Brachytherapy-Mediated Bone Damage in a Rat Model Investigating Maxillary Osteoradionecrosis

Abstract

Similar to the mandible, the maxilla is susceptible to radiogenic bone injury as demonstrated by the significant decrease in bone volume of the radiated dental extraction socket. Despite radiologic similarities to mandibular ORN in the rat model, the maxilla demonstrated a more benign clinical course with a complete absence of bone exposure. Differences in the maxillary bone and microenvironment of the maxilla compared with the mandible may explain the subclinical response to radiation and lower incidence of maxillary ORN seen in patients. This maxillary model can be combined with our high-dose-rate mandibular ORN model to investigate these differences and better understand ORN.

Onset of mandible and tibia osteoradionecrosis: a comparative pilot study in the rat

“…Although severity of osteonecrosis can be assessed in histological sections based on loss of viable osteocytes 11, 17 , the earliest histological criteria for definitive diagnosis of osteonecrosis are still debatable due to its multifactorial etiology from radiation, drugs, alcohol, infection and trauma 6, 24, 27, 37 . This pilot study involves a limited number of experimental animals but it is consistent with a previous ORN study that showed that limited sample size can still be used to define skeletal outcomes of radiation 38 . Despite the limited sample size, the outcomes suggest apparent site-disparity in the onset and cellular features of ORN in the jaws relative to long bones with mandible being more susceptible to ORN than tibia.…”

Micro-CT analysis of the rodent jaw bone micro-architecture: A systematic review

“…Six studies applied in vivo micro-CT, performed in the maxilla [6], [15], [20], [21] and in the condyle [10], [22]. The scanning device which was most often used was the μCT 40 (Scanco Medical, Brüttisellen, Switzerland) [9], [11], [13], [14], [19], [23], [24], [25], [26], [27], [28], [29], [30], [31], followed by the Skyscan apparatus (Skyscan, Aartselaar, Belgium) [3], [4], [8], [20], [21], [32], [33], [34], [35]. The results of the quantitative analysis are presented in Table 2, Table 3, Table 4.…”

“…Furthermore, the most frequently analysed regions of interest were the alveolar bone surrounding the first molar tooth and the interradicular septal bone. The effect of drug interventions on the maxillar bone was investigated in 4 studies [3], [8], [16], [23], with extraction sockets as region of interest for assessing the drug-induced bone response. Only 1 study [9] focused on the effect of mechanical loading on the alveolar bone.…”

“…Only 1 study [9] focused on the effect of mechanical loading on the alveolar bone. Finally, concerning the type of animals used, Sprague–Dawley rats were used in the majority of the studies (n = 10) [3], [4], [6], [8], [9], [14], [16], [23], [24], [35], with an age varying from 12 days to 13 weeks old. Two reports failed to describe the rodent age [14], [16] and one to inform on gender and age [24].…”

“…The literature search also identified 16 reports dealing with interventions which potentially impact the bone micro-architecture and the bone healing or regeneration, with 6 studies applying to the maxilla [3], [4], [8], [15], [16], [23], 6 to the mandible [3], [11], [32], [40], [41], [43] and 4 to the condyle region [10], [22], [28], [46]. It is evident that the control groups included in these studies offer the possibility to extract bone micro-architectural parameters that characterize the physiological bone micro-architectural state.…”