 orthodontists, 30 dentists and 30 laypersons. METHODS: A frontal photograph of a smiling white woman was captured and digitally manipulated with varying degrees of nasal deviation and dental centreline (DC) position in increments of 1.5 mm and 3 mm to the right and left. Three rater groups assessed the attractiveness of images using a visual analogue scale (VAS). Multiple regression analysis was undertaken, and images were compared using the Tukey HSD method. RESULTS: Using a mixed linear model, the intraclass correlation coefficient (ICC) was estimated in the range of 69%-86%, indicating good inter-rater reliability. The interaction between image rating and nasal position (P < 0.001), DC position (P < 0.001) and the relationship between nose and DC position (P < 0.001) were found to be statistically significant with symmetrical upper midline and nasal tip position, both considered to be most aesthetically pleasing. Image rating was not influenced by rater group type (P = 0.995), age (P = 0.983) or sex (P = 0.476). CONCLUSION: There was a preference for a central and coincident nose and maxillary DC position uniformly across the rater groups. Deviations of the nose, DC and their interactions negatively impacted on perceived smile aesthetics with increasing extent and opposing direction of deviations rated progressively more unaesthetic. No differences were observed between orthodontists, general dental practitioners and lay people with respect to perceived impact on smile aesthetics.

Comparison of tissue displacement in edentulous arches among three-dimensional files obtained through different impression-making methods: A retrospective study.

PURPOSE: To retrospectively compare and analyze differences in tissue displacement of edentulous arches among three-dimensional (3D) files obtained using various impression-making techniques. MATERIALS AND METHODS: Fourteen patients who underwent prosthodontic treatment for edentulous arches at Yonsei University Dental Hospital between June 2020 and April 2023 were included in the study. Three types of 3D files were used for the evaluation of each arch: a 3D scan file of a definitive cast (Group DEF), a preliminary cast (Group PRE), and an intraoral scan file (Group IOS). The files were superimposed on a reference 3D scan file of the definitive cast group through best-fit matching using metrology software. Seventeen measurement points (MP1-4, RC1-6, TB1-2, and PPS1-5 for the maxilla and RP1-2, RC1-7, BS1-4, and LS1-4 for the mandible) were selected for both the maxillary (n = 13) and mandibular arches (n = 6). The deviation considering the direction (DD) between the three groups and the absolute deviation (AD) between the three groups were recorded. Kruskal-Wallis and post-hoc Mann-Whitney tests were used for statistical analyses (α = 0.05 and α = 0.0167, respectively). RESULTS: Concerning the DD values, at the RC4 point of the maxillary arch, Group PRE exhibited significantly higher values than Groups IOS (p = 0.006) and DEF (p < 0.001), and at the RC5 point of the maxillary arch, Group IOS exhibited significantly lower values than Groups PRE (p = 0.016) and DEF (p < 0.001). Group IOS showed significantly lower DD values in the mandibular arch than Group DEF at the RP2 and RC3 points (p < 0.167). The AD values in Groups PRE and IOS significantly differed from those in Group DEF (all p < 0.001) at all measurement points but did not exhibit significant differences between each other (p > 0.05). CONCLUSIONS: Different impression-making methods yielded different amounts of tissue displacement. The tendency of 3D files regarding tissue displacement varied at certain residual ridge crest areas and retromolar pad areas. The absolute amount of tissue displacement observed in the intraoral scan data was comparable to that observed in the preliminary casts.

3D Surface Deviation Wear Analysis of Veneered PEEK Crowns and Its Correlation with Optical Digital Profilometry.

PURPOSE: To verify whether 3D surface deviation analysis software can detect the surface changes of composite veneered polyetheretherketone posterior crowns following wear simulation compared to optical digital profilometry. MATERIALS AND METHODS: Twenty dental crowns, fabricated from CAD-CAM polyetheretherketone (PEEK) and veneered with high impact polymer composite (HIPC), were subjected to wear test (50N, 5/55°C; 120,000 chewing cycles). Optical digital profilometry and 3D surface deviation using Geomagic design X software was used before and after the wear test to measure volumetric wear loss (mm3 ). The data were statistically analyzed with Wilcoxon signed-rank test to compare the two methodologies. The significance level was set at p ≤ 0.05. RESULTS: There was no statistically significant difference between the two assessment methods (p-value = 0.075, Effect size = 0.854). Regarding the optical digital profilometry analysis, HIPC veneered PEEK crowns showed 0.01686 (0.018-0.02155) mm3 as a median volumetric wear loss value. While the crowns analyzed by 3D surface deviation showed -0.0398 (-0.0913 to -0.0042) mm3 as a median volumetric loss value (p-value = 0.075, Effect size = 0.854). In addition, there was no statistically significant correlation between wear measurements by optical digital profilometry and 3D surface deviation analyses (ρ = -0.177, p-value = 0.685). CONCLUSIONS: There was no significant difference or correlation between optical digital profilometry and 3D surface deviation analyses for volumetric wear loss of veneered PEEK crowns.

Nasal patency and mandibular movement: clinical application in prosthodontics.

This case report describes a patient with a primary concern of persistent mandibular deviation during speech who experienced clinically significant improvement (mandibular movement without deviation) after improvements to nasal resistance. At the initial consultation, temporary placement of a nasal valve dilator immediately eliminated the patient's mandibular deviation during speech, indicating the need for referral to an otolaryngologist. The patient was also provided with a dental appliance to address secondary concerns of temporomandibular joint noises and cervicofacial pain. Although the dental treatment provided some relief, resolution of the patient's mandibular deviation during speech did not occur until after nasal surgery was completed. This case illustrates the importance and effects of nasal resistance and nasal patency to obtaining a reproducible mandibular position.

Accuracy of Static Computer- Assisted Implant Placement in Posterior Edentulous Areas with Different Levels of Tooth- Support by Novice Clinicians.

Correct implant placement is necessary for satisfactory implant restoration. Therefore, the use of surgical guide is recommended. This study evaluated the accuracy of implant placement in posterior edentulous areas with different levels of tooth-support by novice clinicians according to fully-guided (FG), pilot-guided (PG), and freehand (FH) placement protocols. A mandibular model with missing first molars was designed. On one side, the model had a bound edentulous area (BEA), and on the other side, a free end edentulous area (FEA). Fourteen clinicians new to implant dentistry participated in the study, and each clinician inserted an implant in the BEA and FEA sites for every placement protocol. Angle, vertical and maximum horizontal platform and apex deviations were measured. The FG placement was more accurate than the PG and FH placements. This was significant for BEA angle deviation, BEA and FEA maximum horizontal platform deviations, and BEA maximum horizontal apex deviation. The PG placement was significantly more accurate than the FH placement for BEA and FEA maximum horizontal platform deviations. FG shows significantly greater angle, maximum horizontal platform and maximum horizontal apex deviations at FEA than BEA. This can be attributed to reduced guide support and the possibility of guide displacement during surgery.

Beneficial effects of PEGylated graphene quantum dot on arrhythmias induced by myocardial infarction.

Arrhythmias are one of the leading causes of early death following myocardial infarction (MI) and heart failure. Graphene derivatives have emerged as an therapeutic target that have electrical conductivity. The study aimed to evaluate the impacts of polyethylene glycol-graphene quantum dots (GQDs-PEG) on arrhythmias created by MI in the rat. Animals were randomly assigned to five groups of sham, MI, and MI + GQDs-PEG at doses of 5, 10, and 20 mg/kg. MI was induced by the closure of the left anterior descending artery. The day after MI, animals were administered vehicle (phosphate buffered saline) or GQDs-PEG at different doses every other day for 2 weeks. On day 15, electrocardiogram (ECG), mean arterial pressure (MAP), and heart contractility indices were recorded by the PowerLab data acquisition system. GQDs-PEG 20 mg/kg increased contractility and improved the reduction of MAP in the MI group. The prolonged QT and QTc intervals, inverted T wave, and deviated ST segment were modified by GQDs-PEG 10 and 20 mg/kg in rats with MI. The amplitude of the Q wave was also decreased in a dose-dependent manner in the GQDs-PEG-treated rats. The results demonstrated that 2 weeks of treatment with GQDs-PEG normalized ECG abnormalities and improved left ventricular dysfunction in rats with MI.

Perception of the Nose and Lower Face Before and After Orthognathic Surgery in Subjects with Dento-maxillofacial Deformities: An Eye-Tracking Study.

BACKGROUND: Dento-maxillofacial deformities are often associated with nasal deviation, and patients often complain of nasal deviation after orthognathic surgery. This study aimed to quantitatively evaluate the facial visual attention given to dento-maxillofacial deformities accompanying nasal deviation from the perspective of patients and determine whether orthognathic surgery could alter this outcome. METHODS: The scanning paths of 137 patients were recorded using an eye-tracking device; recordings were made while the patients viewed images of dento-maxillofacial deformities associated with various degrees of nasal deviation before or after orthognathic surgery. Visual attention focused on the lower face and nose was analyzed. RESULTS: When viewing postoperative faces, the participants focused more visual attention on noses and less on the lower face than they did on preoperative faces. Interestingly, for preoperative faces, nasal deviation could significantly increase participants' visual attention to the lower face, and visual attention to noses was significantly increased when noses were deviated 12°, while for postoperative faces, a nasal deviation of 4° or more was associated with a significant increase in participants' visual attention to the nose. CONCLUSIONS: Patients tended to focus their visual attention on the lower region of preoperative faces and ignored nose irregularities. Orthognathic surgery can alter visual attention, shifting it from the lower face to the nose, and a deviation of 4° or more could be a potential concern for patients. Clinicians must inform patients preoperatively about preexisting nasal deviations, which can guide surgical planning and help manage patient expectations. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Evaluation of Maxillary Sinus Characteristics in Patients With Cleft Lip and Palate Using Cone Beam Computed Tomography.

OBJECTIVES: The detection of anatomical variation impairments in patients with cleft lip and palate (CLP) is crucial in combined orthodontic and maxillofacial surgical treatments. Therefore, this study aimed at evaluating the anatomical maxillary sinus characteristics, nasal septum deviation (NSD), and mucosal thickening of the maxillary sinus in patients with CLP using cone beam computed tomography (CBCT). DESIGN: The CBCT images were classified into 3 groups of unilateral cleft lip and palate (UCLP; n = 40), bilateral cleft lip and palate (BCLP; n=14), and noncleft (control; n = 54). Subsequently, the maxillary sinus linear dimensions were assessed. Height, width, depth, infundibulum height, and ostium width were assessed as quantitative measures, whereas nasal septum deviation and mucosal thickening were assessed as qualitative measures. One-way analysis of variance and χ2 tests were utilized to identify any significant differences among the groups regarding the aforementioned variables. RESULTS: Significant differences were observed among the groups regarding maxillary sinus height and depth, NSD, and mucosal thickening. Moreover, UCLP and BCLP groups showed higher incidence of NSD and mucosal thickening. However, the size of maxillary sinus height and depth was lower in the UCLP and BCLP groups. CONCLUSION: The results showed that BCLP and UCLP groups obtained lower maxillary sinus height and depth compared to the control group. On the other hand, incidence of the NSD and mucosal thickening was significantly higher in UCLP and BCLP groups than those in the control group.

Virtual surgical planning is a useful tool in the surgical management of mandibular condylar fractures.

PURPOSE: The aim of this study is to evaluate the application value of virtual surgical planning in the management of mandibular condylar fractures and to provide a reliable reference. METHODS: This was a prospective randomized controlled study and recruited 50 patients requiring surgical treatment for their mandibular condylar fractures. The inclusion criteria were patients (1) diagnosed with a condylar fracture by two clinically experienced doctors and required surgical treatment; (2) have given consent for the surgical treatment; and (3) had no contraindications to the surgery. Patients were excluded from this study if: (1) they were diagnosed with a non-dislocated or only slightly dislocated condylar fracture; (2) the comminuted condylar fracture was too severe to be treated with internal reduction and fixation; or (3) patients could not complete follow-up for 3 months. There were 33 male and 17 female patients with 33 unilateral condylar fractures and 17 bilateral condylar fractures included. The 50 patients were randomly (random number) divided into control group (25 patients with 35 sides of condylar fractures) and experimental group (25 patients with 32 sides of condylar fractures). Virtual surgical planning was used in the experimental group, but only clinical experience was used in the control group. The patients were followed up for 1, 3, 6 and 12 months after operation. Variables including the rate of perfect reduction by radiological analysis, the average distance of deviation between preoperative and postoperative CT measurements using Geomagic software and postoperative clinical examinations (e.g., mouth opening, occlusion) were investigated for outcome measurement. SPSS 19 was adopted for data analysis. RESULTS: The average operation time was 180.60 min in the experimental group and 223.2 min in the control group. One week postoperatively, CT images showed that the anatomic reduction rate was 90.63% (29/32) in the experimental group and 68.57% (24/35) in the control group, revealing significant difference (X2 = 4.919, p = 0.027). Geomagic comparative analysis revealed that the average distance of deviation was also much smaller in the experimental group than that in the control group (0.639 mm vs. 0.995 mm; t = 3.824, p < 0.001). CONCLUSION: These findings suggest that virtual surgical planning can assist surgeons in surgical procedures, reduce operative time, and improve the anatomic reduction rate & accuracy, and thus of value in the diagnosis and treatment of condylar fractures.

Effect of septal deviation on nasomaxillary shape: A geometric morphometric study.

Nasal cavities in their primitive stage communicate with the oral cavity until the 8th week of intrauterine life where the posterior palate initiates its development. Hence, starting from the initial growth phases, a significant connection lays between the nasal structures and the maxillary bone and witnessing key functional roles, among which the respiration. Proper nasal breathing has been proven to be a crucial factor for the maturity of the craniofacial complex, and obstruction of the respiratory airway due to nasal septum deviation can generate clinically significant reduction of the nasal airflow. This situation will imply irreversible repercussions that hinders the harmonious development of the craniofacial complex. In order to understand such potential impacts of septal deviation, our first objective was to materialize the relation between septum deviation, and both nasal cavity and maxillary structures. For the second objective, we used Procrustes analysis to assess the shape variation of these two anatomical regions, the bivariate plots of Principal Components to evaluate their shape space, and a two-block Partial Least Square (PLS) to explore their covariation. We analysed, in this cross-sectional study, 62 posteroanterior cephalometric radiographs of adult subjects from both sexes (23 males, 39 females; mean age 25.3 years) collected from the database of the Department of Orthodontics at Lebanese University. Landmarks were plotted and variables were calculated and divided into nasal septum, nasal cavity and maxillary ones. The sample was further divided into two groups based on septal deviation severity (a septal deviation is considered minor if <6). The results suggested that nasal septum deviation was correlated to reduced nasal cavity area and a reduced maxillary area. Moreover, the comparison of the two groups concluded that the difference between all variables was statistically significant with higher scores in the minor septal deviation group. These findings were corroborated with the shape analysis where the mean centroid size of nasal cavity and that of the maxilla in the group of reduced septal deviation were significantly greater than those of the group with increased angle of deviation. Results of PLS analysis concluded to a strong covariation between nasal septum and nasomaxillary complex. These conclusions support the early septoplasty in growing patients as a solution to redirect the normal course of growth and re-establish a good function of the nasomaxillary complex.