The effects of intro-oral parathyroid hormone on the healing of tooth extraction socket: an experimental study on hyperglycemic rats

Abstract

The effects of intro-oral parathyroid hormone on the healing of tooth extraction socket: an experimental study on hyperglycemic rats Objective: To investigate the effects of intro-oral injection of parathyroid hormone (PTH) on tooth extraction wound healing in hyperglycemic rats.Methodology: 60 male Sprague-Dawley rats were randomly divided into the normal group (n=30) and DM group (n=30). Type 1 diabetes mellitus (DM) was induced by streptozotocin. After extracting the left first molar of all rats, each group was further divided into 3 subgroups (n=10 per subgroup), receiving the administration of intermittent PTH, continuous PTH and saline (control), respectively. The intermittent-PTH group received intra-oral injection of PTH three times per week for two weeks. A thermosensitive controlled-release hydrogel was synthesized for continuous-PTH administration. The serum chemistry was determined to evaluate the systemic condition. All animals were sacrificed after 14 days. Micro-computed tomography (Micro-CT) and histological analyses were used to evaluate the healing of extraction sockets.Results: The level of serum glucose in the DM groups was significantly higher than that in the non-DM groups (p<0.05); the level of serum calcium was similar in all groups (p>0.05). Micro-CT analysis showed that the DM group had a significantly lower alveolar bone trabecular number (Tb.N) and higher trabecular separation (Tb.Sp) than the normal group (p<0.05). The histological analyses showed that no significant difference in the amount of new bone (hard tissue) formation was found between the PTH and non-PTH groups (p>0.05).Conclusions: Bone formation in the extraction socket of the type 1 diabetic rats was reduced. PTH did not improve the healing of hard and soft tissues.The different PTH administration regimes (continuous vs. intermittent) had similar effect on tissue healing. These results demonstrated that the metabolic characteristics of the hyperglycemic rats produced a condition that was unable to respond to PTH treatment.

The evaluation of the effects of natural zeolite (Clinoptilolite) in diabetic rats on bone healing in dental extracting socket

“… 7 reported that 30 days after tooth extraction in rats, socket outlines were invisible on the radiograph. Xu L. et al 8 reported that bone formation with sufficient radio-opacity was achieved in the socket within 14 days. Similar to the literature, we observed radiologically the bone formation in the socket on the 14th and 28th days.…”

“…Pitol Palin L. et al 11 showed that diabetes stimulates the inflammatory process in the first stage of the alveolar repair process 7 days after tooth extraction, which leads to disruption of the mineralization process and collagen fiber organization and a decrease in fiber count. Xu L. et al 8 showed in their study with 14-day follow-up that vascular endothelial cell function, osteoblastic function and matrix mineralization were impaired due to the increased inflammatory response due to high glucose levels, resulting in delayed healing of tooth extraction sockets.…”

Pathogenesis and treatment of wound healing in patients with diabetes after tooth extraction

“…PTH has been shown to reduce the alveolar bone loss in the intermittent and systemic administrations by decreasing the RANKL/OPG ratio in diabetic rats (119). However, some studies found that PTH did not improve the post-extraction wound healing or stimulate the osseointegration in hyperglycemic rats, regardless of administration of PTH (intermittent versus continuous) (120). This can be explained by the overall inhibitory effect of high levels of AGEs and collagen cross-linking on bone formation under diabetic metabolism (121).…”

Parathyroid Hormone 1 Receptor Signaling in Dental Mesenchymal Stem Cells: Basic and Clinical Implications

“…In comparison with bisphosphonates, PTH has a better therapeutic effect in both hard and soft tissue regeneration at the extraction site by enhancing osteogenesis and collagen deposition while suppressing inflammation ( Kuroshima et al, 2014b ). However, PTH did not have a significant effect on extraction wound healing in hyperglycemic rats ( Xu et al, 2020 ). Another study also demonstrated that PTH did not benefit the healing process of the bone-implant interface in diabetic rats ( Rybaczek et al, 2015 ).…”