Collagen mutation and age contribute to differential craniofacial phenotypes in mouse models of osteogenesis imperfecta.

Craniofacial and dentoalveolar abnormalities are present in all types of osteogenesis imperfecta (OI). Mouse models of the disorder are critical to understand these abnormalities and underlying OI pathogenesis. Previous studies on severely affected OI mice report a broad spectrum of craniofacial phenotypes, exhibiting some similarities to the human disorder. The Brtl/+ and G610c/+ are moderately severe and mild-type IV OI, respectively. Little is known about the aging effects on the craniofacial bones of these models and their homology to human OI. This study aimed to analyze the Brtl/+ and G610c/+ craniofacial morphometries during aging to establish suitability for further OI craniofacial bone intervention studies. We performed morphological measurements on the micro-CT-scanned heads of 3-wk-old, 3-mo-old, and 6-mo-old female Brtl/+ and G610c/+ mice. We observed that Brtl/+ skulls are shorter in length than WT (P < .05), whereas G610c/+ skulls are similar in length to their WT counterparts. The Brtl/+ mice exhibit alveolar bone with a porotic-like appearance that is not observed in G610c/+. As they age, Brtl/+ mice show severe bone resorption in both the maxilla and mandible (P < .05). By contrast, G610c/+ mice experience mandibular resorption consistently across all ages, but maxillary resorption is only evident at 6 mo (P < .05). Western blot shows high osteoclastic activities in the Brtl/+ maxilla. Both models exhibit delayed pre-functional eruptions of the third molars (P < .05), which are similar to those observed in some bisphosphonate-treated OI subjects. Our study shows that the Brtl/+ and G610c/+ mice display clear features found in type IV OI patients; both show age-related changes in the craniofacial growth phenotype. Therefore, understanding the craniofacial features of these models and how they age will allow us to select the most accurate mouse model, mouse age, and bone structure for the specific craniofacial bone treatment of differing OI groups.

Immediate Teeth in Fibulas Versus Standard Fibula Free Flap: A Comparison of Donor Surgical Site Infections.

BACKGROUND: Immediate placement of dental implants with dental restoration at the leg donor site requires implant components and prosthetic materials that are not packaged sterile. PURPOSE: This study aimed to determine if there was a difference in donor surgical site infection between patients that received a fibula free flap with dental implants and immediate teeth (ITFFF: immediate teeth fibula free flap) before flap transfer to the defect site when compared to standard fibula free flaps (SFFFs) without dental implant placement. STUDY DESIGN, SETTING, SAMPLE: A retrospective cohort study was designed and implemented. The study population was composed of patients who underwent free fibula flap transfer for the treatment of benign or malignant conditions of the head and neck from 2015 to 2022. Patients who received immediate dental implants without teeth were excluded, since those implants are sterile and buried under soft tissue. PREDICTOR VARIABLE: The surgical treatment with either ITFFF or SFFF was treated as the primary predictor variable. MAIN OUTCOME VARIABLE: The primary outcome variable was postoperative donor surgical site infection. COVARIATES: There were 12 covariate variables including age, sex, diabetes diagnosis, immunosuppression/prior chemotherapy treatment, body mass index, smoking status, pack year history, pathology treated, technique for fibula donor site closure, skin paddle harvest, skin paddle area (cm2), and negative pressure wound therapy. ANALYSES: For the effect of the covariates on the primary predictor variable, χ2 analyses and t-tests were used. The effect of the primary predictor variable on the primary outcome was evaluated using χ2 analysis. A P value of < 0.05 was considered statistically significant. RESULTS: There were 37 patients in the ITFFF group and 47 in the SFFF group. The donor site infection rate for the entire study population was 2.38%. In the ITFFF group, there was 1 donor surgical site infection (2.70%), and in the SFFF group there was also 1 donor surgical site infection (2.13%). There was no significant difference in donor surgical site infection between the groups (P = .86). CONCLUSION AND RELEVANCE: This study found no difference in donor surgical site infection rates between patients who received ITFFF versus SFFF. The overall donor surgical site infection rate following fibula free flap is low.

Squamous Cell Carcinoma of the Tongue in Young Patients: A Case Series and Literature Review.

PURPOSE: The purpose of this study was to describe 3 cases of tongue cancer in patients less than 21 years of age. Secondarily, a literature review was performed to examine disease presentation, risk factors, prognosis, and treatment strategies for young persons with tongue cancer. METHODS: The authors presented 3 cases of childhood tongue cancer between 2009 and 2020 at the University of Michigan Department of Oral and Maxillofacial Surgery (Ann Arbor, MI). An electronic literature review was conducted via PubMed, Embase, Web of Science, and MLibrary. RESULTS: Including the present case series, 64 studies reporting 108 cases were identified. Age at presentation ranged from newborn to 20 years, with a mean age of 14.5 years. The majority of patients were female (52.2%); 68.1% of patients presented with T1 or T2 disease. Nodal metastases were seen in 56.1% of patients. The most commonly identified predisposing factors included Fanconi anemia (13.9%), bone marrow transplant (9.3%), tobacco use (6.5%), and xeroderma pigmentosum (4.6%). Most patients received surgery alone (37.5%), followed by surgery with adjuvant radiation (33.8%); 60.6% underwent neck dissection. Overall survival was 60.3% at 1 year and 43.6% at 5 years. CONCLUSIONS: Oral tongue cancer in the young is a rare disease with poorly understood etiology. There is a need for oncologists and maxillofacial surgeons to collaborate in the study of genetic, social, environmental, and medical risk factors contributing to the disease. All patients should undergo high-throughput genetic sequencing to expand our understanding of the disease process and allow for targeted treatment strategies.