implants - internationalmagazine of oral implantology

clinical study _ flapless implant surgery I Fig. 11_Peri-implant soft tissue with restoration inserted. Fig. 12_Peri-implant soft tissue with restoration inserted (Thommen Element). I 15implants4_2011 control group the implants with less than 2 mm of AG had significantly increased BOP frequency. In addition, radiographic examination showed a higher average bone loss when AG was not suffi- cient. These results however have to be viewed with caution: Meijer et al. (1992) stated that the resolu- tion of conventional X-ray is limited and minimal changes in the marginal bone will often not be recognised. This was confirmed in an animal experi- ment(Caulieretal.1997).Current3-Dimagingtech- niques such as CT or DVT (digital volume tomogra- phy) offer an improved picture of the peri-implant bone quality (Mengel et al. 2006). However, legal considerations prohibit a more frequent X-ray fol- low-up. In a study of 26 patients, Krekeler et al. (1983) found that the presence of AG improved gingiva’s sensitivitytoinflammationcausedbymechanicalir- ritation.ItseemsthereforelikelythatAGisadvanta- geousforthehealthoftheperi-implanttissuebutit is not a prerequisite condition. According to the au- thors,plaquecontrolisthemostimportantfactorfor theabsenceofperi-implantinflammation.Afurther study provided contradictory results. This clinical study found a correlation between AG and the inci- dence of mucositis (Roo-Jansaker et al. 2006). The authors reasoned that implants without keratinised tissue have a tendency to gingiva recession and therefore less peri-implant pockets will be found. ThiswasconfirmedbyChungetal.(2006)inaretro- spective multicentre study of 69 patients with 339 implants.Inthisstudy,theappearanceofplaqueand peri-implant lesions was significantly increased around implants with AG. Unfortunately, this was not confirmed in further clinical studies. It was shownthatneitherthepresenceorthewidthofker- atinised mucosa, nor the mucosal border mobility hadaninfluenceonplaquecontrolorontheinflam- matory status of the peri-implant tissue (Block etal. 1990; Strub et al. 1991; Wennström et al. 1994; Hanisch et al. 1997; Cairo et al. 2008). According to Wennström et al. (1994), there was no negative ef- fect of keratinised tissue on bleeding behaviour or plaque control, although 61% of the implants showed no peri-implant AG. Thelatterfindingsareinlinewiththeresultspre- sented in this article. Of the 346 implants, 244 were surrounded by keratinised tissue. Our findings con- firmed that less BOP is found in the presence of AG. This is independent of the implant type used (zirco- nium-oxide or titanium) and design (one or two piece).Wethereforeconcludethatinthepresenceof keratinised alveolar mucosa, susceptibility to peri- implant inflammation is reduced. This was also the conclusion of a recent multicentre study (Eccelente etal.2010),butthefindingmustbetreatedwithcau- tion. Recently, it was also demonstrated histologi- cally that peri-implant inflammation can be found even in the absence of clinical signs (Nahas et al. 2010). In a human study, the authors investigated 12samplesobtainedatimplantuncovering(second- stage surgery). The presence of chronic, inflamed peri-implantinfiltrateswasshownintheabsenceof clinical symptoms. In this study, only 26.2% of Straumann and 31.9%ofThommenimplantsdisplayedBOP(thedif- ference was not significant). Only one of the eight Z-SystemsimplantswasBOPpositive.Noconclusion ispossiblebasedonthissmallnumberofimplants.It seems likely nevertheless that the soft-tissue inte- grationofzirconium-oxideimplantsisasgood,ifnot better, as suggested by Blaschke and Volz (2006). It is know that AG has a positive impact on peri- implant health (Krekeler et al. 1983; Warrer et al. 1995; Bouri et al. 2008; Adibrad et al. 2009). In a meta-analysis of the role of local risk factors in im- plantology, no relationship was found between the presence of keratinised mucosa and implant sur- vival (Martin et al. 2009). Our results demonstrate that the presence of keratinised gingiva around im- plants may lead to less peri-implant inflammation and has no immediate effect on implant survival. Fig. 11 Fig. 12