Comparison of clinical, radiographic and immunological parameters of teeth and different dental implant platforms

Comparison of two different techniques used for the maintenance of peri-implant soft tissue health: a pilot randomized clinical trial

OBJECTIVES

The aim of this pilot study was to compare the effectiveness of two different methods of debridement on maintaining and improving peri-implant soft tissue health over a period of 12 months.

MATERIALS AND METHODS

Twenty adult patients (25 implants) were enrolled in a randomized, single-blinded, parallel group clinical trial. All implants included showed no signs of pathologic bone loss. Patients were scheduled to be reviewed every 3 months over a 12 months period. Nine patients (15 implants) were randomly allocated to a test group and treated with a low abrasive air polishing powder (Air-Flow^® Perio, EMS) (AFP) and another nine (10 implants) to a control group and treated with titanium curettes (TC). Peri-implant crevicular fluid samples were analyzed to quantitatively measure the concentration of six interleukins (IL-6, IL-8, IL-1β, TNF, IL-10 and IL-12). A multilevel analysis was used to test the comparison between the two treatments. The same analysis was used to study the relationship between clinical parameters and cytokines while controlling for confounding factors.

RESULTS

There was no significant difference in bleeding on probing (BOP) between the two treatment methods (p = .35). Both debridement techniques resulted in a similar reduction of BOP (40.04% and 39.93%). IL-6 was the only cytokine of the six investigated that demonstrated a correlation with a clinical parameter (BOP) (p = .05).

CONCLUSIONS

Both treatment methods were proven to be effective in reducing peri-implant inflammation and preventing further disease progression. Some cytokines may act as markers for peri-implant disease as the present study showed a significant relationship between IL-6 and BOP.

Periodontal parameters around implants and natural teeth

INTRODUCTION

Nowadays, dental implants permit consideration of as one of the most reliable therapeutic modalities during the establishment of any prosthetic treatment plan. In numerous clinical situations, implants can clearly contribute to a notable simplification of therapy, frequently enabling removable prostheses to be avoided, keeping it less invasive with respect to remaining tooth structure. The aim of the present study was to clinically assess the peri-implant and periodontal conditions after the placement of crowns in partially edentulous patients.

MATERIALS AND METHODS

Twenty-five participants with 28 implant supported crowns were recruited in the study. After the insertion of suprastructure, meticulous scaling and root planing were performed on adjacent teeth which served as control. The clinical examination was carried out by a single examiner after placement of crowns at an interval of 1, 3, 6, 9, and 12 months and included the assessment of modified plaque index (mPlI), bleeding score, calculus score, probing pocket depth (PPD), and recession on the four aspects of each implant and adjacent teeth.

RESULTS

The mPlI, modified bleeding index (mBlI), calculus score, PPD, and recession decreased from 1 month to 12 months in both implants and in control teeth. The mean mPlI, mBlI, and calculus score were comparatively high in control teeth than implants. PPD was found to be more on implants than in control teeth. Recession was slightly higher in control teeth than implants throughout the study period, but it was not statistically significant.

CONCLUSION

An implant patient must always be enrolled in a supportive therapy program that involves recall visits at regular intervals.

Peri-Implant Crevicular Fluid Analysis, Enzymes and Biomarkers: a Systemetic Review

OBJECTIVES

To review the current understanding of the biomarkers and enzymes associated with different forms peri-implant diseases and how their level changes influence the pathogenesis of the inflammatory diseases around dental implants.

MATERIAL AND METHODS

An electronic search in two different databases was performed including MEDLINE (PubMed) and EMBASE between 1996 to 2016. Human studies analyse peri-implant crevicular fluid (PICF) biomarker and enzyme levels of implants having peri-implant mucositis and peri-implantitis published in English language, were evaluated. A systematic review was performed to assess which biomarkers and enzymes in PICF were used to identify the inflammatory conditions around dental implants.

RESULTS

Fifty-one articles were identified of which 41 were further evaluated and included in the analysis. Due to significant heterogeneity between included studies, a meta-analysis could not be performed. Instead, a systematic descriptive review was performed.

CONCLUSIONS

Biomarkers and enzymes in peri-implant crevicular fluid have shown promising results in differentiating from peri-implant disease condition to health. However, due to inconsistent results and acquiring much evidence from cross-sectional studies, additional evidence supported by randomized-controlled trials is needed to validate the links reported.

The Effect of Flapless and Full-thickness Flap Techniques on Implant Stability During the Healing Period

Purpose : When soft tissue flaps are reflected for implant placement, the blood supply from the periosteum to the bone is disrupted. The aim of this study was to compare the effects of the flapless (FL) and full-thickness flap (FT) techniques on implant stability. Methods : Nine patients received 22 implants. The implants were placed using the FL technique on the contralateral side of the jaw; the FT technique was used as the control technique. Resonance frequency analysis (RFA) was performed at the time of implant placement and at 6 and 12 weeks after implant placement. RFA values were compared between the FL and FT groups and between time intervals in the same group. Results : The median (interquartile range [IQR]) RFA values at the time of implant placement were 75.00 (15.00) for the FL technique and 75.00 (9.00) for the FT technique. At 6 weeks, the median (IQR) values were 79 (3.30) for the FL technique and 80 (12.70) for the FT technique. At 12 weeks, the median (IQR) values were 82.3 (3.30) for the FL technique and 82.6 (8.00) for the FT technique. There were no significant differences between the 2 techniques at the time of implant placement, after 6 weeks or after 12 weeks, with p values of 0.994, 0.789, and 0.959, respectively. There were significant differences between the RFA values at the time of implant placement and after 6 weeks for the FL technique (p=0.028) but not for the FT technique (p=0.091). There were also significant differences between the RFA values at 6 weeks and the RFA values at 12 weeks for the FL technique (p=0.007) and for the FT technique (p=0.003). Conclusion : Periosteum preservation during the FL procedure will speed up bone remodeling and result in early secondary implant stability as well as early loading.

Can peri-implant crevicular fluid assist in the diagnosis of peri-implantitis? A systematic review and meta-analysis

BACKGROUND

A broader understanding of the immune inflammatory profile of peri-implant diseases could be helpful in the development of host-targeted preventive and therapeutic strategies. The aim of this study is to answer two clinical questions: 1) whether patients with peri-implantitis (PP) present higher prevalence of any specific inflammatory cytokine in peri-implant crevicular fluid (PICF) compared with healthy patients; and 2) whether local inflammation measured in PICF can be used as a predictor for incipient PP.

METHODS

A systematic review of the literature on the most common cytokines released in PICF in healthy and PP-affected sites was conducted from 1996 up to and including October 2013 using predefined search strategies. Cross-sectional and prospective longitudinal studies were considered. Meta-analyses were done separately for healthy, mucositis (MU), and PP outcomes.

RESULTS

Interleukin (IL)-1β was the most studied cytokine (n = 12), followed by tumor necrosis factor (TNF)-α (n = 10). Other cytokines were also linked to PP, such as IL-4, IL-6, IL-8, IL-10, IL-12, and IL-17. Statistical differences were revealed when IL-1β release was compared between healthy implant sites and PP (P = 0.001) or MU sites (P = 0.002), respectively; when PP and MU were compared, no statistical differences could be detected (P = 0.80). For TNF-α release, significant differences were found between healthy and PP implants (P = 0.02).

CONCLUSIONS

PICF containing inflammatory mediators, such as IL-1β and TNF-α, can be used as additional criteria for a more robust diagnosis of peri-implant infection. Additionally, once the inflammatory process is installed, no differences were found between peri-implant MU and PP.

Comparison of pro-inflammatory cytokines and bone metabolism mediators around titanium and zirconia dental implant abutments following a minimum of 6 months of clinical function

OBJECTIVES

Dental implant abutments are fundamental prosthetic components within dentistry that require optimal biocompatibility. The primary aim of this cross-sectional study was to preliminarily assess differences in the pro-inflammatory cytokine and bone metabolism mediator protein expression in the peri-implant crevicular fluid (PICF) adjacent to transmucosal abutments.

MATERIAL AND METHODS

Abutments were fabricated from either titanium or zirconia in patients previously receiving single-tooth implant therapy. All subjects sampled in this study had an identical implant system and implant-abutment connection. Participants (n = 46) had an average time of clinical function for 22 months (6.2-72.8 months, ±SD 17 months) and received a clinical and radiographic examination of the implant site at the time of PICF sampling using a paper strip-based sampling technique. Cytokine, chemokine, and bone metabolism mediator quantities (picograms/30 s) were determined using a commercial 22-multiplexed fluorescent bead-based immunoassay instrument. A total of 19 pro-inflammatory cytokines and seven bone metabolism mediators were evaluated.

RESULTS

Multivariable analyses provided no evidence of a group (titanium or zirconia), gender, or age effect with regard to the expression of pro-inflammatory mediators evaluated. Significant (P = 0.022) differences were observed for the bone mediator leptin, with titanium abutments demonstrating significantly elevated levels in comparison with zirconia. Osteopontin demonstrated a significant (P = 0.0044) correlation with age of the subjects.

CONCLUSIONS

No significant differences in pro-inflammatory cytokine or bone metabolism mediator profiles were observed biochemically, with the exception of leptin, for the abutment biomaterials of titanium or zirconia The molecular PICF findings support the observed clinical biocompatibility of both titanium and zirconia abutments.

What is the effect of initial implant position on the crestal bone level in flap and flapless technique during healing period?

Purpose

The level of the implant above the marginal bone and flap design have an effect on the bone resorption during the healing period. The aim of this study is to detect the relationship between the level of the implant at the implant placement and the bone level at the healing period in the mesial and distal side of implants placed with flapless (FL) and full-thickness flap (FT) methods.

Methods

Twenty-two nonsubmerged implants were placed with the FL and FT technique. Periapical radiographs were taken of the patient at implant placement, and at 6 and 12 weeks. By using computer software, bone level measurements were taken from the shoulder of the healing cap to the first bone implant contact in the mesial and distal side of the implant surface.

Results

At 6 weeks, the correlation between the crestal bone level at the implant placement and crestal bone level of the FT mesially was significant (Pearson correlation coefficient=0.675, P<0.023). At 12 weeks, in the FT mesially, the correlation was nonsignificant (Spearman correlation coefficient=0.297, P<0.346). At 6 weeks in the FT distally, the correlation was nonsignificant (Pearson correlation coefficient=0.512, P<0.107). At 12 weeks in the FT distally, the correlation was significant (Spearman correlation coefficient=0.730, P<0.011). At 6 weeks in the FL mesially, the correlation was nonsignificant (Spearman correlation coefficient=0.083, P<0.809). At 12 weeks in the FL mesially, the correlation was nonsignificant (Spearman correlation coefficient=0.062, P<0.856). At 6 weeks in the FL distally, the correlation was nonsignificant (Spearman correlation coefficient=0.197, P<0.562). At 12 weeks in the FL distally, the correlation was significant (Pearson correlation coefficient=0.692, P<0.018).

Conclusions

A larger sample size is recommended to verify the conclusions in this preliminary study. The bone level during the healing period in the FT was more positively correlated with the implant level at implant placement than in the FL.

Comparison of peri-implant crevicular fluid levels of adrenomedullin and human beta defensins 1 and 2 from mandibular implants with different implant stability quotient levels in nonsmoker patients

BACKGROUND AND OBJECTIVE

To achieve satisfactory osseointegration, primary stability and healthy peri-implant tissue must be available. In this study, our objective was to compare the adrenomedullin, human beta-defensin (hBD)-1 and hBD-2 levels in implants with different implant stability quotient (ISQ) values and with different peri-implant tissue health values in the peri-implant crevicular fluid.

MATERIAL AND METHODS

Thirty patients with 60 endosseous osseointegrated implants were included in this study. Following the completion of the osseointegration process, these implants were divided into two main groups: a group of 15 implants with peri-implantitis (peri-implantitis: 40 ≤ ISQ ≤ 80 peri-implantitis, n = 15) and a group of 45 implants with healthy peri-implant tissue. The healthy peri-implant tissue group was further divided into three subgroups according to their ISQ values (Healthy-60: 60 ≤ ISQ ≤ 70, healthy peri-implant, n = 15; Healthy-80: 71 ≤ ISQ ≤ 80, healthy peri-implant, n = 15; and Healthy-100: 81 ≤ ISQ ≤ 100, healthy peri-implant, n = 15). The levels of adrenomedullin, hBD-1 and hBD-2 in the peri-implant crevicular fluid were assessed using ELISAs.

RESULTS

When the peri-implant clinical measurements were compared within groups, they were found to be highest in the peri-implantitis group and lowest in the Healthy-100 group. The adrenomedullin, hBD-1 and hBD-2 levels in the peri-implant crevicular fluid of the peri-implantitis group were found to be significantly higher than those in the Healthy-60, Healthy-80 and Healthy-100 groups. When only the healthy peri-implant tissue groups were evaluated, the adrenomedullin, hBD-1 and hBD-2 levels in the peri-implant crevicular fluid of the Healthy-60 group were found to be significantly higher than those in the Healthy-80 and Healthy-100 groups. The lowest adrenomedullin, hBD-1 and hBD-2 levels were observed in the Healthy-100 group.

CONCLUSION

In cases of peri-implantitis, higher adrenomedullin, hBD-1 and hBD-2 levels were observed. These results indicate the presence of a tissue response to prevent the creation of a pathological environment in the peri-implant tissue. In groups with healthy peri-implant tissues, the ISQ value decreases as the adrenomedullin, hBD-1 and hBD-2 levels increase. This condition is thought to be caused by increased dental plaque accumulation and bone resorption in addition to increased lateral implant movements and colonization of microorganisms in the microcavities between the implant elements.

Levels of Immunoglobulin A1 in Peri-Implant Fluid and Saliva from Patients with Mucositis: A Preliminary Study

There are no studies evaluating the possible use of immunoglobulin A1 (IgA1) as an early marker for peri-implant inflammation. The aim of this study was to evaluate the IgA1 levels in peri-implant sulcular fluid (PISF) and saliva of partially edentulous patients as an indicator of mucositis. Twenty-seven patients were examined to determine the peri-implant status based on probing depth and bleeding on probing. Saliva and PISF around dental implants were collected and the IgA1 levels were evaluated by Elisa assay. IgA1 in saliva and PISF of these patients were compared and their correlations with clinical parameters were evaluated. Differences in IgA1 levels in saliva (821.1 ± 290.6; 779.8 ± 401.5) and PISF (26.6 ± 20.7; 25.1 ± 20.5) of healthy and mucositis groups, respectively were not observed (p>0.05). Correlation between clinical parameters and IgA1 in saliva or PISF was not observed in healthy or mucositis groups (p=0.607; p=0.826, respectively). These results suggest that IgA1 cannot be used as an immunological marker of mucositis.

History of Chronic Periodontitis Is a High Risk Indicator for Peri-Implant Disease

The success rates in implant dentistry vary significantly among patients presenting previous history of periodontitis. The aim of this study was to evaluate if patients with history of chronic periodontitis (CP) are more susceptible to peri-implant disease (PID) than those without history of CP. Two hundred and fifteen individuals, under periodontal maintenance, presenting 754 osseointegrated implants, were selected for this study. The patients were divided into two groups according to the peri-implant status: Control group (patients without PID; n=129) and PID group (patients with PID; n=86). All peri-implant regions were clinically evaluated, including analyses of mucosa inflammation, edema and implant mobility. Periapical radiography assessed the presence of peri-implant bone loss. According to the clinical/radiographic characteristics, patients in Control and PID groups were diagnosed as having CP or not. Nominal variables were evaluated by the chi-square test. The distribution of numeric variables was analyzed by Shapiro-Wilk test. Student's t-test and Mann-Whitney test were used to analyze significant differences for parametric and non-parametric data. A p-value <0.05 was considered significant. There was a highly significant correlation between CP history and PID (p<0.0001). Patients with CP had 4 times more chance of developing PID than patients with healthy periodontal tissues. Also, CP patients showed higher bleeding on probing (p=0.002) and bone loss around implant (p=0.004) when compared with patients without CP. In conclusion, history of CP is a high risk factor for the development of PID, irrespective of gender or region of implant placement.

Would Nitric Oxide be an Effective Marker for Earlier Stages of Peri-Implant Disease? An Analysis in Human Peri-Implant Sulcular Fluid

Nitric oxide has an important effect on host immune response. However, little has been studied in relation to its potential as a possible diagnostic tool in peri-implant disease. The present study analyzed nitrite levels in the peri-implant sulcular fluid (PISF) of implants with mucositis and the correlation of these nitrite levels with clinical parameters using a simplified fluid collection methodology. Twenty-five partially edentulous patients showing peri-implant mucositis were evaluated, and the peri-implant status was determined based on current clinical parameters: probing depth (PD) and bleeding on probing (BOP). The sulcular fluid (SF) around teeth (control) and implants were collected, and the nitrite levels were evaluated using the Griess method. The mean probing depth (mm) was significantly higher (P &lt; .0001) in implants (2.852 ± 0.6484) than in control teeth (1.585 ± 0.3636). The mean total nitrite level (μM) was statistically higher (P = .0069) in implants with mucositis (14.34 ± 11.83) than in control teeth (9.316 ± 5.534). No correlation was observed between the total nitrite levels and the PD mean in the control group (P = .2558, r = −0.2361) or in the implant group (P = .1160, r = −0.3224), as well as the number of faces showing bleeding on probing (P = .8747, r = 0.0332). These results demonstrated that the nitrite levels were higher in inflamed areas. According to the methodology applied and results obtained, the higher nitrite levels in inflamed areas suggest that, in the future, nitrite could be used as a marker of peri-implant mucositis associated with clinical data to monitor the cure or evolution of the disease.

Prosthodontic considerations designed to optimize outcomes for single-tooth implants. A review of the literature

BACKGROUND

The aim of this study was to review the literature on the restoration of single-tooth implants, and to develop evidence-based conclusions to optimize aesthetic, biologic and patient-related outcomes.

METHODS

An electronic and hand search was conducted using the search terms 'dental implants, single-tooth; dental restoration, temporary; dental impression materials; dental impression technique; dental prosthesis, implant-supported; dental prosthesis design; dental abutments; dental occlusion; maintenance; survival; and survival analysis'. Resultant titles were screened, and full text was obtained where relevant. The authors selected the most appropriate articles, giving preference to systematic reviews and long-term, patient-based outcome data.

RESULTS

Thirty-nine articles were selected and critiqued by the authors.

CONCLUSIONS

There was strong suggestion by several authors that peri-implant soft tissue aesthetics can be sculpted through provisional restoration contour, but there are no clinical outcome studies to define or support this claim. Laboratory studies demonstrate that pick-up type impression copings in conjunction with elastomeric impressions are the most accurate means for transferring implant position to a dental cast. Laboratory and finite-element analysis studies suggest implants with an internal-type connection show improved stress distribution, but supportive clinical data are lacking. The authors of this review favour a screw-retained prosthesis for retrievability. Clinical and histological studies show that gold, titanium and zirconia ceramic abutment materials exhibit excellent biological responses, although there is insufficient data on the clinical service provided by zirconia as an implant-substructure material. The literature does not associate any particular occlusal scheme with superior clinical outcomes. Implant-borne single crowns offer comparable clinical service to tooth-borne fixed dental prostheses. However, single-tooth implant restorations are associated with an increased incidence of biological and technical complications.

Cytokines in pathogenesis of peri-implantitis

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Tumor necrosis factor-alpha levels after surgical anti-infective mechanical therapy for peri-implantitis: a 12-month follow-up

BACKGROUND

The aim of the present case series was to evaluate the effects of a surgical anti-infective mechanical therapy for peri-implantitis on clinical parameters and tumor necrosis factor-alpha (TNF-alpha) levels at 12 months post-therapy.

METHODS

Ten patients with peri-implantitis were treated with open surgical debridement, abrasive sodium carbonate air-powder, and resin curets. Clinical parameters were recorded before and 3 and 12 months after therapy. At these time points, the total amounts of TNF-alpha in the peri-implant crevicular fluid were measured by enzyme-linked immunosorbent assay.

RESULTS

At 3 and 12 months, the anti-infective therapy resulted in significant improvements in all clinical parameters (P <0.05). Moreover, the total amount of TNF-alpha was significantly reduced at 3 and 12 months after therapy compared to baseline (P <0.05), paralleling the changes in mean probing depth and bleeding on probing.

CONCLUSION

The anti-infective mechanical therapy reduced the crevicular levels of TNF-alpha in sites affected by peri-implantitis over a period of 12 months, and this phenomenon was associated with improvements in clinical parameters.

Changes in inflammatory mediators in peri-implant fluid after implant insertion

BACKGROUND

Endosseous dental titanium implants have revolutionized restorative dentistry and have made a significant impact on improved patient care. The aim of this study was to compare and evaluate the influence of the placement technique on periodontal health.

METHODS

A baseline examination was performed in patients with submerged and non-submerged titanium implants, including an evaluation of plaque index (PI), gingival index (GI), periodontal probing depth (PD), clinical attachment level (CAL), and bone level, as well as histamine and arachidonic acid metabolite concentrations, in the peri-implant crevicular fluid. Examinations were repeated after 12, 24, and 36 months.

RESULTS

Bone loss was significantly higher in the submerged group relative to the non-submerged group at 3 years (P <0.01), with a slight increase at 24 months. All clinical parameters were significantly higher in the submerged group relative to the non-submerged group at 24 and 36 months (P <0.05 for PI; P <0.01 for GI, PD, and CAL). The mean levels of histamine and other inflammatory mediators were significantly higher, whereas 15(S)-hydroxy-5,8,11,13-eicosatetraenoic acid concentrations were significantly reduced in the submerged group, with a high correlation with periodontal indices at 24 and 36 months (P <0.001).

CONCLUSION

This longitudinal study suggested that submerged implants present a number of risks for periodontal complications compared to non-submerged implants, which can be evidenced by inflammatory mediator variations in the peri-implant crevicular fluid.

Differential cytokine expressions affect the severity of peri-implant disease

OBJECTIVE

This study assessed gene expression by quantitative polymerase chain reaction of inflammatory- [interleukin (IL)-12, tumor necrosis factor-alpha (TNF-alpha), IL-4, and IL-10] and osteoclastogenesis-related factors [receptor activator of NF-kappaB ligand (RANKL) and osteoprotegerin (OPG)] in sites exhibiting different severities of peri-implant disease.

MATERIAL AND METHODS

Peri-implant soft tissue biopsies (n=48) were harvested from healthy implant (HI), mucositis (MC), initial peri-implantitis (IP) and severe peri-implantitis (SP) sites.

RESULTS

IL-12 and TNF-alpha mRNA levels were higher in SP, followed by IP and MC (P <0.05). IL-4 was higher in HI, followed by MC, SP and IP (P <0.05). IL-10 was the lowest in HI, while no differences were detected among the diseased groups (P>0.05). OPG mRNA levels were higher in HI, followed by IP, SP and MC, whereas RANKL was increased as the peri-implantitis severity increased (P<0.05). The highest OPG/RANKL ratio was observed in HI and the lowest in SP (P<0.01).

CONCLUSION

These findings suggest that expressions of inflammatory- and osteoclastogenesis-related factors may play an important role in the onset and severity of the peri-implant diseases.

Association of the composite IL-1 genotype with peri-implantitis: a systematic review

OBJECTIVE

Cytokine gene polymorphisms may modulate the host response to the bacterial challenge and influence susceptibility to peri-implantitis.

OBJECTIVE

To systematically review the evidence of an association between the interleukin-1 (IL-1) composite genotype, i.e. presence of the allele 2 in the gene clusters IL-1A (-889) and in IL-1B (+3953), and peri-implantitis.

MATERIAL AND METHODS

An electronic search in the National Library of Medicine-computerized bibliographic database MEDLINE and a manual search were performed. The search was conducted for longitudinal clinical trials comparing progression of peri-implantitis in IL-1 genotype positive (carrying allele 2) with IL-1 genotype negative (not carrying allele 2) subjects. Selection of publications, extraction of data and validity assessment were made independently by two reviewers.

RESULTS

The search provided 44 titles of which two longitudinal publications were included.

CONCLUSION

Based on the findings from this study, there is not enough evidence to support or refute an association between the IL-1 genotype status and peri-implantitis. Systematic genetic testing for the assessment of the risk of peri-implantitis cannot be recommended as a standard of care at this time.

Analysis of association of clinical aspects and vitamin D receptor gene polymorphism with dental implant loss

Osseointegration failure is a complex, multifactorial trait shown to concentrate in some treated populations. There has been shown evidence for genetic contribution to dental implant loss. Genetic polymorphisms have been classically considered as genetic risk factors for several diseases and, more recently, for dental implant loss.

OBJECTIVES

The purpose of this study was to access clinical factors related to failure process, and to investigate the relationship between a vitamin D receptor (VDR) polymorphism (rs731236, TaqI) and dental implant loss.

MATERIAL AND METHODS

Two hundred and seventeen unrelated patients, mean age 51.7+/-11.3 years, were divided into two groups: (i) control group (C), 137 individuals presenting at least one osseointegrated implant in function for 6 months or more and without any implant loss, and (ii) study group (S), 80 individuals presenting at least one implant loss. After DNA collection and purification, VDR TaqI polymorphism analysis was performed by polymerase chain reaction-restriction fragment length polymorphisms (PCR-RFLP). Differences between C and S, and between healthy (H; n=1232) and lost (L; n=135) implants were accessed.

RESULTS

Positive evidence of association has been detected between implant loss and the following variables: edentulism, implant position, primary stability, and implant length. Cox's regression model showed that primary stability, surgical technique and bone quantity were related to implant survival over time. No association between genotypes or alleles of VDR TaqI polymorphism and implant loss was found between the groups.

CONCLUSION

It was observed that clinical variables, but not the study polymorphism, were associated with dental implant loss.

The dimensions of keratinized mucosa around implants affect clinical and immunological parameters

OBJECTIVES

To investigate the association between keratinized mucosa (KM) width and mucosal thickness (MTh) with clinical and immunological parameters around dental implants.

METHODS

Sixty-three functioning dental implants (3I osseotite) were examined. Clinical examinations included plaque index (PI), probing depth (PD), bleeding on probing (BOP), KM width, MTh and buccal mucosal recession (MR). Peri-implant crevicular fluid (PICF) samples were collected for PgE2 assay.

RESULTS

KM width ranged from 0 to 7 mm (mean 2.5+/-2), MTh ranged from 0.38 to 2.46 mm (mean 1.11+/-0.4) and the mean MR was 0.62 mm, ranging from 0 to 3 mm. A negative correlation was found between MTh and MR (r=-0.32, P=0.01); Likewise, KM width showed a negative correlation with MR, periodontal attachment level (PAL) and PgE2 levels (r=-0.41, P<0.001; r=-0.26, P=0.04; r=-0.26, P=0.04, respectively). In contrast, a positive correlation was found between KM width and PD (r=0.27, P=0.03). When data were dichotomized by KM width, a wider mucosal band (>1 mm) was associated with less MR compared with narrow (<or=1 mm) band (0.27 and 0.9 mm, respectively, P=0.001). A wider KM band was also associated with a greater PD (3.13 mm) compared with a narrow band (2.66 mm, P=0.04). Similarly, a thick mucosa (>or=1 mm) was associated with lesser recession compared with a thin (<1 mm) mucosa (0.45 and 0.9 mm, respectively, P=0.04).

CONCLUSION

The KM around dental implants affects both the clinical and the immunological parameters at these sites. These findings are of special importance in the esthetic zone, where thin and narrow KM may lead to a greater MR.