A COMPREHENSIVE REVIEW OF THE LOCAL RISK-FACTORS ASSOCIATED WITH THE ETIOLOGY OF PERI-IMPLANT DISEASES
3. Results Local risk-factors associated with the etiology of peri-implant diseases are summarized in Figure 2. 3.1. Bone quality Studies have reported that peri-implant bone loss is more often manifested in the maxilla, which is composed of less dense bone as compared to the mandible. It has also been suggested that compromised bone density is the most critical factor associated with peri-implant bone loss 25; whereas others suggest that both poor bone density and volume are associated with the etiology of peri-implant diseases and bone loss 26-27. 3.2. Poor oral hygiene Studies from human biopsies 28, 29 have shown that peri-implantitis and periodontitis lesions have several features in common. One of such features is poor oral hygiene maintenance. The dental plaque is the core etiological factor that causes the development of oral biofilm around the teeth and dental implant surfaces 30-34. In the study by Serino and Ström 35, most of the implants with a diagnosis of peri-implantitis were associated with no accessibility and / or capability for appropriate oral hygiene measures. This study 35 concluded that oral hygiene at the implant sites is most likely associated with the presence or absence of peri-implantitis. Moreover, studies 36-42 have also reported that microbes residing in the oral biofilm such as Aggregatibacter actinomycetemcomitans, Enterococcus fecalis, Porphyromonas gingivalis, and Staphylococcus aureus( which are also associated with the etiology of periodontitis) play a role in the initiation of peri-implantitis. It is therefore predictable to find a significant relationship between peri-implant bone loss and poor oral hygiene. In this regard, it is imperative for oral healthcare providers to educate patients regarding the significance of regular oral hygiene maintenance and routine dental checkups towards the establishment of peri-implant and periodontal maintenance.
Figure 1. A diagrammatic presentation of the local risk factors associated with the etiology of peri-implant diseases
3.3. History of periodontitis It has been claimed that peri-implantitis is a common finding in patients with a history of periodontitis 43-44. Results from a systematic review and meta-analysis showed that the relative risk for peri-implantitis was significantly higher in patients with a previous history of periodontitis compared to peri-implantitis patients without a history of periodontal disease 43. However, in a recent study, Meyle et al. 45 investigated the longterm clinical and radiographic parameters of osseointegrated implants in non-smoking patients with a previous history of chronic periodontitis. The results showed that patients with a previous history of periodontitis regularly attending an oral hygiene maintenance program displayed implant survival rates up to 100 % after 5 and 10 years. Similarly, in a systematic review, Pesce et al. 46 concluded that there is a lack of consensus regarding the role of periodontitis in the etiology of peri-implantitis. Nevertheless, since several periodontopathogens( such as Aggregatibacter actinomycetemcomitans, Prevotella intermedia and Porphyromonas gingivalis) associated with the etiology of periodontitis have also been isolated from peri-implant sulci of patients with periimplantitis 47-50. In a recent study, Jorand et al. 30 reported that Desulfovibrio fairfieldensis is one of the most relevant sulphate-reducing bacteria of the human oral cavity suspected to be involved in peri-implantitis and implant corrosion. It is arduous to disregard the hypothesis that peri-implantitis is more common in patients with a history of periodontitis. 3.4. Smoking It is well-established that periodontal inflammation and marginal bone loss are more often manifested in tobacco smokers as compared to individuals not using tobacco in any form 51-54 12, 55-57
. Studies have also reported that cigarette smokers are more susceptible to develop peri-implantitis as
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