Are There Differences in the Causes and Complications of Mandibular Third Molar Extraction in Older Patients Compared to Younger Patients?

BACKGROUND: Although most impacted third molars (ITMs) are extracted in the teens and early 20s, some undergo extractions after their 40s. It is unclear whether the reasons for extraction, the degree of impaction, and complications differ in patients in an older age group compared with a younger age group. PURPOSE: The purpose of this study was to measure the association between age and 1) reason for extraction and 2) postoperative complications. STUDY DESIGN, SETTING, SAMPLE: This was a retrospective cohort study of patients who had undergone surgical extraction of at least one mandibular ITM at a single institution. We excluded 1) age under 20 years, 2) follow-up period of less than 1 week, and 3) tooth extraction under general anesthesia. PREDICTOR VARIABLE: The primary predictor variable was age, classified into 3 groups (20s:20-29; 30s:30-39; over 40s: 40 and greater). MAIN OUTCOME VARIABLE(S): The primary outcome variables were the reason for extraction (prophylactic or symptomatic) and the presence of complications. The secondary outcome variable was type of complication (postoperative infection, dry socket, neurosensory disturbance, presenting pain over 1 month, retained root requiring secondary treatment). COVARIATES: The covariates were sex, laterality of ITM, and difficulty of extraction as measured by the difficulty index, a measure based on depth, orientation, and ramus relationship/space available, with a higher score indicating greater difficulty. ANALYSES: χ2 test was performed to analyze the association of categorical outcome variables and covariates. Level of statistical significance was set at P < .05. RESULTS: Of a total of 831 eligible subjects, there were 555 (66.8%), 159 (19.1%), and 117 (14.1%) in the 20s, 30s, and over 40s age groups, respectively. The percentage of symptomatic extraction of ITM was significantly higher in the over-40 age group compared with the 20s group (92.3 vs 69.4%, (P < .001). Complication rate also significantly differed between over 40s group and the 20s group (7.7 vs 1.8%, P < .001). Difficulty index and indications for ITM extraction were significantly different between groups (P < .001). CONCLUSION AND RELEVANCE: Symptoms, difficulty, and complications related to ITM increase at over 40 years of age. This should be taken into consideration during the joint clinical decision-making process with patients with ITM.

Effect of orbital volume in unilateral orbital fracture on indirect traumatic optic neuropathy.

PURPOSE: This retrospective study aimed to analyze the relationship between the volume of the fractured and the normal orbit in patients with unilateral orbital fractures with and without indirect traumatic optic neuropathy (TON). SUBJECTS: Data of 25 patients with unilateral orbital fractures who underwent computer tomography between January 2016 and December 2020 were investigated. Emergency imaging was performed within 2 hours of arrival at the emergency room. The subjects were categorized into two groups: unilateral orbital fractures with and without TON. METHODS AND MEASURES: The assessment of TON was performed during a comprehensive ophthalmologic examination by an ophthalmologist. The stereographic orbit was reconstructed, and the volume was calculated. Other variables examined included age, sex, and cause of orbital trauma. The variables were compared using paired t-tests. Statistical significance was set at p < 0.05. RESULTS: The orbital volume of the non-fractured orbit was 27.50 ± 2.26 and 27.48 ± 2.64 cm3 in the groups with and without TON, respectively. The average volume of the fractured orbit in the TON group was 27.78 ± 2.56 cm3, and there was no significant volumetric difference between the fractured and non-fractured sides in this group. However, the average volume of the fractured orbit without TON was 28.76 ± 3.18 cm3, larger than that of the non-fractured orbit (p = 0.016). CONCLUSIONS: Non-expansion of the fractured orbit was a risk factor for indirect TON in patients with unilateral orbital fractures. Volumetric analysis from primary imaging would expedite the diagnosis and treatment of TON, resulting in optimal outcomes.

What Is the Perception of an Esthetic Lower Facial Third Profile in the Korean Layperson Population?

PURPOSE: The purpose of this study is to investigate whether there were differences in perception of facial profile esthetics at the upper lip, gnathic, and genial levels according to observer gender and age in the Korean layperson population. METHODS: Ten male (M1 to M10) and 10 female (F1 to F10) silhouettes with differing facial profiles at the level of the upper lip, mandibular, and chin were created from a male and female facial profile deemed well-balanced and orthognathic by reviewer consensus. These silhouettes were presented to 288 participants who were asked to rank the 5 most attractive male and female profiles. The participants were composed of 144 males and 144 females divided into 4 age groups: group I (under 20 years), group II (20 to 39 years), group III (40 to 59 years), and group IV (over 60 years). The most preferred profile and observer scores were investigated and calculated. Descriptive analysis, χ2 test, and analysis of variance were used for statistical analysis according to age and gender. RESULTS: The most preferred male and female silhouettes were orthognathic profiles. There was no significant difference according to gender when rating male (P = .281) and female (P = .442) silhouettes. No statistically significant difference was observed even when analyzed according to age groups. Although the difference in observer scores among each ranking showed a statistical difference according to age groups, the overall rankings showed a similar pattern both in male and female silhouettes. In the same age group, no difference in rank scores according to gender was observed. Severe concave profiles were found to have the lowest rank. CONCLUSIONS: An orthognathic profile was rated as the most desirable in the Korean layperson population, with few differences in perception of esthetic facial profile according to age and gender.

Follow-up evaluation of temporomandibular joints using magnetic resonance imaging after mandibular trauma: Case series analysis of young adult males.

BACKGROUND/AIMS: A relationship between mandibular fractures and traumatic temporomandibular joint (TMJ) conditions has been suggested in many studies. Although magnetic resonance imaging (MRI) is the best option for a TMJ evaluation, few studies have evaluated the TMJ condition after a mandibular fracture using MRI follow-up. The aim of this study was to evaluate the TMJ for post-traumatic conditions following a mandibular fracture using follow-up MRI. MATERIALS AND METHODS: Fourteen TMJs of seven young adult males (aged 19-21 years) with mandibular fractures were analyzed by MRI, and 12 TMJs of six patients were evaluated by follow-up MRI after the trauma. Regarding the intensity of MRI, the pathologic condition of TMJ was classified into acute joint inflammation, marrow edema, and joint space widening. RESULTS: Thirteen joints (92.9%) showed pathologic conditions, including 11 with acute joint inflammation (84.6%), 10 with joint space widening (76.9%), and six with marrow edema (46.2%). Five out of 12 evaluated joints were injected with dexamethasone. Among these, four joints healed within one week, and one healed within one month. Among the seven untreated TMJs, four and one joint healed within one week and one month, respectively, but two joints of one patient did not improve until one month. Although that patient received arthrocentesis, the right joint showed osteoarthritis six months after the trauma. CONCLUSIONS: Most TMJs were acutely damaged due to mandibular trauma and healed within one week to one month. A follow-up examination could be considered at one month after the injury to confirm the possibility of traumatic TMJ disorder, such as osteoarthritis.

Craniofacial and dental injuries associated with stand-up electric scooters.

BACKGROUND/AIM: With the recent increased share of stand-up electric scooters (e-scooters), it is common to see people riding e-scooters on the roads in Korea. The aim of this study was to investigate traumatic injuries to the craniofacial region related to e-scooter accidents and to determine the role of dentists (especially oral and maxillofacial surgeons) in the evaluation of patients with trauma at the emergency department due to an e-scooter accident. MATERIALS AND METHODS: This retrospective study investigated the medical records of patients who visited the Gangnam Severance Hospital Emergency Care Center for trauma related to e-scooter use from January 1, 2017 to March 31, 2020. Medical records were reviewed to determine the injuries sustained to the craniofacial region related to e-scooter use, including location of the injury (eg, cranium, craniofacial bone, teeth, soft tissue) and the type of trauma (eg, fracture, laceration, abrasion, contusion, concussion). RESULT: A total of 256 patients' medical records were evaluated. Among them, 125 patients (48.8% of all patients) had sustained craniofacial trauma. Laceration (n = 56, 44.8%) was the most common type of craniofacial injury, followed by cerebral concussion (n = 49, 39.2%), dental injury (n = 27, 21.6%), and craniofacial bone fracture (n = 16, 12.8%). CONCLUSION: Dentists should always consider the possibility of brain trauma and perform a complete craniofacial and oral examination when assessing patients after e-scooter accidents as outlined by the International Association of Dental Traumatology guidelines. Additionally, it is necessary to educate e-scooter riders about the importance of wearing protective devices, such as helmets, to reduce the risk of injuries to the craniofacial region.

Three-dimensional assessment of the anterior and inferior loop of the inferior alveolar nerve using computed tomography images in patients with and without mandibular asymmetry.

BACKGROUND: The purpose of this study was to investigate the differences in configuration and dimensions of the anterior loop of the inferior alveolar nerve (ALIAN) in patients with and without mandibular asymmetry. METHOD: Preoperative computed tomography images of patients who had undergone orthognathic surgery from January 2016 to December 2018 at a single institution were analyzed. Subjects were classified into two groups as "Asymmetry group" and "Symmetry group". The distance from the most anterior and most inferior points of the ALIAN (IANant and IANinf) to the vertical and horizontal reference planes were measured (dAnt and dInf). The distance from IANant and IANinf to the mental foramen were also calculated (dAnt_MF and dInf_MF). The length of the mandibular body and symphysis area were measured. All measurements were analyzed using 3D analysis software. RESULTS: There were 57 total eligible subjects. In the Asymmetry group, dAnt and dAnt_MF on the non-deviated side were significantly longer than the deviated side (p < 0.001). dInf_MF on the non-deviated side was also significantly longer than the deviated side (p = 0.001). Mandibular body length was significantly longer on the non-deviated side (p < 0.001). There was no significant difference in length in the symphysis area (p = 0.623). In the Symmetry group, there was no difference between the left and right sides for all variables. CONCLUSION: In asymmetric patients, there is a difference tendency in the ALIAN between the deviated and non-deviated sides. In patients with mandibular asymmetry, this should be considered during surgery in the anterior mandible.

Is There a Difference in Condyle Position Changing Pattern Between Deviated and Non-Deviated Sides After Intraoral Vertical Ramus Osteotomy in Facial Asymmetry?

PURPOSE: The position changing pattern of the condyles after intraoral vertical ramus osteotomy (IVRO) on the deviated and non-deviated sides is not clearly known. This study was conducted to evaluate the changes in condylar position after IVRO in patients with facial asymmetry and to compare the deviated and non-deviated sides using computed tomography imaging. MATERIALS AND METHODS: This retrospective cohort study investigated patients with a diagnosis of mandibular prognathism with facial asymmetry who had undergone bilateral IVRO with Le Fort I osteotomy. Condylar positions were recorded on the non-deviated and deviated sides in the midaxial, midsagittal, and coronal planes at 3 time points using 3-dimensional analysis software: preoperatively (T1), at 6 months postoperatively (T2), and at 12 months postoperatively (T3). Linear and angular changes in condyle position were measured and analyzed between T1, T2, and T3. Reliability and comparative analyses were conducted. RESULTS: Thirty-two patients were involved in this study. At T2, the most superior point of the condyle moved to 1.15 ± 0.24 mm (inferiorly) and 0.88 ± 0.23 mm (anteriorly) on the deviated side (P = .0002 and P = .0005, respectively) and to 0.99 ± 0.25 mm (inferiorly) and 1.08 ± 0.34 mm (anteriorly) on the non-deviated side, showing significant differences (P < .0001 and P = .0007, respectively) compared with T1. The condyle position showed a tendency to recover to its original position by T3. However, there were no statistically significant differences between T2 and T3 (P > .05). Furthermore, there were no statistically significant differences between the deviated and non-deviated sides over the entire follow-up period (P > .05). CONCLUSIONS: The condyles did not completely recover to their preoperative positions until 12 months postoperatively. There was no significant difference between the deviated and non-deviated sides in mandibular prognathism with facial asymmetry.

Clinical and microbiologic investigation of an expedited peri-implantitis dog model: an animal study.

BACKGROUND: Animal studies are pivotal in allowing experimentation to identify efficacious treatment protocols for resolution of peri-implantitis. The purpose of this investigation was to characterize an expedited dog peri-implantitis model clinically, radiographically, and microbiologically. METHODS: Eight hound dogs underwent extractions (week 0) and implant (3.3 × 8.5 mm) placement with simultaneous surgical defect creation and ligature placement for induction of peri-implantitis (week 10). Ligatures were replaced at 6 weeks (week 16) and removed after 9 weeks (week 19) when supporting bone loss involved approximately 50% of the peri-implant bone. Microbial samples from the defects and healthy control implant sites collected at week 19 were analyzed utilizing a microarray. Clinical measures of inflammation were obtained and radiographic bone loss was measured from periapical radiographs. Radiographic depth and width measurements of bony defect were repeated at weeks 10 (baseline), 16, and 19. Canonical analysis of principal coordinates was used to visualize overall differences in microbial abundance between peri-implantitis and healthy implants. RESULTS: This accelerated disease protocol led to intrabony defect creation with a mean depth and width of 4.3 mm and 3.5 mm, respectively after 9 weeks of ligature placement. Microbial identification revealed 59 total bacteria in peri-implant sites, 21 of which were only present in peri-implant sites as compared to healthy controls. Overall microbial beta diversity (microbial between-sample compositional diversity) differed between peri-implantitis and healthy implants (p = 0.009). CONCLUSIONS: Within the limitations of this study, this protocol led to expedited generation of peri-implant defects with a microbial profile indicative of a shift to disease and defect patterns conducive to regenerative treatment. However, the possibility of potential spontaneous resolution of lesions due to the lack of a chronicity interval as compared to chronic disease models need to be further clarified and considered during preclinical peri-implantitis model selection.

Effects of thread size in the implant neck area on peri-implant hard and soft tissues: an animal study.

OBJECTIVES: The aim of this animal study was to examine the effects of thread size in the implant neck area on peri-implant tissues in terms of BIC and hard- and soft-tissue dimensions. MATERIALS AND METHODS: Six Beagle dogs received experimental implants in the mandible 3 month after the removal of premolars and first molars (P2, P3, P4, and M1). Two different types of implants were installed in each animal: Anyone microthread(®) as Group 1 and Anyone(®) as Group 2. Resonance frequency test, intraoral radiography, micro-CT, and histomorphometry were used to evaluate peri-implant tissue after implantation periods of 4 and 8 weeks. RESULTS: No remarkable complication was observed during the healing period in either group. Resonance frequency testing revealed no significant difference between groups. In radiographic evaluation, Group 2 showed more bone loss than Group 1. However, this difference was not statistically significant. In the micro-CT analysis, BIC and BIV values and soft-tissue height were not significant in both groups. Histological analysis revealed no significant difference in BIC ratio, bone density, or bone loss between groups. However, soft-tissue height was significantly greater in Group 2 than in Group 1 (P = 0.0004). CONCLUSION: No difference in peri-implant hard or soft tissues was observed according to thread size in the implant neck area.

Rescue therapy with orthodontic traction to manage severely impacted mandibular second molars and to restore an alveolar bone defect.

This case report describes the successful treatment of severely impacted mandibular second molars with severe apical root resorption of the mandibular first molars. The vertically impacted second molars were orthodontically moved (using orthodontic mini-implants) without additional root resorption of the first molars. The orthodontic treatment provided a satisfactory and stable outcome by improving the periodontium surrounding the first and second molars. The treatment also eliminated the need for prosthetic treatment by preserving the first and second molars.

Chondroblastoma of the temporomandibular joint lateral capsule: a case report.

AIM: Chondroblastoma is a rare, benign bone tumor that accounts for approximately 1% of all primary bone tumors. Chondroblastoma that occurs at the temporomandibular joint can exhibit symptoms similar to those associated with other temporomandibular disorders. This case study aims to present an eight-year followup of chondroblastoma occurring at the temporomandibular joint. METHODOLOGY: The patient presented swelling in the left temporomandibular joint and trismus. Based oncomputed tomography and magnetic resonance imaging findings, a provisional diagnosis of synovial chondromatosis was made. Complete excision of the lesion was performed under general anesthesia. RESULTS: After histopathological examination, the lesion was finally diagnosed as chondroblastoma. Currently, 8 years after the operation, the patient has not experienced any symptoms or any notable complications. CONCLUSIONS: Although chondroblastoma is a benign tumor, it shows aggressive characteristics with bone invasion. Therefore, precise diagnosis and proper treatment planning is crucial for successful treatment of chondroblastoma.

Multi-class segmentation of temporomandibular joint using ensemble deep learning.

Temporomandibular joint disorders are prevalent causes of orofacial discomfort. Diagnosis predominantly relies on assessing the configuration and positions of temporomandibular joint components in magnetic resonance images. The complex anatomy of the temporomandibular joint, coupled with the variability in magnetic resonance image quality, often hinders an accurate diagnosis. To surmount this challenge, we developed deep learning models tailored to the automatic segmentation of temporomandibular joint components, including the temporal bone, disc, and condyle. These models underwent rigorous training and validation utilizing a dataset of 3693 magnetic resonance images from 542 patients. Upon evaluation, our ensemble model, which combines five individual models, yielded average Dice similarity coefficients of 0.867, 0.733, 0.904, and 0.952 for the temporal bone, disc, condyle, and background class during internal testing. In the external validation, the average Dice similarity coefficients values for the temporal bone, disc, condyle, and background were 0.720, 0.604, 0.800, and 0.869, respectively. When applied in a clinical setting, these artificial intelligence-augmented tools enhanced the diagnostic accuracy of physicians, especially when discerning between temporomandibular joint anterior disc displacement and osteoarthritis. In essence, automated temporomandibular joint segmentation by our deep learning approach, stands as a promising aid in refining temporomandibular joint disorders diagnosis and treatment strategies.

Volumetric changes in temporomandibular joint space following trans-oral vertical ramus osteotomy in patients with mandibular prognathism: a one-year follow-up study.

This study measured and analyzed chronological changes in temporomandibular joint space volume by compartment following transoral vertical ramus osteotomy (TOVRO) using reconstructed 3-dimensional (3D) images of patients with mandibular prognathism. It included 70 joints of 35 patients who underwent TOVRO between January 2018 and December 2021. Computed tomography (CT) or cone-beam CT (CBCT) was performed before surgery (T0) and at 3 days (T1), 6 months (T2), and 12 months postoperatively (T3). These scans were then analyzed using 3D software. The volumes of the overall (Vjs), anterior (Vajs), posterior (Vpjs), medial (Vmjs), and lateral (Vljs) joint spaces were calculated at each time point. A linear mixed model and repeated-measures covariance pattern with unstructured covariance were used to evaluate significant changes in joint space volume over time. Vjs significantly increased to 134.54 ± 34.28 mm3 at T3 compared to T0 (p < 0.001). Vpjas and Vljs increased by 130.72 ± 10.07 mm3 and 109.98 ± 7.52 mm3 at T3 compared to T0, respectively (p < 0.001). However, no significant difference was observed between T0 and T2 in Vajs and Vmjs (p = 0.9999). The observed volume increases in Vpjs and Vljs appeared to contribute to the overall Vjs increase.

Automated deep learning for classification of dental implant radiographs using a large multi-center dataset.

This study aimed to evaluate the accuracy of automated deep learning (DL) algorithm for identifying and classifying various types of dental implant systems (DIS) using a large-scale multicenter dataset. Dental implant radiographs of pos-implant surgery were collected from five college dental hospitals and 10 private dental clinics, and validated by the National Information Society Agency and the Korean Academy of Oral and Maxillofacial Implantology. The dataset contained a total of 156,965 panoramic and periapical radiographic images and comprised 10 manufacturers and 27 different types of DIS. The accuracy, precision, recall, F1 score, and confusion matrix were calculated to evaluate the classification performance of the automated DL algorithm. The performance metrics of the automated DL based on accuracy, precision, recall, and F1 score for 116,756 panoramic and 40,209 periapical radiographic images were 88.53%, 85.70%, 82.30%, and 84.00%, respectively. Using only panoramic images, the DL algorithm achieved 87.89% accuracy, 85.20% precision, 81.10% recall, and 83.10% F1 score, whereas the corresponding values using only periapical images achieved 86.87% accuracy, 84.40% precision, 81.70% recall, and 83.00% F1 score, respectively. Within the study limitations, automated DL shows a reliable classification accuracy based on large-scale and comprehensive datasets. Moreover, we observed no statistically significant difference in accuracy performance between the panoramic and periapical images. The clinical feasibility of the automated DL algorithm requires further confirmation using additional clinical datasets.

Buccal nerve schwannoma mimicking a salivary gland tumor: a rare case report.

Schwannomas are benign tumors originating from myelinating cells constituting nerve sheaths but rarely contain cellular elements of the nerve. The authors encountered a 47-year-old female patient with a schwannoma on the anterior mandibular ramus arising from the buccal nerve, measuring 3 cm×4 cm. Surgical resection was performed with preservation of the buccal nerve via microsurgical dissection. After one month, the sensory function of the buccal nerve was recovered without complications.

Effect of a vertical incision on postoperative swelling after an impacted mandibular third molar extraction: two cases with split-mouth designed magnetic resonance imaging analysis.

This study examined the effects of a vertical incision on postoperative edema after third molar extraction. The study design was that of a comparative split-mouth approach. Evaluation was performed via magnetic resonance imaging (MRI). Two patients with homogeneous bilateral impacted mandibular third molars were enrolled. These patients underwent facial MRI within 24 hours after simultaneous extraction surgery. Modified triangular flap and enveloped flap incisions were made. Postoperative edema was evaluated by MRI and was assessed according to anatomical space. The two pairs of homogeneous extractions demonstrated that vertical incisions were associated qualitatively and quantitatively with extensive postoperative edema. The edema associated with these incisions spread toward the buccal space, beyond the buccinator muscle. In conclusion, a vertical incision with mandibular third molar extraction was related to edema in the buccal space and the fascial space, which contributed to clinical facial swelling.

Explainable deep learning-based clinical decision support engine for MRI-based automated diagnosis of temporomandibular joint anterior disk displacement.

BACKGROUND AND OBJECTIVE: MRI is considered the gold standard for diagnosing anterior disc displacement (ADD), the most common temporomandibular joint (TMJ) disorder. However, even highly trained clinicians find it difficult to integrate the dynamic nature of MRI with the complicated anatomical features of the TMJ. As the first validated study for MRI-based automatic TMJ ADD diagnosis, we propose a clinical decision support engine that diagnoses TMJ ADD using MR images and provides heat maps as the visualized rationale of diagnostic predictions using explainable artificial intelligence. METHODS: The engine builds on two deep learning models. The first deep learning model detects a region of interest (ROI) containing three TMJ components (i.e., temporal bone, disc, and condyle) in the entire sagittal MR image. The second deep learning model classifies TMJ ADD into three classes (i.e., normal, ADD without reduction, and ADD with reduction) within the detected ROI. In this retrospective study, the models were developed and tested on the dataset acquired between April 2005 to April 2020. The additional independent dataset acquired at a different hospital between January 2016 to February 2019 was used for the external test of the classification model. Detection performance was assessed by mean average precision (mAP). Classification performance was assessed by the area under the receiver operating characteristic (AUROC), sensitivity, specificity, and Youden's index. 95% confidence intervals were calculated via non-parametric bootstrap to assess the statistical significance of model performances. RESULTS: The ROI detection model achieved mAP of 0.819 at 0.75 intersection over union (IoU) thresholds in the internal test. In internal and external tests, the ADD classification model achieved AUROC values of 0.985 and 0.960, sensitivities of 0.950 and 0.926, and specificities of 0.919 and 0.892, respectively. CONCLUSIONS: The proposed explainable deep learning-based engine provides clinicians with the predictive result and its visualized rationale. The clinicians can make the final diagnosis by integrating primary diagnostic prediction obtained from the proposed engine with the patient's clinical examination findings.

Micellized protein transduction domain-bone morphogenetic protein-2 accelerates bone healing in a rat tibial distraction osteogenesis model.

The clinical application of growth factors such as recombinant human bone morphogenetic protein-2 (rh-BMP-2), for functional bone regeneration remains challenging due to limited in vivo efficacy and adverse effects of previous modalities. To overcome the instability and short half-life of rh-BMP-2 in vivo, we developed a novel osteogenic supplement by fusing a protein transduction domain (PTD) with BMP-2, effectively creating a prodrug of BMP-2. In this study, we first created an improved PTD-BMP-2 formulation using lipid nanoparticle (LNP) micellization, resulting in downsizing from micrometer to nanometer scale and achieving a more even distribution. The micellized PTD-BMP-2 (mPTD-BMP-2) demonstrated improved distribution and aggregation profiles. As a prodrug of BMP-2, mPTD-BMP-2 successfully activated Smad1/5/8 and induced mineralization with osteogenic gene induction in vitro. In vivo pharmacokinetic analysis revealed that mPTD-BMP-2 had a much more stable pharmacokinetic profile than rh-BMP-2, with a 7.5-fold longer half-life. The in vivo BMP-responsive element (BRE) reporter system was also successfully activated by mPTD-BMP-2. In the in vivo rat tibia distraction osteogenesis (DO) model, micro-computed tomography (micro-CT) scan findings indicated that mPTD-BMP-2 significantly increased bone volume, bone surface, axis moment of inertia (MOI), and polar MOI. Furthermore, it increased the expression of osteogenesis-related genes, and induced bone maturation histologically. Based on these findings, mPTD-BMP-2 could be a promising candidate for the next-generation osteogenesis drug to promote new bone formation in DO surgery. STATEMENT OF SIGNIFICANCE: This study introduces micellized bone morphogenetic protein-2 (mPTD-BMP-2), a next-generation osteogenic supplement that combines protein transduction domain (PTD) and nano-sized micelle formulation technique to improve transduction efficiency and stability. The use of PTD represents a novel approach, and our results demonstrate the superiority of mPTD-BMP-2 over rh-BMP-2 in terms of in vivo pharmacokinetic profile and osteogenic potential, particularly in a rat tibial model of distraction osteogenesis. These findings have significant scientific impact and potential clinical applications in the treatment of bone defects that require distraction osteogenesis. By advancing the field of osteogenic supplements, our study has the potential to contribute to the development of more effective treatments for musculoskeletal disorders.

Sensory change after implant surgery: related factors for recovery.

Objectives: This retrospective study aimed to analyze data on nerve damage in patients who complained of sensory changes after dental implant surgery, the clinical results according to proximity of the implant fixture to the inferior alveolar nerve (IAN) canal, and the factors affecting recovery of sensation. Materials and Methods: The electronic medical records of 64 patients who had experienced sensory change after implant surgery were reviewed. Patients were classified by sex, age, implant installation sites, recovery rate and the distance between the implant fixture and IAN canal on computed tomography (CT). The distance was classified into Group I (D>2 mm), Group II (2 mm≥D>0 mm), and Group III (D≤0 mm). Results: The 64 patients were included and the mean age was 57.3±7.3 years. Among the 36 patients who visited our clinic more than two times, 21 patients (58.3%) reported improvement in sensation, 13 patients (36.1%) had no change in sensation, and 2 patients (5.6%) reported worsening sensation. In Group II, symptom improvement was achieved in all patients regardless of the removal of the implant fixture. In Group III, 8 patients (40.0%) had reported symptom improvement with removal of the implant fixture, and 2 patients (33.3%) of recovered patients showed improvement without removal. Removal of the implant fixture in Group III did not result in any significant difference in recovery (P=0.337), although there was a higher possibility of improvement in sensation in removal cases. Conclusion: Clinicians first should consider removing the fixture when it directly invades the IAN canal. However, in cases of sensory change after dental implant surgery where the drill or implant fixture did not invade the IAN canal, other indirect factors such as flap elevation and damage due to anesthesia should be considered as causes of sensory change. Removal of the implant should be considered with caution in these situations.

Needle orientation for temporomandibular joint arthrocentesis in Koreans.

OBJECTIVE: To investigate the highest opportunity skin puncture point and needle orientation according to facial asymmetry and classification. METHODS: Computed tomography of 136 patients was analyzed. Horizontal and vertical angles and distances from the canthal-tragal line were investigated to determine the puncture point and needle's angle. RESULT: All patients' average points were 7.39 (±2.85) mm anterior to the tragus and 3.44 (±4.18) mm below the canthal-tragal line with an angle of 8.53 (±6.90)° anteriorly and 32.26 (±7.23)° superiorly. Regarding asymmetry, there was a statistical difference in horizontal angle, depth, and canthal-tragal distance between the deviated and non-deviated sides. Especially, vertical distances were 4.44 (±4.66) mm and 2.59 (±4.11) mm in the deviated and non-deviated sides, respectively (p < 0.001). CONCLUSION: In closed-mouth, the puncture point was closer to the tragus and lower than the conventional point. The point in the deviated side should be considered lower than the non-deviated side.