Surgical treatment of peri‐implantitis: Prognostic indicators of short‐term results

Aim

To evaluate the clinical and radiographic short‐term (6 months) effect of surgical treatment of peri‐implantitis, and to identify prognostic indicators affecting the outcome using a multilevel statistical model.

Materials & Methods

A total of 143 implants (45 patients) with a diagnosis of progressive peri‐implantitis (progressive bone loss (PBL) ≥2.0 mm and bleeding on probing (BoP)/suppuration) received surgical treatment. Clinical and radiographic parameters were assessed 6 months postoperatively. Potential prognostic indicators on subject, implant and site level prior to surgery were analysed to evaluate the effect on individual and composite outcomes using multilevel logistic regression analysis.

Results

At the 6‐month evaluation, none of the implants demonstrated PBL and 14% of the implants were registered with the absence of bleeding and no pocket probing depth ≥6 mm. Multilevel regression analysis identified, among others, suppuration, pocket probing depth >8 mm, bone loss >7 mm and the presence of plaque as criteria associated with the outcome.

Conclusion

Resective peri‐implantitis surgery seemed to reduce the amount of peri‐implant inflammation. However, most of the sites continued to have BoP/suppuration. Thus, long‐term maintenance and evaluation is warranted. The effect of treatment was reduced by some prognostic indicators such as the presence of suppuration prior to interception and peri‐implant bone loss exceeding 7 mm.     

Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs

Objective: This study was designed to evaluate the transmucosal healing response of implants placed with the junction of the smooth surfaces, either crestal or subcrestal, into simulated extraction defects after healing periods of 1 and 3 months. Materials and methods: A total of 23 Straumann SP ?3.3 mm NN, SLA^® 10 mm implants were placed in the mandibular premolar regions of three greyhound dogs 3 months after the teeth were removed. Five control implants were placed at the crestal bone level, and test implants with surgically created peri‐implant defects of 1.25 mm wide × 5 mm depth were placed either at the crestal (nine implants) or at the 2 mm subcrestal (nine implants) bone level. Implants on the right side were placed 1 month before the dogs were sacrificed, and implants on the left side were placed 3 months before sacrifice. All dogs had daily plaque control following surgery and were sacrificed 3 months after implant placement for histological and histometric analyses. Results: Mesial–distal ground sections of the control and test implant specimens showed a greater %BIC in the coronal defect region after 3 months of healing. This healing response was incomplete for the test implants compared with the control implants after a 1‐month healing period. The histometric measurements for test implants placed at the crestal bone level or 2 mm subcrestal with surgically created peri‐implant defects were more coronal or closer to the implant margin compared with the control implants. Additionally, the degree of osseointegration between the newly formed bone and the implant surface was similar between the test implants. Conclusion: Peri‐implant defects of 1.25 mm width healed with spontaneous bone regeneration around implants placed transmucosally at crestal or 2 mm subcrestal with a high degree of osseointegration after a 3‐month healing period. To cite this article:
Tran BLT, Chen ST, Caiafa A, Davies HMS, Darby IB. Transmucosal healing around peri‐implant defects: crestal and subcrestal implant placement in dogs.
Clin. Oral Impl. Res. 21 , 2010; 794–803.
doi: 10.1111/j.1600‐0501.2010.01911.x     

One‐piece zirconia oral implants for single‐tooth replacement: Three‐year results from a long‐term prospective cohort study

Aim

This 3‐year report of a prospective long‐term cohort investigation aimed to evaluate the clinical and radiographic outcomes of a one‐piece zirconia oral implant for single‐tooth replacement.

Materials and Methods

Sixty‐five patients received a 1‐stage implant surgery with immediate temporization. Standardized radiographs were taken at implant insertion, after 1 year, and after 3 years to monitor peri‐implant bone levels. A univariate analysis of the association of different baseline parameters on marginal bone loss from implant insertion to 36 months was performed. Soft‐tissue parameters were evaluated at prosthesis insertion, after 6 months, after 1 year, and at the 3‐year follow‐up.

Results

After 3 years, six posterior site implants were lost, giving a cumulative survival rate of 90.8%. The mean marginal bone loss was 1.45 mm; 35% of the implants lost at least 2 mm bone, and 22% more than 3 mm. The univariate analysis did not identify any parameter associated with marginal bone loss. Probing depth, clinical attachment level, and bleeding index increased over 3 years, and plaque index decreased.

Conclusions

The low survival rate of the presented ceramic implant and especially the high frequency of advanced bone loss are noticeable but remain unexplained.     

Comparison of peri‐implant clinical and radiographic status around short (6 mm in length) dental implants placed in cigarette‐smokers and never‐smokers: Six‐year follow‐up results

Background

It is hypothesized that peri‐implant clinical and radiographic inflammatory parameters (probing depth [PD], bleeding on probing [BOP] and plaque index [PI]; and radiographic (crestal bone loss [CBL]) are worse among cigarette‐smokers (CS) compared with never‐smokers (NS) with short implants.

Purpose

The present 6‐year follow‐up retrospective study compared the peri‐implant clinical and radiographic parameters in CS and NS with short dental implants (6 mm in length).

Materials and methods

Fifty‐six male individuals were included. These individuals divided into 2 groups as follows: (a) Group‐1: 29 self‐reported systemically healthy CS with 48 short‐implants; and (b) Group‐2: 27 self‐reported systemically healthy NS with 43 short implants. Peri‐implant PD, PI, BOP, and CBL were measured. Group comparisons were done using the Kruskal‐Wallis test and sample size was estimated. Level of significance was set at P values < .05.

Results

In groups 1 and 2, the follow‐up durations were 6.2 ± 0.1 years and 6.1 ± 0.3 years, respectively. A cigarette smoking history of 8.9 ± 3.6 pack years was reported by individuals in Group‐1. At follow‐up, scores of peri‐implant PD, BOP, PI, and mesial and distal CBL were comparable around short implants in both groups.

Conclusion

Under strict oral hygiene maintenance protocols, short dental implants can remain functionally stable in CS in a manner similar to NS.     

Radiographic evaluation of modern oral implants with emphasis on crestal bone level and relevance to peri‐implant health

Implant stability and maintenance of stable crestal bone level are prerequisites for the successful long‐term function of oral implants, and continuous crestal bone loss constitutes a threat to the longevity of implant–supported prosthetic constructions. The prevalence/incidence and reasons for crestal bone loss are under debate. Some authors regard infection (i.e. peri‐implantitis) as the cause for virtually all bone loss, while others see crestal bone loss as an unavoidable phenomenon following surgery and implant loading. Irrespective of the cause of continuous crestal bone loss, correct usage and scientifically sound interpretation of radiographs are of utmost importance for evaluation of oral implants. The periapical radiographic technique is currently the preferred method for evaluating implant health based on bone loss, and digital radiographs allow easy standardization of the image contrast. It is suggested that baseline radiographs should be taken at the time the transmucosal part pierces the mucosal tissues and annually thereafter. The number of unreadable radiographs should be presented in scientific publications to give insights into the quality of the radiographic examination. It is suggested that not only mean values, but also the range of bone levels, should be presented to describe the proportion of implants that show continuous crestal bone loss. In the absence of other clinical symptoms, bleeding on probing around implants seems to be a weak indicator of ongoing or future loss of crestal bone. According to recent longitudinal studies on modern implant surfaces peri‐implantitis defined as ‘infection with suppuration associated with clinically significant progressing crestal bone loss’ occurs with a prevalence of less than 5 % in implants with 10 years in function.     

A prospective,multi‐center study assessing early loading with short implants in posterior regions. A 3‐year post‐loading follow‐up study

Background

Few prospective studies about early loading of short implant have been available and very little evidence exists on the outcomes longer than 3 years.

Purpose

To assess clinical and radiographic outcomes of 6 mm‐short implants placed in the posterior maxilla and mandible applying an early loading protocol.

Materials and methods

Ninety‐five short implants (6 mm‐short, Ø 4 mm) were placed in 45 subjects at 3 study sites, 2 or 3 implants per subject, using a one‐stage surgical procedure and loaded with a screw‐retained splinted fixed prosthesis 6 weeks later. Follow‐up took place at 6, 12, 24, and 36 months after loading. Marginal bone level changes, implant survival, clinical variables, and adverse events were assessed.

Results

The survival rate for all implants placed was 95.8%. From implant loading to 3 years follow‐up, mean marginal bone level changes were minimal (0.07 ± 0.49 mm) and the peri‐implant soft tissue status was healthy. No major technical or biological complications occurred except for the 4 early implant losses.

Conclusion

Three‐year data indicates that the use of splinted 6 mm‐short implants is a viable treatment in posterior regions with low marginal bone resorption. Early loading after 6 weeks should be taken cautiously in patients with known risk factors.     

Influence of a machined collar on crestal bone changes around titanium implants: a histometric study in the canine mandible

Background: It has been shown that peri‐implant crestal bone reactions are influenced by both a rough–smooth implant border in one‐piece, non‐submerged, as well as an interface (microgap [MG] between implant/abutment) in two‐piece butt‐joint, submerged and non‐submerged implants being placed at different levels in relation to the crest of the bone. According to standard surgical procedures, the rough–smooth implant border for implants with a smooth collar should be aligned with the crest of the bone exhibiting a smooth collar adjacent to peri‐implant soft tissues. No data, however, are available for implants exhibiting a sandblasted, large‐grit and acid‐etched (SLA) surface all the way to the top of a non‐submerged implant. Thus, the purpose of this study is to histometrically examine crestal bone changes around machined versus SLA‐surfaced implant collars in a side‐by‐side comparison. Methods: A total of 60 titanium implants (30 machined collars and 30 SLA collars) were randomly placed in edentulous mandibular areas of five foxhounds forming six different subgroups (implant subgroups A to F). The implants in subgroups A to C had a machined collar (control), whereas the implants in subgroups D to F were SLA‐treated all the way to the top (MG level; test). Furthermore, the MGs of the implants were placed at different levels in relation to the crest of the bone: the implants in subgroups A and E were 2 mm above the crest, in subgroups C and D 1 mm above, in subgroup B 3 mm above, and in subgroup F at the bone crest level. For all implants, abutment healing screws were connected the day of surgery. These caps were loosened and immediately retightened monthly. At 6 months, animals were sacrificed and non‐decalcified histology was analyzed by evaluating peri‐implant crestal bone levels. Results: For implants in subgroup A, the estimated mean crestal bone loss (± SD) was ?0.52 ± 0.40 mm; in subgroup B, +0.16 ± 0.40 mm (bone gain); in subgroup C, ?1.28 ± 0.21 mm; in subgroup D, ?0.43 ± 0.43 mm; in subgroup E, ?0.03 ± 0.48 mm; and in subgroup F, ?1.11 ± 0.27 mm. Mean bone loss for subgroup A was significantly greater than for subgroup E (P = 0.034) and bone loss for subgroup C was significantly greater than for subgroup D (P <0.001). Conclusions: Choosing a completely SLA‐surfaced non‐submerged implant can reduce the amount of peri‐implant crestal bone loss and reduce the distance from the MG to the first bone–implant contact around unloaded implants compared to implants with a machined collar. Furthermore, a slightly exposed SLA surface during implant placement does not seem to compromise the overall hard and soft tissue integration and, in some cases, results in coronal bone formation in this canine model.     

The evaluation of peri‐implant sulcus fluid osteocalcin,osteopontin, and osteonectin levels in peri‐implant diseases

1 Background

Peri‐implant mucositis is an inflammation of the soft tissues surrounding an implant. Peri‐implantitis refers to a process characterized by peri‐implant bone loss along with an inflammation of the soft tissues. Osteocalcin, osteopontin, and osteonectin proteins are related to bone remodeling. The aim of the present study was to investigate peri‐implant sulcus fluid (PISF) osteocalcin, osteopontin, and osteonectin levels in peri‐implant mucositis and peri‐implantitis.

2 Methods

Fifty‐two implants with peri‐implantitis, 46 implants with peri‐implant mucositis, and 47 control implants were included in the study. Clinical parameters including probing depth, modified sulcus bleeding index and modified plaque index were recorded. PISF osteocalcin, osteopontin, and osteonectin levels were analyzed by ELISA kits.

3 Results

There were no significant differences in PISF osteocalcin, osteopontin, and osteonectin total amounts between healthy controls, peri‐implant mucositis and peri‐implantitis groups (P > 0.05). Probing depths were not correlated with PISF osteocalcin, osteopontin, and osteonectin levels in the study groups (P > 0.05).

4 Conclusions

Soft tissue inflammation around dental implants does not cause a change in osteocalcin, osteopontin, and osteonectin levels in PISF. Also, peri‐implantitis does not seem to give rise to an increase in PISF levels of osteocalcin, osteopontin, and osteonectin.     

Submerged and transmucosal healing yield the same clinical outcomes with two-piece implants in the anterior maxilla and mandible: interim 1-year results of a randomized, controlled clinical trial

Objectives: To test whether or not transmucosal healing at two‐piece implants is as successful as submerged placement regarding crestal bone levels and patient satisfaction. Material and methods: Adults requiring implants in the anterior maxilla or mandible in regions 21–25, 11–15, 31–35 or 41–45 (WHO) were recruited for this randomized, controlled multi‐center clinical trial of a 5‐year duration. Randomization was performed at implantation allowing for either submerged or transmucosal healing. Final reconstructions were seated 6 months after implantation. Radiographic interproximal crestal bone levels and peri‐implant soft tissue parameters were measured at implant placement (IP) (baseline), 6 and 12 months. Patient satisfaction was assessed by a questionnaire. A two‐sided t‐test (80% power, significance level α=0.05) was performed on bone‐level changes at 6 and 12 months. Results: One hundred and twenty‐seven subjects were included in the 12‐month analysis (submerged [S]: 52.5%, transmucosal [TM]: 47.2%). From IP to 6 months, the change in the crestal bone level was ?0.32 mm (P<0.001) for the S group and ?0.29 mm (P<0.001) for the TM group. From IP to 12 months, bone‐level changes were statistically significant in both groups (S ?0.47 mm, P<0.001; TM ?0.48 mm, P<0.001). The mean differences of change in the bone levels between the two groups were not statistically significant at either time point, indicating the equivalence of both procedures. For both groups, very good results were obtained for soft tissue parameters and for patient satisfaction. Conclusions: Transmucosal healing of two‐piece implants is as successful as the submerged healing mode with respect to tissue integration and patient satisfaction within the first 12 months after IP. To cite this article:
Hämmerle CHF, Jung RE, Sanz M, Chen S, Martin WC, Jackowski J, Ivanoff CJ, Cordaro L, Ganeles J, Weingart D, Wiltfang J, Gahlert M. Submerged and transmucosal healing yield the same clinical outcomes with two‐piece implants in the anterior maxilla and mandible: interim 1‐year results of a randomized, controlled clinical trial.
Clin. Oral Impl. Res 23 , 2012; 211–219.
doi: 10.1111/j.1600‐0501.2011.02210.x     

Narrow‐ and regular‐diameter implants in the posterior region of the jaws to support single crowns: A 3‐year split‐mouth randomized clinical trial

Objectives

The objective of this 3‐year split‐mouth randomized controlled clinical study was to compare narrow‐diameter implants (NDIs) to regular‐diameter implants (RDIs) in the posterior region of the jaws (premolars and molars) in regards to (i) the marginal bone level (MBL) and (ii) implant and prosthesis survival and success rates.

Material and Methods

A total of 22 patients were included in the study. Each patient received at least one implant of each diameter (Ø3.3 and Ø4.1 mm), placed either in the maxilla or mandible to support single crowns. A total 44 implants (22 NDIs and 22 RDIs) were placed and included in the study. Twenty‐one implants were placed in the premolar, whereas 23 were placed in molar areas. Radiographic evaluations to access the MBL were performed immediately after implant placement, 1 and 3 years after implant loading. Peri‐implant clinical variables including probing pocket depth (PPD) and bleeding on probing (BoP) were obtained after crown delivery, 1 and 3 years after loading. Furthermore, the survival and success rates of the implants and prosthesis were also evaluated.

Results

Twenty patients were able to complete the study. There was no statistically significant difference regarding MBL between groups at implant placement (p = .084), 1‐year (p = .794) and 3‐year (p = .598) time intervals. The mean peri‐implant bone loss at 3‐year follow‐up was ?0.58 ± 0.39 mm (95% CI: ?0.751 to ?0.409) and ?0.53 ± 0.46 mm (95% CI: ?0.731 to ?0.329) for NDIs and RDIs, respectively. BoP was present at 15% and 10% of NDIs and RDIs, respectively, at 3‐year follow‐up. PPD >5 mm was observed in 5% and 0% of the implants of NDIs and RDIs, respectively, at 3‐year follow‐up. At the 3‐year examination, the implant success rates were in the NDIs and RDIs sites, respectively, 95% and 100%. The corresponding values for prosthesis success rates were 90% for NDIs and 95% for RDIs.

Conclusion

The present study demonstrated that NDIs placed to support single crowns in the posterior region did not differ to RDIs in regards to MBL, implant survival, and success rates.     

Combination of ultrasonic decontamination,soft tissue curettage,and submucosal air polishing with povidone‐iodine application for non‐surgical therapy of peri‐implantitis: 12‐month clinical outcomes

1 Background

The aim of this study is to evaluate clinical outcomes of a concept for non‐surgical peri‐implantitis combining stepwise mechanical debridement measures with adjuvant povidone‐iodine application with and without systemic antibiotics.

2 Methods

Forty‐five patients with chronic periodontitis and a total of 164 screw‐typed implants with peri‐implantitis were included. Peri‐implantitis was defined as radiographic bone loss of > 2 mm, probing depth (PD) ≥5 mm with bleeding on probing (BOP). Stepwise treatment of implants was performed with ultrasonic debridement, soft tissue curettage (STC), glycine powder air polishing (GPAP), and a repeated submucosal application of povidone‐iodine. Teeth with PD > 4 mm were treated simultaneously according to the same concept except STC. In cases with severe periodontitis (n = 24), amoxicillin and metronidazole (AM) were prescribed for 7 days.

3 Results

After 12 months, implants treated without AM showed significant reductions (P < 0.05) of mean PD (1.4 ± 0.7 mm), clinical attachment level (CAL) (1.3 ± 0.8 mm), and BOP (33.4% ± 17.2%). In deep pockets (PD > 6 mm) changes of mean PD (2.3 ± 1.3 mm), CAL (2.0 ± 1.6 mm), and BOP (44.0% ± 41.7%) were more pronounced. Intake of AM did not significantly influence the changes in these parameters. However, the reduction of implant sites with PD > 4 mm and BOP was significantly higher in patients with AM than in those without AM (31.8% ± 12.6% versus 20.8% ± 14.7%; P < 0.05).

4 Conclusions

The combination of ultrasonic debridement, STC, and GPAP with adjuvant povidone‐iodine led to significant clinical improvements at implants. Systemic antibiotics had limited effects on the reduction of persisting implant sites with treatment need.     

Crestal Bone Changes at Teeth and Implants in Periodontally Healthy and Periodontally Compromised Patients. A 10‐Year Comparative Case‐Series Study

Background: Limited data exist on the longitudinal crestal bone changes around teeth compared with implants in partially edentulous patients. This study sought to compare the 10‐year radiographic crestal bone changes (bone level [BL]) around teeth and implants in periodontally compromised (PCPs) and periodontally healthy (PHPs) patients. Methods: A total of 120 patients were evaluated for the radiographic crestal BL around dental implants and adjacent teeth at time of implant crown insertion and at the 10‐year follow‐up. Sixty patients had a previous history of periodontitis (PCPs), and the remaining 60 were PHPs. In each category (PCP and PHP), two different implant systems were used. The mean BL change at the implant and at the adjacent tooth at the interproximal area was calculated by subtracting the radiographic crestal BL at the time of crown cementation from the radiographic crestal BL at the 10‐year follow‐up. Results: At 10 years after therapy, the survival rate ranged from 80% to 95% for subgroups for implants, whereas it was 100% for the adjacent teeth. In all eight different patient categories evaluated, teeth demonstrated a significantly more stable radiographic BL compared with adjacent dental implants (teeth BL, 0.44 ± 0.23 mm; implant BL, 2.28 ± 0.72 mm; P <0.05). Radiographic BL changes around teeth seemed not to be influenced by the presence or absence of advanced bone loss (≥3 mm) at the adjacent implants. Conclusions: Natural teeth yielded better long‐term results with respect to survival rate and marginal BL changes compared with dental implants. Moreover, these findings also extend to teeth with an initial reduced periodontal attachment level, provided adequate periodontal treatment and maintenance are performed. As a consequence, the decision of tooth extraction attributable to periodontal reasons in favor of a dental implant should be carefully considered in partially edentulous patients.     

Radiographic evaluation of marginal bone maintenance around tissue level implant and bone level implant: a randomised controlled trial. A 1‐year follow‐up

The etiologic factors associated with crestal bone loss have not been comprehensively clarified. Several theories exist as to the reason for the observed changes in crestal bone height following implant restoration. In the 1990s, the wide‐diameter implants were commercially introduced. Initially, the implants were restored with standard‐diameter abutments because of lack of matching prosthetic components. Long‐term radiographic follow‐up of these ‘platform‐switched’ restored wide‐diameter dental implants has demonstrated a smaller‐than‐expected vertical change in the crestal bone height around these implants that is typically observed around implants restored conventionally with prosthetic components of matching diameters. The aim of this randomised controlled study was to assess radiographically marginal bone level alterations in implants restored according to the platform‐switching concept compared with traditionally restored implants. Fifty‐four subjects to participate in this randomised controlled study were selected. Two groups were assigned at random: control group (56 implants were restored with standard matching‐diameter abutments) and test group (58 implants were restored with medialised abutments). X‐ray explorations were taken for peri‐implant bone level at the minute the last cementing of the prosthesis and at 1‐year follow‐up. NHI Image was used to digitally process and manipulate the radiographic images and perform the measurements. Mean of bone loss with platform‐switching implants was ?0·01 mm, and the mean of bone loss with standard platform implant was 0·42 mm. Outcomes of this study indicated that the platform‐switching design could preserve the crestal bone levels to 1‐year follow‐up. There was a statistically significant difference in marginal bone loss.     

Comparison of peri‐implant clinical and radiographic inflammatory parameters among cigarette and waterpipe (narghile) smokers and never‐smokers

1 Background

The authors hypothesized that peri‐implant clinical and radiographic inflammatory parameters are worse in waterpipe smokers (WS) and cigarette smokers (CS) compared with never‐smokers (NS). The aim of the present retrospective study is to compare peri‐implant clinical and radiographic inflammatory parameters among WS, CS, and NS.

2 Methods

Forty‐four CS (group 1), 41 WS (group 2), and 43 NS (group 3) were included. Demographic data were collected using a questionnaire. Peri‐implant plaque index (PI), bleeding on probing (BOP), and probing depth (PD) were measured, and crestal bone loss (CBL) was assessed on standardized digital radiographs. Sample size was estimated, and statistical analyses were performed using Kruskal–Wallis and Wilcoxon rank‐sum tests. For multiple comparisons, Bonferroni post hoc test was performed. P values < 0.05 were considered statistically significant.

3 Results

Peri‐implant PI and PD were higher in groups 1 (P < 0.05) and 2 (P < 0.05) compared with group 3. Peri‐implant BOP was significantly higher in group 3 compared with individuals in groups 1 (P < 0.01) and 2 (P < 0.01). Peri‐implant total marginal bone loss was significantly higher in groups 1 (P < 0.05) and 2 (P < 0.05) compared with group 3. There were differences in PI, BOP, PD, and CBL among participants in groups 1 and 2.

4 Conclusions

Peri‐implant soft tissue inflammatory parameters and CBL are worse in CS and WS compared with NS. There is no difference in these parameters between CS and WS.     

Diagnostic accuracy of clinical parameters to monitor peri‐implant conditions: A matched case‐control study

1 Background

The aim of this case‐control study was to estimate the diagnostic accuracy of the standard clinical parameters in diagnosing healthy peri‐implant tissues, peri‐implant mucositis, and peri‐implantitis.

2 Methods

A case‐control study was designed to compare the clinical parameters used in the diagnosis of peri‐implant diseases such as: probingdepth (PD), bleeding on probing (BOP), mucosal redness (MR), suppuration (SUP), and plaque index (PI). Furthermore, the influence of patient‐ (sex, age) and implant‐related variables (implant neck configuration, time in function after loading) were evaluated to investigate the association with the clinical findings. The inferential analysis consisted of estimation by generalized estimating equations (GEE) of multilevel logistic regression models.

3 Results

In total, 1,572 sites were evaluated around 262 implants from 141 patients. Sites with implant mucositis showed significant levels of BOP (OR = 3.56), MR (OR = 7.66) and PD (OR = 1.48) compared to healthy sites. The specificity was 90.3% while the sensitivity was only 43.6%. Likewise, sites exhibiting peri‐implantitis showed significant levels of BOP (OR = 2.32), MR (OR = 7.21), PD (OR = 2.43) and SUP (OR = 6.81) compared to healthy sites. Again, the multiple logistic regressions showed high specificity (92.1%) but modest sensitivity (52.5%). PD was the only diagnostic marker displaying significance comparing peri‐implant mucositis and peri‐implantitis sites (OR = 1.76). Moreover, tissue‐level compared to bone‐level implants were less associated with SUP+ (OR = 0.20), and PI (OR = 0.36) and demonstrated statistical significance. In addition, age, sex, and function time significantly influenced the tested clinical parameters.

4 Conclusions

The diagnosis of peri‐implant diseases cannot rely solely upon individual clinical parameters but rather require a combination of criteria. The clinical parameters, particularly probing depth, might accurately discern between diagnoses among peri‐implant conditions. Nevertheless, the specificity of the clinical parameters surpasses the sensitivity in the detection of peri‐implant diseases, validating its potential use as a diagnostic tool.     

Effect of platform switching on peri-implant bone levels: a randomized clinical trial

Objective: The concept of platform switching has been introduced to implant dentistry based on observations of reduced peri‐implant bone loss. However, randomized clinical trials are still lacking. This study aimed to test the hypothesis that platform switching has a positive impact on crestal bone‐level changes. Material and methods: Two implants with diameters of 4 mm were inserted epicrestally into one side of the posterior mandibles of 25 subjects. After 3 months of submerged healing, the reentry surgery was performed. On the randomly placed test implant, an abutment 3.3 mm in diameter was mounted, resulting in a horizontal circular step of 0.35 mm (platform switching). The control implant was straight, with an abutment 4 mm in diameter. Single‐tooth crowns were cemented provisionally. All patients were monitored at short intervals over the course of 1 year. Standardized radiographs and microbiological samples from the implants' inner spaces were obtained at baseline (implant surgery), and after 3, 4, and 12 months. Results: After 1 year, the mean radiographic vertical bone loss at the test implants was 0.53±0.35 mm and at the control implants, it was 0.58±0.55 mm. The mean intraindividual difference was 0.05±0.56 mm, which is significantly <0.35 mm (P=0.0093, post hoc power 79.9%). The crestal bone‐level changes depended on time (P<0.001), but not on platform switching (P=0.4). The implants' internal spaces were contaminated by bacteria, with no significant differences in the total counts between the test and the control at any time point (P=0.98). Conclusions: The present randomized clinical trial could not confirm the hypothesis of a reduced peri‐implant bone loss at implants restored according to the concept of platform switching. To cite this article:
Enkling N, Jöhren P, Klimberg V, Bayer S, Mericske‐Stern R, Jepsen S. Effect of platform switching on peri‐implant bone levels: a randomized clinical trial.
Clin. Oral Impl. Res. 22 , 2011; 1185–1192.
doi: 10.1111/j.1600‐0501.2010.02090.x     

The influence of different soft‐tissue grafting procedures at single implant placement on esthetics: A randomized controlled trial

1 Background

Soft‐tissue grafting to thicken the soft tissue around dental implants was proposed to ameliorate the esthetic outcome. Traditionally, connective tissue is used as a grafting material, but a xenogeneic collagen matrix was introduced as an alternative to reduce patient morbidity.

2 Methods

A total of 60 patients randomly received either no graft (n = 20, NG group), a connective tissue graft (n = 20, CTG group), or a xenogeneic collagen matrix (n = 20, XCM group) when an implant was placed in a preserved alveolar ridge. Changes in mid‐buccal mucosal level (MBML) at 1 (T₁) and 12 (T₁₂) months after final implant crown placement were compared to the pre‐extraction level. Additionally, esthetics, marginal bone level, clinical peri‐implant parameters, and patient satisfaction were assessed.

3 Results

At T₁₂, mean changes in MBML were –0.48 ± 1.5 mm, –0.04 ± 1.1 mm, and –0.17 ± 1.3 mm in the NG, CTG, and XCM groups (P = 0.56), respectively. Regarding the other outcome variables, no significant intergroup differences were observed.

4 Conclusions

Soft‐tissue grafting at single implant placement in preserved alveolar ridges does not result in a better esthetic outcome or in better peri‐implant health and should not be considered as a standard procedure.     

Long‐Term Clinical,Microbiological, and Radiographic Outcomes of Brånemark™ Implants Installed in Augmented Maxillary Bone for Fixed Full‐Arch Rehabilitation

Purpose: The purpose of this study was to document the long‐term outcome of Brånemark implants installed in augmented maxillary bone and to identify parameters that are associated with peri‐implant bone level. Material and Methods: Patients of a periodontal practice who had been referred to a maxillofacial surgeon for iliac crest bone grafting in the atrophic maxilla were retrospectively recruited. Five months following grafting, they received 7–8 turned Brånemark implants. Following submerged healing of another 5 months, implants were uncovered and restorative procedures for fixed rehabilitation were initiated 2–3 months thereafter. The primary outcome variable was bone level defined as the distance from the implant‐abutment interface to the first visible bone‐to‐implant contact. Secondary outcome variables included plaque index, bleeding index, probing depth, and levels of 40 species in subgingival plaque samples as identified by means of checkerboard DNA–DNA hybridization. Results: Nine out of 16 patients (eight females, one male; mean age 59) with 71 implants agreed to come in for evaluation after on average 9 years (SD 4; range 3–13) of function. One implant was deemed mobile at the time of inspection. Clinical conditions were acceptable with 11% of the implants showing pockets ≥ 5 mm. Periodontopathogens were encountered frequently and in high numbers. Clinical parameters and bacterial levels were highly patient dependent. The mean bone level was 2.30 mm (SD 1.53; range 0.00–6.95), with 23% of the implants demonstrating advanced resorption (bone level > 3 mm). Regression analysis showed a significant association of the patient (p < .001) and plaque index (p = .007) with bone level. Conclusions: The long‐term outcome of Brånemark implants installed in iliac crest‐augmented maxillary bone is acceptable; however, advanced peri‐implant bone loss is rather common and indicative of graft resorption. This phenomenon is patient dependent and seems also associated with oral hygiene.     

Rehabilitation of irradiated patients with chemically modified and conventional SLA implants: five‐year follow‐up

The aim of this study is to evaluate the clinical and radiological parameters of standard SLA surface implants compared to chemically modified hydrophilic SLActive implants in irradiated patients after the initial 12‐month loading period up to 5 years. Twenty patients with a mean age of 61·1 years were treated with dental implants after ablative surgery and radio‐chemotherapy of oral cancer. All patients were non‐smokers. The placement of 102 implants (50 SLA, 52 SLActive) was performed bilaterally according to a split‐mouth design. Mean crestal bone changes were evaluated using standardised orthopantomographies and clinical parameters. Data were analysed using a Kaplan–Meier curve, Mann–Whitney U‐test and two‐factorial non‐parametric analysis. The average observation period was 60 months. The amount of bone loss at the implant shoulder of SLA implants was mesial and distal 0·7 mm. The SLActive implants displayed a bone loss of mesial 0·6 mm as well as distal 0·7 mm after 5 years. Two SLA implants were lost before loading. One patient lost five implants due to recurrence of a tumour. The overall cumulative 12‐month, 3‐year and 5‐year survival rate of SLA implants was 92%, 80% and 75·8% and of SLActive implants 94·2%, 78·8% and 74·4%, respectively. Eighteen implants were considered lost because the patients had died. Sandblasted acid‐etched implants with or without a chemically modified surface can be used in irradiated patients with a high predictability of success. Lower implant survival rates in patients with irradiated oral cancer may be associated with systemic effects rather than peri‐implantitis.