Article in Compendium of continuing education in dentistry (Jamesburg, N. J.: 995) · October 2011 Source: PubMed citations 46 reads 3,359 authors: Some of the authors of this publication are also working on these related projects
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| Long-Term Implant Survivability
Based on long-term implant studies, numerous investigators con- cluded that there was little or no difference in the survival rate for implants surrounded by oral mucosa or KG. 36-40 These data pertain to smooth-surfaced implants and screw-retained prostheses. On the other hand, two investigations demonstrated there was a lower implant survival rate when keratinized tissue was absent around textured-surfaced implants. This occurred around hydroxyapa- tite (HA)-coated implants 41 and IMZ plasma-sprayed implants. 42
However, confounding variables include the fact that HA-coated implants may manifest a lower long-term survival rate than non- coated implants 43-45 and plasma-sprayed implants have been re- placed with sandblasted/acid-etched (SLA)-surfaced implants. 46,47
Currently, textured-surfaced implants are employed. In this regard, Abrahamsson et al 48 reported that the histological attach- ment of the tissue (JE and connective tissue) adjacent to an im- plant was consistent irrespective of the type of implant or surface roughness. 49 However, they also indicated that plaque control was easier on smooth-surfaced implants compared to textured sur- faces.
48 Therefore, the following question arises: If it is harder to cleanse textured surfaces than smooth surfaces and most of the above survival data pertains to smooth surfaces, is it appropriate to extrapolate the above findings to textured surfaces? To definitively answer that question, additional long-term studies are needed to assess whether textured-surfaced implants will manifest high survival rates over a long period of time despite a dearth of KG. Plaque Index Three studies reported a higher plaque index (PI) around im- plants associated with < 2 mm of KG compared to > 2 mm KG (Ta- ble 2).
4,10,50 Ostensibly, this was due to the tissues being movable or they were more tender to brush, so sites were avoided during oral hygiene. Others did not corroborate these findings. 28,50-52 Schrott et al 50
buccal when both sides manifested a dearth of keratinized tissue. Inflammation It was suggested that KG tissue is more protective than mucosa and inhibits an inflammatory alteration in the connective tissue around implants. 48 In this regard, when there was a dearth of ke- ratinized tissue (< 2 mm), several investigators reported there was a statistically significant increase in the amount of inflammation (GI or percentage of sites manifesting bleeding upon probing) compared to sites with > 2 mm KG (Figure 3) (Table 2). 4,11,53 Oth-
ers reported the amount of inflammation was not increased when there was a lack of KG (Figure 4). 28,51,52
Some researchers found that the absence of KG was associated with a statistically significant increased amount of recession Fig 4.
Fig 6. Fig 7.
Fig 3. Fig 5.
Fig 3. Some sites without keratinized gingiva, such as Nos. 7 and 10, manifest an increased amount of inflammation in response to plaque compared to other locations with keratinized gingiva (eg, site Nos. 5 and 12). Fig 4. In the absence of attached gingiva, tissue adjacent to an implant can remain healthy (site No. 12). Fig 5. Absence of attached gingiva predisposes some patients to progressive recession (site No. 4). Fig 6 and Fig 7. Absence of keratinized tissue often does not result in additional recession. Site No. 24 demonstrates recession at time of crown insertion (Fig 6). Fig 7 demonstrates that the tissue level has remained stable after 1 year. This patient had good oral hygiene.
by Block et al 41
were determined on HA-coated dental implants, which were prone to bone loss and failure. the rOLe OF Kg arOunD iMpLants suppOrting OverDentures Adibrad et al 56 reported that when implants supporting an overden- ture with < 2 mm KG surrounding them were compared to implants with > 2 mm KG, sites with < 2 mm of keratinized tissue were as- sociated with higher plaque accumulation, gingival inflammation, bleeding upon probing, and mucosal recession. It was speculated that the flange of overdentures may favor plaque accumulation and mucosal irritation. 56 In contrast, Heckman et al 57 noted no signifi- cant difference was found between bleeding scores at sites with and without KG under an overdenture. Similarly, Kaptein et al 58
implants with respect to the width of KG under overdentures. Oth- ers also found there was no detrimental effect around implants that supported overdentures if there was a lack of KG. 40,59-61
DiscussiOn It was anticipated that a comprehensive inspection of the litera- ture would provide an unambiguous answer to the question of whether or not KG around dental implants is necessary to main- tain peri-implant health. However, the literature provided con- tradictions with respect to every facet of this review, which pre- cludes drawing definitive conclusions. In addition, the literature pertaining to dental implants failed to provide any clarity as to how much KG is necessary to maintain health. It appears there may be circumstances where it is beneficial to have keratinized tissue around implants in humans (Figure 5) (Table 2), 50,51,53
but this finding conflicted with data of others (Figure 6 and Figure 7). 28,54
52 found a weak correlation between the amount of KG and recession. In addition, it should be noted that in the study by Schrott et al 50 the standard deviation around the means was greater than the mean data, which raises questions as to the accuracy of these findings regarding recession (for < 2 mm vs. > 2 mm KG, recession was, respectively, 0.69 +/- 1.11 mm vs. 0.08 +/- 0.86 mm). Furthermore, it needs to be noted that a lack of attached gingiva may not be the precipitating factor for ongoing deterioration of a site, but rather a consequence of recession. Yüklə 0,61 Mb. Dostları ilə paylaş:
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