Morphologic Changes of the Temporomandibular Joint in Pruzansky-Kaban Type IIa Hemifacial Microsomia Postmandibular Distraction Osteogenesis.

OBJECTIVE: Mandibular distraction osteogenesis (MDO) is a powerful tool for the correction of hemifacial microsomia (HFM). The temporomandibular joint (TMJ) is the focus of attention in the diagnosis and treatment of HFM. This observational retrospective cross-sectional study aimed to investigate morphologic changes in TMJ post-MDO in type IIa HFM. METHODS: We recruited 48 patients with unilateral type IIa HFM who had completed MDO and mandibular distractor extraction (MDE). Data relating to the length, distance, angle, and volume of the TMJ were measured on 3-dimension models created by the analysis of computed tomography data. Normality analysis was performed by using the Shapiro-Wilk test. Data were compared with the paired t test and Wilcoxon signed-ranks test. RESULTS: The spaces between the affected condyle and the affected glenoid fossa before MDO were all significantly larger than before MDE (P<0.05). The breadth of the affected glenoid fossa before MDO was significantly longer than before MDE (P<0.001). The height of the affected condyle before MDO was significantly longer than before MDE (P<0.001). The volume of the affected condyle before MDO was significantly larger than before MDE (P<0.001). The ratio between the volume of the affected condyle and unaffected condyle before MDO was 0.20±0.13. The ratio between the volume of the affected condyle before MDE and MDO was 0.65±0.32. The resorption rate of the affected condyle post-MDO was 0.35±0.32. CONCLUSION: Herein, we characterized anatomic changes of the TMJ in type- IIa HFM post-MDO. Condylar resorption and the compression of space between the condyle and the glenoid fossa on the affected side were 2 typical manifestations. Our findings enhanced the understanding of the application of MDO on HFM.

Three-Dimensional Measurement of the Temporomandibular Joint in Pruzansky-Kaban Type IIa Hemifacial Microsomia.

OBJECTIVE: This observational retrospective cross-sectional study aimed to investigate the morphological characteristics of the temporomandibular joint (TMJ) in type IIa hemifacial microsomia (HFM). METHODS: We recruited 88 patients with unilateral type IIa HFM. Data relating to the length, distance, and angle of the TMJ, were measured on 3-dimensional models created by the analysis of computed tomography data. Normality analysis was performed by using the Shapiro-Wilk test. Data were compared with the paired t test and Wilcoxon signed-rank test. RESULTS: The height, long axis, and short axis of the affected condyle were significantly shorter than the unaffected side ( P <0.001); the ratios were 0.41±0.15, 0.75±0.20, and 0.95±0.24, respectively. The spaces between the condyle and the glenoid fossa were significantly larger in affected TMJs ( P <0.001). The ratio between the ipsilateral and contralateral anterior space in the sagittal plane was 4.62±2.59; this was significantly different than the ratio of inner space (1.50±1.70), superior space (1.70±0.97), and lateral space (1.28±0.62) in the coronal plane ( P <0.001) and the ratio of superior space (1.43±1.05) and posterior space (1.47±0.98) in the sagittal plane ( P <0.001); there were no statistical differences between the 5 spaces ( P >0.05). The breadth and depth of the glenoid fossa were significantly shorter in affected TMJs ( P <0.001), the ratio of the breadth in the affected and unaffected glenoid fossa was between 0.5 and 1 and the depth of the affected glenoid fossa was almost half of that on the unaffected side. The ratio between the ipsilateral and contralateral height of the condyle was significantly different when compared with the length of the mandibular ramus ( P <0.001). The ratio between the ipsilateral height of the condyle and the length of the mandibular ramus was significantly different when compared with that of the contralateral side ( P <0.001). The height of the affected condyle were significantly different ( P =0.005) among different ages. CONCLUSIONS: We found that hypoplasia was more severe in terms of the height of the condyle than the long axis and short axis of the condyle. The degree of condyle deformity was more severe than the mandible. And the affected condyle still had growth potential in the vertical direction with age.

Mandibular Distraction Osteogenesis First for Children With Severe Unilateral Hemifacial Microsomia: Treatment Strategy and Outcomes.

ABSTRACT: The treatment for severe hemifacial microsomia (HFM), especially type III case, is extremely difficult. Mandibular distraction osteogenesis (MDO) was rarely used as the primary choice in the treatment of severe type cases. The authors sought to observe the short-term therapeutic outcomes of patients with severe unilateral HFM who underwent MDO first.A retrospective study of children underwent MDO or later received costochondral graft (CCG) for severe unilateral HFM from 2009 to 2019 was conducted. Cephalometric measurements and clinical variables were analyzed to evaluate the effectiveness of MDO first strategy for severe cases and compare disparity between Pruzansky-Kaban classification type IIb and type III groups.Thirty-six patients (23 males and 13 females) underwent MDO first for severe HFM were included for analysis in the present study. The average age at MDO was 8.33 ±â€Š2.03 years. At the last follow-up, MDO acquired significant improvement in mandibular height, maxillary cant, chin deviation, lip commissural line tilt, and clinical chin deviation (P < 0.05). Distraction results were stable during the short-term follow-up in terms of the mandibular height ratio and maxillary cant (P > 0.05).MDO is a proper primary method for suitable type IIb and type III HFM cases. MDO can immediately and significantly improve the facial skeleton deficiency, extend the associated soft tissue at the same time, and lay foundation for secondary surgery. MDO can achieve the downgrade of HFM deficiency severity. MDO followed by costochondral graft can get satisfactory esthetic and structural consequence for type III patients.

Three-Dimensional Measurement of Oropharynx and Laryngopharynx in Children With Hemifacial Microsomia.

OBJECTIVE: This study focused on evaluating different parts of the airway in patients with hemifacial microsomia classified by the Pruzansky-Kaban classification system. METHODS: Volumetric and morphologic airway parameters of 66 children with hemifacial microsomia were measured on 3D models. Using the Pruzansky-Kaban system, the patient cohort was composed of seven I-type, 14 IIa type, 27 IIb type, and 18 III type patients. RESULTS: The total airway volume was not statistically different among groups. In the 3D oropharynx models, volume and surface area of the oropharynx decreased from the type I group to the type IIb group. However, no statistically significant difference was found for length (P = 0.965) or minimum cross-sectional area (mini-CSA, P = 0.550) of the oropharynx in the type III group compared to the other groups. In the 3D laryngopharynx models, the mean-CSA (P = 0.413) and mini-CSA (P = 0.378) were not statistically different among groups. In contrast, volume (P = 0.014), length (P = 0.005), and surface area (P = 0.032) of the laryngopharynx were reduced from type I to type III. Kruskal-Wallis analysis indicated statistically significant differences of volume (P = 0.004), length (P = 0.017), and surface area (P = 0.010) of the laryngopharynx among groups I, IIa, and IIb. The mean-CSA (P = 0.247) and mini-CSA (P = 0.206) of the laryngopharynx were not correlated with the different clinical types. CONCLUSION: The mean-CSA varied significantly from type I to IIb at the level of oropharynx. In addition, the volume of the laryngopharynx decreased from type I to type III. However, type III was unique in this study with nonseverely airway measurement results.

Three-Dimensional Measurement of Maxillary Involvement in Hemifacial Microsomia in Children.

In hemifacial microsomia (HFM), the aberrant mandible structure has always been the focus of attention. How the maxillary development being affected is not clear. The authors sought to comprehensively evaluate the hemifacial maxillary deficiency and to assess for Pruzansky-Kaban score correlation.This is a retrospective research of children with HFM. Demographic information were recorded, and computed tomographic scan were reconstructed and analyzed by segmentation, volumetric and cephalometric measurements. Analyses involved paired t-test, independent sample t-test and one-way analyses of variance.Demographic information revealed 67 patients diagnosed with HFM were included: 10.4 percent type I, 38.8 percent IIa, 28.4 percent type IIb, 22.4 percent type III. The maxillary total volume was found to be significantly decreased on the affected side in patients with type IIa (P = 0.0426) and IIb (P = 0.0004). No notable differences in maxillary sinus volume were found. No significant differences in maxillary width measurements were found between groups type I and III. A descending trend in maxillary bone volume ratio, an increasing trend in maxillary posterior width ratio and a decreasing trend in maxillary middle height ratio was observed from group I to IIb (pmbv* = 0.020; pmpw* = 0.002; pmmh* = 0.004).This study comprehensively characterized the hemifacial microsomia maxillary deficiency. For maxillary total volume and transverse development, the type III group presented characteristics similar to the type I group. We concluded that the severity of maxillary deficiency is not completely consistent with the mandibular deformity classification.

Association of Mandibular Dysplasia With Maxillary Volumetric and Linear Measurements in Children With Hemifacial Microsomia.

In hemifacial microsomia (HFM), the correlations between mandibular dysplasia and maxillary deformities in HFM patients have not yet been assessed. The objective of the present study was to examine the association of maxillary volumetric and linear measurements with mandibular ramus height or corpus length on the affected side in children with unilateral HFM.In this retrospective research, a total of 70 children with unilateral HFM were enrolled at our department from 2010 to 2019. Demographic information was recorded, and computed tomographic scan were reconstructed and analyzed by segmentation, volumetric, and cephalometric measurements. Analyses involved independent sample t-test, univariable, and multivariable linear regression.In the overall population, mandibular ramus height (MRH) was positively associated with the maxillary bone volume (MBV) (r = 0.484, P < 0.001) and maxillary total volume (MTV) (r = 0.520, P < 0.001). Similarly, mandibular corpus length (MCL) was significantly associated with the MBV (r = 0.467, P < 0.001) and MTV (r = 0.520, P < 0.001). Multivariate regression analysis revealed that the MRH or MCL were significantly and independently associated with MBV or MTV (MRH/MBV ß = 0.420, P < 0.001; MRH/MTV ß = 0.391, P < 0.001; MCL/MBV ß = 0.403, P < 0.001; MCL/MTV ß = 0.307, P < 0.01).These results demonstrated that the MBV and MTV are independently associated with MRH or MCL on the affected side in children with unilateral HFM, suggesting a potential interaction between mandibular dysplasia and maxillary deformities.

Age estimation using pulp/enamel volume ratio of impacted mandibular third molars measured on CBCT images in a northern Chinese population.

The present study aims to evaluate the relation between chronological age and the ratio of pulp volume (PV) to enamel volume (EV) of impacted mandibular third molars (IMTMs) by using cone-beam computed tomography (CBCT) images and an improved 3D image segmentation technique. A sample of CBCT images of IMTM was collected from 414 northern Chinese subjects (214 male and 200 female clinical patients) ranging in age from 20 to 65 years. The GrowCut effect image segmentation (GCEIS) module algorithm was used to calculate the PV and EV from CBCT images. The total sample was divided into a training group and validation group in a ratio of 7 to 3. The PV/EV ratio (PEr) in the training sample was used to develop a mathematical formula for age estimation as follows: age = - 5.817-21.726 × Ln PEr (p < 0.0001) (Ln, natural logarithm). The mean absolute error (MAE) and root mean square error (RMSE) were used to determine the precision and accuracy of the mathematical formula in the validation group and all samples. The MAEs in the male, female, and pooled gender samples were 9.223, 7.722, and 8.41, respectively, and the RMSEs in the male, female, and pooled gender samples were 10.76, 9.58, and 9.986, respectively. The precise and accurate results indicate that the PEr of IMTM in CBCT images is a potential index for dental age estimation and is possible to be used in forensic medicine.

Microvesicle detection by a reduced graphene oxide field-effect transistor biosensor based on a membrane biotinylation strategy.

Unlike other extracellular vesicle (EV) subtypes such as exosomes, the lack of well-defined universal markers on the surface of microvesicles (MVs) has led to difficulty in the detection of the entire MV population. To design a universal MV detection method, we reported highly sensitive electrical detection of MVs using a reduced graphene oxide (RGO)-based field-effect transistor (FET) biosensor by the introduction of a membrane biotinylation strategy in this work. Biotinylated MVs (B-MVs) were obtained by supplying the culture medium with 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[biotinyl(polyethylene glycol)-2000] (DSPE-PEG-biotin) while cultivating the cells. Excellent biotinylation efficiency of MVs (92.6%) was then realized. A streptavidin (SA) probe was subsequently modified onto the channel surface of the as-fabricated RGO-based FET device, which was capable of specifically recognizing B-MVs due to the high affinity between SA and biotin in a 1 : 4 recognition format. The results showed that the RGO-based FET biosensor could detect B-MVs in a wide range from 105 particles per mL to 109 particles per mL with a low detection limit down to 20 particles per µL, which was the lowest value compared with other previously reported results. This platform also allowed distinguishing B-MVs from other unbiotinylated EV types such as MVs and exosomes, exhibiting excellent specificity. Moreover, this FET biosensor demonstrated the capability of detecting B-MVs derived from different cell lines including cancer cells and normal cells, indicating its versatility and potential applications in the biomedical field.

Third molar maturity index (I3M) for assessing age of majority in northern Chinese population.

In many countries, assessment of legal age, also known as age of majority, has become increasingly important over the years. In China, individuals older than 18 years of age have full capacity regarding civil conduct and can be tried as an adult for criminal charges. Therefore, from a legal point of view, it is crucial to determine whether an individual is an adult. The developmental degree of the third molar is widely recognized as a suitable site for age estimation in late adolescence. This article uses the third molar maturity index (I3M) with a cutoff value of I3M = 0.08, which was established by Cameriere et al. in 2008, to distinguish whether an individual is a minor or an adult (≥ 18 years of age) in a northern Chinese population. A total of 840 digital orthopantomograms (OPTs) from 420 male and 420 female northern Chinese subjects aged 12 to 25 years were evaluated. It was found that an increase in I3M corresponded to a decrease in chronological age. In our study, I3M = 0.10 showed better accuracy in age discrimination in both men and women. This threshold also resulted in high sensitivity (0.929 and 0.809) and specificity (0.940 and 0.973) in males and females, respectively. The proportion of correctly classified subjects was 0.917 (95% CI, 0.898 to 0.935) in total, 0.938 (95% CI, 0.915 to 0.961) in male and 0.895 (95% CI, 0.866 to 0.925) in female subjects. Bayes post-test probabilities were 0.967 (95% CI, 0.947 to 0.986) in males and 0.983 (95% CI, 0.966 to 0.998) in females. These differences in threshold values between Chinese and Caucasian populations might be because the development of third molars is delayed in the Chinese population compared to the Caucasian population. In conclusion, I3M might be a useful method in legal and forensic practices to determine ages in late adolescence in northern Chinese individuals. However, a specific population should be tested before I3M is used for legal age estimation.

3D bioprinting mesenchymal stem cell-laden construct with core-shell nanospheres for cartilage tissue engineering.

Cartilage tissue is prone to degradation and has little capacity for self-healing due to its avascularity. Tissue engineering, which provides artificial scaffolds to repair injured tissues, is a novel and promising strategy for cartilage repair. 3D bioprinting offers even greater potential for repairing degenerative tissue by simultaneously integrating living cells, biomaterials, and biological cues to provide a customized scaffold. With regard to cell selection, mesenchymal stem cells (MSCs) hold great capacity for differentiating into a variety of cell types, including chondrocytes, and could therefore be utilized as a cartilage cell source in 3D bioprinting. In the present study, we utilize a tabletop stereolithography-based 3D bioprinter for a novel cell-laden cartilage tissue construct fabrication. Printable resin is composed of 10% gelatin methacrylate (GelMA) base, various concentrations of polyethylene glycol diacrylate (PEGDA), biocompatible photoinitiator, and transforming growth factor beta 1 (TGF-ß1) embedded nanospheres fabricated via a core-shell electrospraying technique. We find that the addition of PEGDA into GelMA hydrogel greatly improves the printing resolution. Compressive testing shows that modulus of the bioprinted scaffolds proportionally increases with the concentrations of PEGDA, while swelling ratio decreases with the increase of PEGDA concentration. Confocal microscopy images illustrate that the cells and nanospheres are evenly distributed throughout the entire bioprinted construct. Cells grown on 5%/10% (PEGDA/GelMA) hydrogel present the highest cell viability and proliferation rate. The TGF-ß1 embedded in nanospheres can keep a sustained release up to 21 d and improve chondrogenic differentiation of encapsulated MSCs. The cell-laden bioprinted cartilage constructs with TGF-ß1-containing nanospheres is a promising strategy for cartilage regeneration.

One-Year Relapse of Mandibular Distraction for Hemifacial Microsomia Using Masseteric Botulinum Toxin Type A Injections.

BACKGROUND: The relapse of hemifacial microsomia was thought to be highly related to the soft tissue envelope around the mandible angle mainly composed by masseter and medial pterygoid. According to the reason, we tried to apply masseter injection of type A botulinum toxin to weaken the soft envelope tension on the early stage post mandible distraction in adult HFM patients. METHODS: Eight patients diagnosed with HFM were studied and randomly assigned to an experimental or control group. Patients in the experimental group were treated with DO, orthognathic surgeries, autologous fat grafting, and bilateral masseter muscle injection with type A botulinum toxin. The patients in control group were treated with the same procedures as the patients in experimental group except for masseter muscle injection with type A botulinum toxin. The recurrence rates of both groups were evaluated and analyzed after nearly 1 year of follow-up. RESULTS: The mean recurrence rate was 26.30% ±â€Š11.84% (range 7.62%-37.27%) in the 8 patients after 1-year follow-up. The relapse rate was 16.32% ±â€Š7.78% (7.62%-26.22%) in the experimental group and 36.28% ±â€Š1.03% (34.84%-37.27%) in the control group. There was a significant difference (P = 0.002) between the experimental group and the control group. CONCLUSIONS: The combination of DO, orthognathic surgeries, autologous fat particle transplantation, and masseter muscle type A botulinum toxin injection technique could be a comprehensive treatment plan for adult patients of HFM. Furthermore, masseter injection of type A botulinum toxin might be an alternative method to reduce the early recurrence rate of postoperative adult patients of HFM.

Age estimation in northern Chinese children by measurement of open apices in tooth roots.

The aim of this study was to assess the accuracy of Cameriere's methods on dental age estimation in the northern Chinese population. A sample of orthopantomographs of 785 healthy children (397 girls and 388 boys) aged between 5 and 15 years was collected. The seven left permanent mandibular teeth were evaluated with Cameriere's method. The sample was split into a training set to develop a Chinese-specific prediction formula and a test set to validate this novel developed formula. Following the training dataset study, the variables gender (g), x 3 (canine teeth), x 4 (first premolar), x 7 (second molar), N 0, and the first-order interaction between s and N 0 contributed significantly to the fit, yielding the following linear regression formula: Age = 10.202 + 0.826 g - 4.068x 3 - 1.536x 4 - 1.959x 7 + 0.536 N 0 - 0.219 s [Symbol: see text] N 0, where g is a variable, 1 for boys and 0 for girls. The equation explained 91.2 % (R (2) = 0.912) of the total deviance. By analyzing the test dataset, the accuracy of the European formula and Chinese formula was determined by the difference between the estimated dental age (DA) and chronological age (CA). The European formula verified on the collected Chinese children underestimated chronological age with a mean difference of around -0.23 year, while the Chinese formula underestimated the chronological age with a mean difference of -0.04 year. Significant differences in mean differences in years (DA - CA) and absolute difference (AD) between the Chinese-specific prediction formula and Cameriere's European formula were observed. In conclusion, a Chinese-specific prediction formula based on a large Chinese reference sample could ameliorate the age prediction accuracy in the age group of children.

Fronto-Orbital Osteotomy Reshaping for Supraorbital Ridge Protrusion.

BACKGROUND: Supraorbital ridge protrusion is an unpleasant facial characteristic in China. Literature describing the surgical correction of supraorbital ridge protrusion is scarce. OBJECTIVE: This study aimed to present a surgical technique for correcting supraorbital ridge protrusions. METHOD: The anterior wall of the frontal sinus and the outer cortex of the frontal bone were removed to form a frontal bone flap, which was regrafted after being trimmed to suitable shape and size. Microabsorbable or titanium plates and screws were fixed on the bilateral side of the bone flap. Anteroposterior depth (the distance between the anterior and posterior wall of the frontal sinus, A-PD), nasofrontal angle, and forehead inclination were measured on the middle sagittal plane before and after corrective operation. RESULT: All patients got satisfactory appearances in this study. All the variations of measurements showed that the excessive prominent supraorbital ridge had been improved significantly. The result of the Wilcoxon signed-rank test showed that the P value for A-PD was 0.043, which indicated that there were significant statistical differences between preoperative and postoperative A-PD in the midsagittal plane. No recurrence or complications were found during 1 year of follow-up. CONCLUSIONS: The fronto-orbital reshaping osteotomy is a reliable technique for correcting supraorbital ridge protrusions. Major complications were not observed and satisfying appearances were obtained.

Surgical guide assistant mandibular distraction osteogenesis and sagittal split osteotomy in the treatment of hemifacial microsomia.

BACKGROUND: Hemifacial microsomia is the second most common congenital craniofacial malformation after cleft lip/palate with a wide variety of pathologic expression in jaws, skeletal components, ears, and soft tissues. Among the deformities, mandibular hypoplasia is the most common and is the main component that affects facial asymmetry. Mandibular distraction osteogenesis is the mainstay treatment; however, the vector of device and osteotomy lines need to be well designed. We utilized the sagittal split osteotomy for mandibular distraction with rapid prototyping surgical guide plate, making a successful outcome. METHODS: Hemifacial microsomia with unilateral Pruzansky II mandibular hypoplasia were selected in this study. Three-dimensional CT reconstructive data was put into Proplan CFM for preoperative designing and then manufacturing the surgical guide plate. The mandibular osteotomy and implantation of the internal distractor were performed through an intraoral approach aided with the prefabricated guide plate. Distraction began 7 days postoperation with a frequency of 1 mm/d and the distractor was kept in place 6 to 10 months after the first operation, then the distractor was removed. RESULTS: From July 2012 to March 2014, 6 cases of Pruzansky II hemifacial microsomia aged from 7 to 11 years were treated with the technique mentioned above. The range of distraction extends from 20 to 30 mm. The facial asymmetry deformities were improved obviously and without any complication. CONCLUSIONS: Mandibular distraction osteogenesis by sagittal split osteotomy through rapid prototyping surgical guide plate provides certain advantages in the treatment of hemifacial microsomia.

[Evaluation of the 5-year clinical restoration effect of implants retained complete overdentures with Locator attachments in 48 patients].

PURPOSE: To observe the long-term clinical effect of implants retained complete overdentures with Locator attachments. METHODS: A total of 48 patients with edentulous jaws treated with implants retained complete overdentures with Locator attachments were selected from the Outpatient Department of Peking University School and Hospital of Stomatology from 2016 to 2017. Among them, 21 patients underwent double-maxillary complete overdentures restoration and 27 patients underwent single-maxillary restoration. A total of 230 implants were implanted. The clinical observation indicators included the implant survival rate, peri-implant mucosal bleeding on probing(BOP), the change in the vertical height of alveolar bone absorption around the implants, overdenture base fracture rate, artificial tooth fall off and fracture rate and other complications. The change of the locator attachment retention force of the implant-supported overdentures was evaluated. SPSS 13.0 software package was used for data analysis. RESULTS: During the five-years clinical observation period, 5 implants fell off, 1 narrow dimeter implant in the anterior zone was broken, and 12 implants were lost to follow-up. The implant survival rate was 97.25%. One year after the restoration therapy finished, peri-implant mucosal bleeding on probing (BOP+) was detected in 48 (21.4%) implants. The average BI was 0.21±0.42, which was higher in the anterior zone than that in the posterior zone. The vertical alveolar bone absorption height around the implants was (0.21±0.35) mm, 2 implants-supported complete overdenture bases were broken. After 5 years of restoration, 163(76.89%) implants had peri-implant mucosal bleeding on probing(BOP+). The average BI was 1.00±0.70, and the vertical alveolar bone absorption height around the implants was (0.58±0.85) mm. There was no significant difference between males and females. There was no significant difference in the peri-implant mucosal bleeding index and the alveolar bone vertical absorption height between the anterior zone and the posterior zone(P＞0.05). The mean BI of peri-implant mucosa and the vertical absorption height of peri-implant alveolar bone were significantly different between the 1-year observation period and the 5-year observation period respectively(P＜0.01). There were 17(26.15%) cases with overdenture bases fracture, and the fracture rate of artificial teeth was 16.92%. Most of them occurred in the midline area of the anterior zone and the location of the overdenture base on the locator attachments. The average first replacement time of the locator attachment nylon retainer washer was 34.2±10.3 months. CONCLUSIONS: Implants retained complete overdentures with Locator attachments are effective in long term clinical observation. Complications are mainly found in peri-implant mucosal bleeding on probing and vertical alveolar bone absorption, and tended to increase gradually over time. The fracture of the implant retains complete overdenture bases and the fall off or fracture of the artificial teeth are the second serious complications. Overdenture base with metal frame at the location of the Locator abutment and the midline of the anterior area should be strengthened, and narrow diameter implants should be avoided as far as possible in the anterior zone.

3D-CT measurements of facial symmetry in severe CFM patients: A comparative study between mandibular ascending ramus distraction osteogenesis and bone grafting.

This study aims to compare the effects of mandibular distraction osteogenesis (MDO) and bone grafting on the facial symmetry of children with Pruzansky-Kaban type IIB and III craniofacial microsomia (CFM). Medical records and three-dimensional computed tomography (3D-CT) data of CFM patients who had primarily undergone MDO and bone grafting were collected. A retrospective analysis of pre-and post-operative 3D imaging data was conducted to compare the improvement rate in facial symmetry between the two groups based on occlusal cant, affected/unaffected ramus height ratio and chin point deviation. The data were tested for normality using the Shapiro-Wilk test. When the data followed a normal distribution, a paired sample t-test was employed for the comparison between preoperative and postoperative data. When the data did not follow a normal distribution, the Wilcoxon signed-rank test for paired samples was used for preoperative and postoperative comparison. The study included 18 children with type IIB and III CFM, 11 in the MDO group and 7 in the bone grafting group. In the MDO group, postoperative Gn-FH and Gn-Cor distances increased significantly, whereas the postoperative Gn-Mid distance decreased significantly. Occlusal cant decreased significantly and ramus height affected/unaffected ratio increased significantly after MDO. In the bone graft group, there was no statistically significant difference in the postoperative ratios of chin deviation, occlusal cant, and ramus height affected/unaffected compared to the preoperative values. Compared to bone grafting, MDO can significantly enhance ramus height ratio, level occlusal plane, and centralize the chin point among patients with CFM. Furthermore, MDO achieves superior enhancements in facial symmetry.

Porous titanium-6 aluminum-4 vanadium cage has better osseointegration and less micromotion than a poly-ether-ether-ketone cage in sheep vertebral fusion.

Interbody fusion cages made of poly-ether-ether-ketone (PEEK) have been widely used in clinics for spinal disorders treatment; however, they do not integrate well with surrounding bone tissue. Ti-6Al-4V (Ti) has demonstrated greater osteoconductivity than PEEK, but the traditional Ti cage is generally limited by its much greater elastic modulus (110 GPa) than natural bone (0.05-30 GPa). In this study, we developed a porous Ti cage using electron beam melting (EBM) technique to reduce its elastic modulus and compared its spinal fusion efficacy with a PEEK cage in a preclinical sheep anterior cervical fusion model. A porous Ti cage possesses a fully interconnected porous structure (porosity: 68 ± 5.3%; pore size: 710 ± 42 µm) and a similar Young's modulus as natural bone (2.5 ± 0.2 GPa). When implanted in vivo, the porous Ti cage promoted fast bone ingrowth, achieving similar bone volume fraction at 6 months as the PEEK cage without autograft transplantation. Moreover, it promoted better osteointegration with higher degree (2-10x) of bone-material binding, demonstrated by histomorphometrical analysis, and significantly higher mechanical stability (P < 0.01), shown by biomechanical testing. The porous Ti cage fabricated by EBM could achieve fast bone ingrowth. In addition, it had better osseointegration and superior mechanical stability than the conventional PEEK cage, demonstrating great potential for clinical application.

Severe bone resorption in expanded polytetrafluoroethylene chin augmentation.

Expanded polytetrafluoroethylene implant is usually considered as a wonderful implant for chin cosmetic augmentation with no or less bone resorption compared with solid silicone implant. However, one severe bony erosion in expanded polytetrafluoroethylene chin augmentation was found in our clinical work. We consider that the possible reason about severe bone resorption in such situation is most relative to the mentalis muscle hyperactivity, rather than the kinds of materials. We also strongly advise that genioplasty is suitable for the cases with mentalis muscle hyperactivity caused by a dentofacial deformity.

Condylar resorption post mandibular distraction osteogenesis in craniofacial microsomia: A retrospective study.

The aim of this study was to investigate the characteristics of condylar resorption in craniofacial microsomia (CFM) patients following mandibular distraction osteogenesis (MDO). Patients with unilateral type-IIa and type-IIb CFM, who had completed MDO and mandibular distractor extraction (MDE), were recruited. The height and volume of the condyle were measured on three-dimension models created by the analysis of computed tomography (CT) data. Normality analysis was performed using the Shapiro-Wilk test. Data for the affected and unaffected sides were compared using the paired t-test or Wilcoxon signed-rank test. Data for both type-IIa and type-IIb CFM were compared using the independent-samples t-test or Mann-Whitney U test. The Pearson or Spearman correlation was used to determine the correlations of condylar resorption rate with related measurements. In total, 48 type-IIa and 48 type-IIb CFM patients were included. The condylar resorption rate in type-IIa CFM (0.35 ± 0.32) was significantly associated with the height of the condyle (r = 0.776, p < 0.001) and distraction distance (r = 0.447, p = 0.001), while the condylar resorption rate in type-IIb CFM (0.49 ± 0.46) was significantly associated with the height of the condyle (r = 0.924, p < 0.001). However, there was no significant difference in condylar resorption rate between type-IIa and type-IIb CFM (p = 0.075). In addition to occlusal changes, no other negative symptoms of the TMJ were observed with condylar resorption. Condylar resorption was evident in CFM patients following mandibular distraction osteogenesis, and the condylar resorption rate showed a relationship with distraction distance and condylar height.

Respiratory outcome of mandibular distraction osteogenesis on obstructive sleep apnea in craniofacial microsomia: A retrospective study.

This study aimed to evaluate the effect of mandibular distraction osteogenesis (MDO) on respiratory function in CFM patients with obstructive sleep apnea (OSA) according to polysomnography (PSG). This study retrospectively analyzed patients with CFM who underwent PSG before surgery and after completion of mandible distraction. Patients who met the inclusion criteria were selected. The Pediatric Sleep Questionnaire (PSQ) was used to assess patients' signs and symptoms related to OSA. The obstructive apnea-hypopnea index (OAHI) and lowest oxygen saturation (LSaO2) were imported into SPSS version 26.0. The Wilcoxon signed-rank test was used to assess the differences in PSG before and after MDO. Other data were described using descriptive statistics. A P-value less than 0.05 was considered statistically significant. A total of 25 unilateral CFM patients were included in this study. Most patients (72%) had mild OSA; moderate and severe OSA were 12% and 16%, respectively. Snoring (52%) was the most common symptom among these patients. After completion of mandibular distraction, snoring and other OSA-related symptoms were significantly improved. Twelve patients had normalized PSG and the severity of OSA improved significantly in 3 patients. The total effective rate of MDO for OSA was 60%. The statistical results showed that OAHI (P = 0.045) decreased and LSaO2 (P = 0.009) increased significantly compared to preoperative values. MDO can improve OSA-related symptoms in CFM patients. In addition, respiratory function was improved in most patients after MDO, based on PSG. CFM patients, especially those with OSA, can benefit from MDO.