Aged and induced-premature ovarian failure mouse models affect diestrus profile and ovarian features

Sex hormones exert a wide influence on several systems of the human body, especially in women, who undergo intense changes in the trans and postmenopausal periods. Different experimental models are used to mimic these conditions; however, the impact on hormonal profile may be different. This study aimed to analyze and compare vaginal cytology of different post-estropausal mice models, along with their microscopical ovarian features. Forty-six C57BL/6J female mice with the ages of 4, 6 and 18 months at the beginning of the experiment, weighing about 25-28 grams, constituted five groups: NC-(negative control) animals with no treatment, OVX-SHAM-sham ovariectomized, OVX-ovariectomized, VCD-medicated with 160 mg/kg/day of 4-vinylcyclohexene diepoxide via IP for 20 consecutive days, and Aged-senescent mice under physiological estropause. Euthanasia was performed at different periods for the removal of the ovaries, and after diestrus was confirmed by vaginal cytology for 10 consecutive days. For daily vaginal cytology, morphological and histomorphometric microscopic analyzes were performed. Aged mice presented significant increased neutrophils when compared to VCD group, as well as increased cornified epithelial cells when compared to OVX mice, and also increased nucleated epithelial cells when compared to VCD and OVX. NC and OVX-SHAM ovaries presented innumerous follicles at different stages of development, while VCD showed marked follicular atresia, depleted of primordial or developing follicles and a predominance of interstitial cells. The ovaries of aged mice were predominantly constituted by corpus luteum degenerated into corpus albicans, with rare antral follicles. All analyzed models led to different permanent diestrus profiles caused by each model, as indicated by ovarian features. This should be carefully considered when choosing a post-estropausal experimental model, in order to better correlate this challenging phase of female's life with physiological/pathological conditions.

Influence of age and gender on alveolar bone healing post tooth extraction in 129 Sv mice: a microtomographic, histological, and biochemical characterization

OBJECTIVES

To analyze the effect of biological sex and aging on craniofacial bone features in 129 Sv mice and their influence on dental socket healing post tooth extraction.

MATERIALS AND METHODS

A total of 52 129 Sv mice were used, of which 28 were young (3-4 months) and 24 were aged (17-18 months), equally distributed according to biological sex. After an upper right incisor extraction, mice specimens were collected at 7, 14, and 21-days post-surgery for microtomographic (microCT) and comprehensive histological analysis. Mandible, skull bones, and maxillae at 21 days were analyzed by microCT, while blood plasma samples were collected for the detection of key bone turnover markers (P1NP and CTX-1) by enzyme-linked immunosorbent (ELISA) assay.

RESULTS

Aged females depicted significantly decreased mineralized bone content in alveolar sockets in comparison to young females and aged males at day 7, and aged males at day 14. Mandible RCA and Ma.AR of aged females were also significantly decreased in comparison with young females. Histological evaluation revealed that all alveolar sockets healed at 21 days with inflammation resolution and deposition of new bone. Immunohistochemistry for TRAP revealed increased area density for osteoclasts in alveolar sockets of aged females when compared to young females at 21 days. While a significant increase in CTX-1 levels was detected in blood plasma of aged females when compared to young females, P1NP levels did not significantly change between young and older females. No significant changes were observed for males.

CONCLUSIONS

Age and gender can significantly affect craniofacial bones of 129 Sv mice, especially maxilla and mandible in females. Considering the altered bone resorption parameters and delayed alveolar bone healing in older females, careful deliberation is necessary during development of pre-clinical models for craniofacial research.

CLINICAL RELEVANCE

Aging can be a contributing factor to slower bone healing in craniofacial bones. However, there are no sufficient experimental studies that have addressed this phenomenon along with biological sex taken into consideration.

Occlusal Instability Results in Increased Complication Rates After Treatment of Mandibular Fractures

PURPOSE

It is important to understand the factors that can increase the incidence of complications after mandibular fracture (MF) treatment. The objective of the present study was to investigate whether occlusal stability influences the occurrence of postoperative complications in MFs treated with internal rigid fixation.

PATIENTS AND METHODS

We performed a prospective cohort study of patients treated for MF by osteosynthesis with plate and screw fixation. The primary predictor variable was the occlusal stability (yes vs no). Occlusion was scored as stable (group 1) if the patients had all their teeth and no free ends in either dental arch. Occlusion was coded as unstable (group 2) if the patients were partially edentulous with free ends in either dental arch or had edentulism involving more than 6 dental elements. The primary outcome variable was postoperative complication (yes vs no). The secondary outcome variables were the osteosynthesis system used (2.0 or 2.4 mm), local factors, age, and gender. Statistical analysis was performed using the χ² statistical test at 5% significance.

RESULTS

Of 115 patients with 121 MFs, 73 (63.48%) had stable occlusion (group 1) and 42 (36.52%) had unstable occlusion (group 2). The mean age was 34.11 years, and 71.3% were men. The postoperative complication rate was 8.70% (10 patients). Of the 10 patients with complications, 3 (2.6%) were in group 1 and 7 (6.1%) were in group 2 (P = .021 and P < .05, respectively). The 2.0-mm system was used in 107 cases (93%). All the complications were associated with use of the 2.0-mm osteosynthesis plates, occurring in 3 of 69 patients in group 1 (4.34%) and 7 of 38 patients in group 2 (18.42%; P = .032 and P < .05, respectively). The greatest number of complications was associated with unilateral MF (9 of 109). The occurrence of postoperative complications in angle and symphysis/parasymphysis fracture sites was equal.

CONCLUSIONS

The results of the present study suggest that unstable occlusion could increase the rate of postoperative complications in MFs treated with plates and screws. Future studies are required with occlusal stability included as a variable.

Immediate Oral Rehabilitation Using Dental Implants After Marginal Mandibulectomy: A Case Report

Mandibular reconstruction techniques are always a challenge to oral and maxillofacial (OMF) surgeons. Techniques and treatment plans that offer the patient OMF rehabilitation should always be available. Technological innovations have enabled more rapid, safer, and more secure treatment than in the past. This article describes a case using a different approach. The patient was treated with marginal mandibulectomy and immediate rehabilitation with osseointegrated implants; a hybrid prosthesis was fabricated a short time thereafter. This treatment plan demonstrated its utility and efficiency in this case. An approach with fewer surgeries and OMF rehabilitation needs be considered in all cases.