Dietary signals in the premolar dentition of primates.

Dietary adaptations specific to the premolar row remain largely undocumented across primates. This study examines how relative premolar size varies among broad dietary groups (i.e., folivores, frugivores, insectivores, hard-object feeders) using a phylogenetically and ecologically diverse sample of species. We quantified relative premolar size with shape ratios computed using mandibular length, body mass, palate area, and M1 area to evaluate hypotheses that link variation in relative premolar size to differences in tooth loading, energy requirements, the probability of tooth-food-tooth contact during mastication, and shifts in preferred bite point. Our results revealed the following dietary signals. First, primate folivores have large premolar rows relative to palate area in comparison to frugivores and insectivores. This contrast is consistent with the hypothesis that folivores require large postcanine teeth relative to the size of the oral cavity to increase the probability of particle fracture during mastication. Second, hard-object feeders are distinct from other groups in having P4s that are large relative to their M1s. This morphology is not associated with an increase in the size of the premolar row relative to mandibular length. This combination challenges the idea that hard-object feeders have large premolars as an adaptive response to resisting the loads incurred when processing mechanically challenging foods. We therefore interpret the large P4/M1 ratios of hard-object feeders as indicating greater functional integration across the premolar-molar boundary owing to a mesial shift in preferred bite point. Finally, in a restricted subset of anthropoids, we found that, relative to mandibular length, premolar area increases with dietary elastic modulus (E) and toughness (R), indicating that relative premolar size is evolutionarily sensitive to food mechanical properties. Thus, our results show that relative premolar size is correlated with diet, highlighting the importance of this region for understanding the evolutionary history of primate dietary adaptations.

C1-C2 sublaminar taping for displaced odontoid synchondrosis fracture in an infant: A case report and novel surgical technique.

Pediatric cervical spine injuries are rare, and the diagnosis and management can be challenging. Surgical intervention has been recommended in unstable odontoid synchondrosis injuries or those that have failed nonoperative measures. However, the literature remains sparse on the operative management of severe injuries due to the low incidence. An 18-month-old female sustained an unstable odontoid synchondrosis fracture from a motor vehicle accident. Due to ongoing instability after initial immobilization in a halo, the decision was made to proceed with surgical management. With the patient positioned prone and neural monitoring throughout, a posterior approach was utilized. Subperiosteal exposure of the C1 posterior arch was performed bilaterally. A spinal fixation band was passed under the right C1 posterior arch, around the C2 spinous process, under the left C1 posterior arch, and finally back under the C2 spinous process. The C1-C2 distraction was reduced using intraoperative imaging, and the sublaminar tape construct was secured and reinforced. The halo was then reattached. Postoperative recovery was complicated by a halo pin-site infection which was treated with oral antibiotics. The halo was removed after 3 months, following a computerized tomography that demonstrated union. X-rays at 6 months revealed anatomical alignment with the union. Surgery is recommended in pediatric odontoid synchondrosis fractures refractory to nonoperative management. Sublaminar taping of C1-C2 with a spinal fixation band has been demonstrated to be an effective surgical technique in the management of an unstable odontoid synchondrosis fracture.

Novel PAradigm to improve Inflammatory burden in end stage Renal disease (rePAIR): study protocol for a randomized controlled trial.

BACKGROUND: Given the importance of inflammation as a predictor of poor outcomes in End Stage Renal Disease (ESRD), reductions in inflammatory biomarkers have been proposed as a critical target in this population. This study targets chronic periodontitis, an oral inflammatory disease of microbial etiology causing persistent inflammation in ESRD. Unlike the previously reported episodic periodontal interventions, we propose to control periodontal inflammation with a continuous maintenance and oral health behavior modifications. We hypothesize that this strategy will improve systemic inflammation and oxidative stress, oral health and quality of life within the 6-month observation period. METHODS: The rePAIR (novel PAradigm to improve Inflammatory burden in ESRD) study is a pilot and feasibility, parallel-arm, and randomized controlled clinical trial that will recruit 72 ESRD subjects with periodontitis in a model of computerized block randomization. This trial aims to compare the effect of standard-of-care vs. repeated non-surgical periodontal therapy on systemic and oral inflammatory burden. This trial will recruit ESRD adult patients with periodontitis older than 21 years old with a minimum of 12 teeth and no history of periodontal treatment within a year. The trial will examine serum C-reactive protein (CRP) (primary outcome) as a biomarker of inflammation as well as interleukin-6 (IL-6), F2 isofurans and F2 isoprostanes (secondary outcomes) and compare their difference between groups from baseline to 6 months. The trial will also compare the difference between groups in patient-centered and clinical oral outcomes from baseline to 6 months. DISCUSSION: The trial follows a rigorous and transparent study design capturing elements such as pre-specified eligibility criteria, pre-specified primary and secondary outcomes, detailed intervention description to allow replication, intervention random allocation and concealment, blinding in outcome assessment, appropriate sample size calculations, explanation of interim analysis, as per CONSORT Guidelines. Further, gender diversity is secured not only at recruitment but also throughout the trial and during the analysis. Therefore, treatment response outcomes will be examined per gender category. In order to manage anticipated problems, the protocol has included alternative approaches. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03241511 . Registered on 7 August 2017.