IM0210

implants2_2010 In addition, some studies have shown that certain designs in the geometry of implant coro- nal part may contribute to bone loss, while other studieshaveindicatedthatsuchbonelosscanbe prevented by incorporating a biomechanical stable connection and a more retentive surface on the implant collar.11, 12 Prevention of horizontal and vertical mar- ginal peri-implant bone resorption during the post-loadingperiodisfundamentalinmaintain- ing stable gingival levels around implant-sup- ported restorations.13 It has been demonstrated that peri-implant marginal bone loss is time-re- lated with significantly more acute bone loss during the preloading period than in the follow- ing loading phases (two years after surgery) and also during the first year after loading (six months to one year after surgery) than in the secondone (oneyeartotwoyearsaftersurgery). Aesthetic outcomes cannot be attributed to a single parameter. They are the result of a number of important factors, especially in the aesthetic area. Both biologic width and the integration of platform switching concept are of utmost sig- nificance in preserving a stable marginal bone level around implant neck. It is important to un- derstand mainly the meaning of biologic width. Hence, the stable bone serves as a support for the soft tissue determining the long-term aes- thetic and functional treatment, the outcome stability being ensured in this manner. The following points should be noted: _ The use of a single post for temporary and final prosthetic work; _ As long as the frequent replacement of parts is not avoided, repeated destruction of the con- nective-tissue attachment of the biologic width occurs increasing the risk of bone re- sorption; _A special implant and abutment design (a ledge and integration of the biologic width/tapered shape of the post) facilitates nonsurgical lengtheningandthickeningoftheperi-implant soft tissue. This leads to the establishment of a wider and more resistant zone of connective tissue. A mi- cro-rough and nano-rough titanium surface ex- tending to the implant shoulder in conjunction with the platform switching concept provides osseous integration along the entire length of the implant. A fine thread optimally distributes the masti- catory forces in the region of the implant neck, avoiding further bone loss in this region.15 Possible interactions amongst factors con- tributing to peri - implant bone loss. These factors include: _Surgical and anatomical considerations such as mucoperiosteal flap design, thickness of buccal and lingual cortical plates of bone re- maining after osteotomy preparation, bone quality, healing technique submerged or non- submerged, early unintentional cover screw exposure by mucosal dehiscence and amount of keratinized Gingiva; _Patient risk factors such as medical and phar- macological status, habits including cigarette smoking, poor oral hygiene, excessive alcohol consumption, mucosal erosive pathology like lichen planus, previous or present periodontitis (chronic or aggressive); _Biologic width related factors such as level of the micro-gap, platform switching and im- plant-tooth or implant-implant distance; _Implant design including geometry, surface, length and diameter; _Biomechanical factors including time of load- ing, type of loading, type of prosthesis, habits like bruxism. Flap design It was reported in the literature long time ago32 that, whenever a mucoperiosteal flap is re- flected about a tooth, some crestal bone resorp- tion will occur. Similarly elevating a flap to place adentalimplantwillleadtocrestalbonelossand there is evidence suggesting a direct relation- ship between size of full thickness flap and the resulting post op bone loss. Other studies33 reported no statistically sig- nificant differences using more traditional his- tologicalevaluationofretrievedspecimensafter twelve weeks of site healing. Becker reported the same magnitude of difference in buccal vertical