Chapter 1 Implant research update
With so much interest in dental implants around the world there is an enormous amount of research being reported into a wide range of topics. Here, Stephen Hancocks describes some of the most recent studies scanned from the literature and looks particularly at current thinking on bisphosphonates and implants. There has been considerable debate about the use of the class of drugs called bisphosphonates (BP) for some years now especially in relation to their propensity to mediate BP-related osteonecrosis of the jaws (BRONJ). The drugs are prescribed to help treat conditions in which there are disturbances of bone growth such as osteoporosis, osteitis deformans (Paget’s disease), bone metastasis from cancers and other conditions involving fragile, breakable bone. They work by inhibiting the digestion of bone by causing osteoclasts to undergo cell death, thereby slowing bone loss and undermining the usual homeostatic body balance of osteoblast and osteoclast activity which keeps bone in constant turnover. This has an obvious relevance to implant treatment which relies on continuing healthy bone metabolism and growth for implants to undergo successful osseointegration. Risk factors for developing osteonecrosis of the jaw that should be considered are: potency of bisphosphonate (this is highest for the drug zoledronate), route of administration – oral or intravenous, cumulative dose, duration and type of malignant disease, concomitant treatment, smoking and history of dental disease. NICE recommends that all patients should have a dental check-up (and any necessary remedial work should be performed) before bisphosphonate treatment, or as soon as possible after starting treatment. Patients should also maintain good oral hygiene, receive routine dental check-ups, and report any oral symptoms such as dental mobility, pain, or swelling, non-healing sores or discharge during treatment. Because of this, there has been disagreement as to whether it is safe to place implants in patients under BP therapy owing to the risk of developing BRONJ. For example The American Association of Oral and Maxillofacial Surgeons recommends that dental implants should be avoided in oncologic patients treated with intravenous BPs. Conversely, for patients receiving oral BPs, dental implant placement is not explicitly contraindicated even if a cautious approach is suggested.
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One recent study1 aimed to assess the risk level as related to adverse events such as implant failure and BRONJ in a large cohort of osteoporotic patients who had implant placement and concomitant application of plasma rich growth factor (PGRF)-Endoret. The clinical charts of 235 middle-aged women under oral BP therapy for osteoporosis, who underwent placement of 1,267 dental implants, were reviewed. In order to attempt to improve osseointegration the implants were always placed in association with the growth factor. Over the 10 year follow-up period 16 implants were lost in 16 patients giving a survival rate of 98.7% and 93.2% on an implant basis and patient basis, respectively. No cases of BRONJ were reported and the authors concluded that their results supported the current literature that the risk for developing BRONJ associated to dental implant surgery remains low for patients receiving oral BPs. Meanwhile in another comparative, prospective study2, 24 female patients, aged >54 years, were chosen, all with partially edentulous mandibles. Group A consisted of 12 patients with osteoporosis taking the BP zoledronic acid receiving a onceyearly intravenous infusion (5 mg). Control group B consisted of 12 similar patients without osteoporosis but not taking drugs. In both groups, the remaining teeth were extracted before 120 implants, 3.7-mm wide and 16-mm long, were immediately placed in the interforaminal region of the mandibles. The 1-year implant survival rate was 100%. No apparent necrotic bone was observed among the patients receiving BP after implant surgery. Once again this encouraged the authors to conclude that immediate implant osseointegration can be successful in patients with osteoporosis using bisphosphonates, suggesting the safety of implantology as a treatment modality. One of the often quoted facts about modern medicine and dentistry is that the ageing population experiences complex medical histories and is often subject to poly-pharmacy. So, given the potential risk of BRONJ, how much of a benefit are dental implants to those patients taking BP? Research in the USA3 compared the quality of life (QoL) in partially edentulous osteoporotic women who had missing teeth restored with dental implant retained restorations with those who did not and also reported the rate of osteonecrosis in the sample. The 237 participants completed a 23-question document enquiring across psychosocial domains of well-being including occupational, health, emotional, and sexual domains which together contributed to an overall score. The subset of participants having dental implant supported prosthesis (64) was compared to the subset having nonimplant supported fixed restorations (47), the subset having non-implant supported removable restorations (60), and the subset having no restoration of missing teeth (66). Results showed a significant difference in all QoL domains between the four
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subsets. While 134 participants reported oral bisphosphonate and 51 reported intravenous bisphosphonate use, no signs of BRONJ were identified. The findings show implant retained oral rehabilitation has a statistically significant positive impact over nonimplant and traditional fixed restorations, removable restorations, and no restoration of missing teeth for these participants. Overall, while continuing and further research is needed, the message seems to be that with awareness of all parties concerned and with due care and consultation the placement of dental implants in patients undergoing BP therapy, especially oral therapy is safe and of benefit. References 1.
Mozzati M et al. Failure risk estimates after dental implants placement
associated with plasma rich in growth factor-Endoret in osteoporotic women
under bisphosphonate therapy. J Craniofacial Surg 2015; 26: 749-755.
2.
Siebert T et al. Immediate implant placement in a patient with osteoporosis
undergoing bisphosphonate therapy: 1-year preliminary prospective study. J
Oral Implantol 2015; 41 Spec No: 360-365.
3.
DeBaz C et al. Dental implant supported restorations improve quality of life in
osteoporotic women. Int J Dentistry 2015; 45: 1923.
Recommended further reading Guidance for dentists in primary care is included in Oral Health Management of Patients Prescribed Bisphosphonates: Dental Clinical Guidance, Scottish Dental Clinical Effectiveness Programme, April 2011 (available at www.sdcep.org.uk)
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