A COMPREHENSIVE REVIEW OF SYSTEMIC FACTORS ASSOCIATED WITH PERI-IMPLANT DISEASES
Review Article
52, 54, 55
mediators. Underlying causes of osteoporosis include pre- and postmenopausal estrogen deficiency, excessive glucocorticoid intake, eating disorders such as anorexia nervosa and celiac disease. 56, 57 Although the bone quality and strength are compromised in osteoporotic patients; osteoporosis is not considered a contraindication for implant therapy. 58, 59 In a recent systematic review, Javed et al. 60 assessed the effect of osteogenic coatings on the osseointegration of implants under induced osteoporotic conditions. Nearly 80 % studies reported that osteogenic coatings around implant surfaces enhance bone formation, bone-toimplant contact( BIC) and bone volume( BV) under osteoporosis-like conditions. This could possibly be accredited to the increase in surface roughness of the implant caused by osteogenic coatings, which facilitate the attachment of osteoprogenitor cells to the implant surface. Holahan et al. 59 conducted a retrospective study to evaluate whether a diagnosis of osteoporosis affected the survival rate of osseointegrated dental implants. In this study 59, a total of 3,224 implants placed in 746 female patients aged at least 50 years old at the time of implant placement were assessed. The results showed that patients with a diagnosis of osteoporosis or osteopenia were not significantly more likely to develop implant failure compared to those without such a diagnosis. 59 Krennmair et al. 61 evaluated the implant treatment outcomes for patients suffering from autoimmune rheumatoid arthritis( RA) with or without concomitant connective tissue diseases( CTD). In this study, 61 34 female patients( 25 isolated RA; nine RA + CTD) were included. At the mean duration of follow-up of nearly 46 month, all implants presented a survival rate of 100 %. In isolated RA patients, acceptable marginal bone loss( MBL)( mean: 2.1 mm; SD: 0.5 mm), pocket depth( mean: 2.8 mm; SD: 3.2 mm) and healthy soft-tissue conditions( plaque / bleeding / gingiva index Grade 0 in 80 %) were observed. 61 Results from a case-series report, 62 showed a high implant survival rate during follow-up with a cumulative 3-year implant success rate of 96.1 %. In this study, RA patients demonstrated acceptable MBL( mean: 2.1 +/- 0.5 mm) and satisfactory soft tissue conditions; whereas CTD patients showed increased MBL( mean: 3.1 +/- 0.7 mm). The study 62 concluded that a high implant and prosthodontic success rate can be anticipated in patients suffering from RA; however, the authors emphasized that optimal oral hygiene assists in ensuring stable long-term survival of dental implants in patients with RA. 62 3.4. Irradiation Osteoradionecrosis is usually observed several years following radiotherapy and is associated with local trauma within the hypovascular – hypocellular hypoxic tissues( that occurs as a result of radiationinduced endarteritris). 63 In this regard, the interval between the end of cancer therapy and placement of dental implants may contribute to the success or failure of osseointegration. Studies 64-66 have investigated the required time interval between radiotherapy and implant installation that may influence osseointegration; however the results remain debatable. In a systematic review, Zen Filho et al. 67 assessed the safety of dental implants placed in irradiated bone and to discuss their viability when placed post-radiotherapy. Eight publications were assessed in this systematic review 67 and the results showed a total of 331 patients received 1237 implants. The time interval between irradiation and dental implantation ranged from 6 to 15 months. The overall implant failure rate of 9.53 % and osseointegration success rates ranged between 62.5 % and 100 %. 67 In another review, Javed et al. 20 assessed the implant survival rate after oral cancer therapy. In total, 21 studies were included in this review out of which, 16 studies reported that dental implants can osseointegrate and remain functionally stable in patients having undergone radiotherapy following oral cancer surgery. 20 The authors concluded that dental implants can osseointegrate and remain functionally stable in patients having undergone oral cancer treatment. 20 3.5. Human immunodeficiency virus infection Human immunodeficiency virus( HIV) infection is characterized by progressive immune system failure that gives rise to the development of opportunistic infections and neoplasms. The virus invades CD4 + T lymphocytes, macrophages and dendritic cells, and the CD4 + T cell counts gradually decrease as a result of direct cytopathic action or cytotoxic CD8 + T lymphocyte-mediated attack. In a recent systematic review, Ata-Ali et al. 68 attempted to answer the following focused question“ does HIV infection have an impact upon dental implant osseointegration?” The combinations of search terms resulted in a list of 132 titles. Consequently, 101 studies were excluded on the basis of the evaluation of the title and abstract, thereby leaving 9 articles for eligibility assessment. Amongst the studies included in this systematic review, a total of 173 dental implants were placed in 80 patients( 135 implants in 56 HIV-positive individuals and 38 implants in 24 HIV-negative patients-control groups). A single loss of dental implant osseointegration was recorded in an HIV-positive patient. 68 In the study by Stevenson et al. 69, 40 dental implants were placed in 20 HIV-infected patients. No implant osseointegration failures were recorded after 6 months of follow-up. Similarly, in another study of 39 dental implants placed in 24 HIV-infected patients, no implant osseointegration failures were recorded after 12 months of followup. 70 Should dental implants placed in HIV positive patients sustain bone levels in the long-term( 5 years or longer) requires further investigations. 3.6. Genetic factors Jacobi-Gresser et al. 71 assessed diagnostic markers to predict titanium implant failure. The study reported that tumor necrosis factor-
42 Stoma Edu J. 2017; 4( 1): 39-45. http:// www. stomaeduj. com