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Title Supplemental Parathyroid Hormone Increases Bone Formation Around Dental Implants in an Osteoporotic Animal Model
Clinical Question Does parathyroid hormone (PTH) supplementation improve the osseointegration of dental implants in adult patients?
Clinical Bottom Line In animal models, PTH supplementation improves new bone formation around dental implants. This conclusion is based on animal studies only; clinical trials are needed to assess the effect of parathyroid hormone supplements on dental implants.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 26689569Javed/201618 Animal studies Systematic review of preclinical animal studies
Key resultsDatabases were searched from 1965-2015; 18 studies fulfilled the eligibility criteria. Evidence was limited to preclinical animal studies only (11 studies in rodents, 4 in dogs and 3 in rabbits). Number of titanium implants placed ranged between 20 and 80 implants. Results from 16 studies showed that PTH supplementation enhanced new bone formation and/or bone-implant contact (BIC), around implants. One study suggests that PTH-coated implants improve BIC and BA. One study showed no significant difference in BIC and new bone formation around implants with PTH hydrogel placement.
#2) 27349546Oki/2016Animal study (10 female rabbits)Laboratory study
Key resultsOne group of rabbits was given PTH by subcutaneous injection for 4 weeks (PTH-group) and the control group was given saline injections for 4 weeks (Osteoporosis; OP-group). Implants were inserted into the distal femoral epiphyses of each animal and insertion torque (IT) and implant stability quotient (ISQ) were measured. Histological examination showed newly formed trabecular bone around the implant in the PTH-group but not in the OP-group. The trabecular bone structures in the PTH-group appeared thicker than those in the OP-group. In the PTH-group, the mean IT value was significantly greater than in the OP-group (29.8 ± 6.2 Ncm and 10.0 ± 2.1 Ncm, respectively; P < 0.05). The ISQ value in the PTH-group was significantly higher than that in the OP-group (74.7 ± 11.2 and 55.9 ± 13.5, respectively; P < 0.05). The investigators concluded that "intermittent PTH administration could be an effective treatment for achieving favorable primary stability of dental implants in patients with osteoporosis."
#3) 26513040Heo/201627 female Sprague-Dawley ratsLaboratory study
Key results27 female Sprague-Dawley rats were divided into 3 groups (n = 9) and were ovariectomized (OVX). After 8 weeks the upper right molar was extracted. An implant was placed 4 weeks after extraction. The PTH group received PTH, and the OVX group and the control group received vehicle only. After implant placement, 30 μg/kg of PTH was subcutaneously administered in 3 times a week. Three rats in each group were killed at 1, 2, and 4 weeks for histological examination. After 4 weeks, the amount of newly formed bone around implants in PTH was comparable with the control group; however, the OVX group displayed relatively little new bone. The investigators concluded that "intermittent PTH has the potential to increase new bone formation around implant."
Evidence Search (("Parathyroid"[Mesh]) AND " osseointegration "[Mesh])AND " Implants"[Mesh]))
Comments on
The Evidence
Javed/2016 is a systemic review with a comprehensive, detailed, and relevant search. Individual studies were assessed for validity. In total, 18 studies were selected and a systematic review was done on the data collected. Of the trials that were selected and analyzed, different techniques and doses of parathyroid hormone were used, so parameters could not be directly compared in different experimental models. The effect of the implant surface, whether machined or roughed, was not tested, even though all implants were placed in hard bone (tibiae, humerus, calvaria, and mandible). None of the articles reported any adverse effects associated with systemic PTH administration. A study in rats by Vahle et al. reported that daily administration of PTH at a dosage of 75 μg/ kg/day for 24 months resulted in a mean incidence (21 to 31 %) of osteosarcoma. These findings should be taken in consideration in a future protocol for the clinical use of PTH in implantology, including low doses and short-term administration periods. The Oka/2016 and Heo/2016 studies used rabbits and rats respectively. The groups were similar at the start and were treated equally other than the intervention. In the Oka study, corticosteroids were used to induce osteoporosis. There was more new dense bone formation at the histological level for both studies in the PTH than the control group. There did not seem to be any competing interests exhibited in any of the three articles. Within the limits of the present studies, the effects of PTH delivery in osseointegration remain debatable, and further randomized control trials are needed.
Applicability The use of parathyroid hormone as a systemic supplement or as a surface coating for dental implants shows promise as an option to enhance new bone formation especially for patients with osteoporosis, as it shows significant positive effects on osseointegration. Thus far, studies and reviews are limited to animal studies, and clinical trials are needed to better assess the clinical performance of parathyroid hormone supplements on dental implants.
Specialty/Discipline (Oral Surgery) (Periodontics) (Prosthodontics)
Keywords Parathyroid hormone, osseointegration, implants
ID# 3284
Date of submission: 11/14/2017spacer
E-mail almojel@uthscsa.edu
Author Neda Almojel
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