Effect of PTH and corticotomy on implant movement under mechanical force

Abstract

Background Osseointegrated implants are considered as clinically non-movable. Parathyroid hormone (PTH) is known to play a significant role in the regulation of bone remodeling and in intermittent, low doses, result in osteoanabolic effects. This study aimed to investigate the effects of PTH and corticotomy, both under traction force, on osseointegrated implants. Methods Four implants—two in each hemimandible—were placed in each of the three study mongrels. Each mongrels were designated as control, normal dose PTH (PTH-1), and high dose PTH (PTH-2) groups, with each groups further subdivided into non-surgery implant and surgery implant. After osseointegration, mechanical force with NiTi closed coil springs (500 g) was applied around each implants. Corticotomy was performed around one of four implants in each mongrels. Parathyroid hormone was administered locally on a weekly basis for 20 weeks. Clinical movement of the implants were evaluated with the superimposed 3D- scanned data, bone- microarchitectural and histologic examinations. Results Superimposition analysis showed continuous movement of the non-surgery implant of PTH-1 group. Movement was further justified with lowest bone implant contact (adjusted BIC; 44.77%) in histomorphometric analysis. Upregulation of bone remodeling around the implant was observed in the normal dose PTH group. In the surgery implants, the remarkably higher adjusted BIC compared to the non-surgery implants indicated increased bone formation around the implant surface. Conclusion The results indicate that the catabolic and anabolic balance of osseointegrated implants in terms of bone remodeling can be shifted via various interventions including pharmacological, surgical and mechanical force. Clinical relevance Upregulated bone remodeling by PTH and corticotomy under continuous mechanical force showed the possible implications for the movement of osseointegrated dental implant.

Role of hormones in bone remodeling in the craniofacial complex: A review

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Fig. 2 Hormones related to bone formation and resorption.

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“…A study on mongrels found increased levels of bone remodeling around dental implants inserted in the mandible, in the group administered PTH. 25 An application perhaps close to clinical utilization is presented in a paper investigating PTH-coated titanium dental implants in rats. 105 The results were promising, with increased bone formation around the PTH-coated implants.…”

Dental implant considerations in patients with systemic diseases: An updated comprehensive review

“…74 PTH-induced bone remodelling upregulation and corticotomy in dental implant site preparation with additional functional forces may impose a risk on the displacement of an osseointegrated implant. The study by Kim et al 75 demonstrated that various procedures, such as surgical, pharmacological and application of functional forces, might alter the catabolic and anabolic balance of osseointegrated implants in bone remodelling.…”