Brånemark System and ITI Dental Implant System for treatment of mandibular edentulism. A comparative randomized study: 3-year follow-up

Abstract: In a randomized prospective study, two implant systems were compared in forty consecutive patients treated for mandibular edentulism. The patients were randomly allotted for treatment by the Brånemark^® two‐stage (submerged) system (BRS), or the ITI^® one‐stage (non‐submerged) system. In all, 102 Brånemark selftapping implants and 106 ITI hollow screw implants were installed and all patients were treated with full bridges. Biological and prosthodontic parameters, complications, success rates, clinical efficacy, patient satisfaction and resource requirements were evaluated. No differences were found in plaque accumulation, bleeding or complications during the follow‐up period. The BRS group showed deeper periimplant sulcus, less attached mucosa, larger bridge‐mucosa distance and higher Periotest values. Prosthetic complications were not related to the configuration of the implant systems. After 3 years, the cumulative success rates were 97.9% and 96.8% for the Brånemark and ITI systems, respectively (difference not statistically significant). One implant in the BRS group had failed to osseointegrate at the time of abutment connection, and another was lost after 2 years due to progressive breakdown of bone. In the ITI group, three implants showed progressive bone loss after 1–3 years associated with periimplant infection. All 40 bridges were intact and remained stable throughout the study. There was general patient satisfaction, but about half the Brånemark patients reported difficulty in coping with the surgical procedures. Treatment time was similar for the two systems. It is concluded that both systems meet the current requirements for dental implant systems in the treatment of mandibular edentulism.     

Hard and soft tissue changes after crestal and subcrestal immediate implant placement

Background: The purpose of this study is to assess the influence of the placement level of implants with a laser‐microtextured collar design on the outcomes of crestal bone and soft tissue levels. In addition, we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement. Methods: Twenty‐four patients, each with a hopeless tooth (anterior or premolar region), were recruited to receive dental implants. Patients were randomly assigned to have the implant placed at the palatal crest or 1 mm subcrestally. Clinical parameters including the keratinized gingival (KG) width, KG thickness, horizontal defect depth (HDD), facial and interproximal marginal bone levels (MBLs), facial threads exposed, tissue–implant horizontal distance, gingival index (GI), and plaque index (PI) were assessed at baseline and 4 months after surgery. In addition, soft tissue profile measurements including the papilla index, papilla height (PH), and gingival level (GL) were assessed after crown placement at 6 and 12 months post‐surgery. Results: The overall 4‐month implant success rate was 95.8% (one implant failed). A total of 20 of 24 patients completed the study. At baseline, there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL (P = 0.035). At 4 months, the subcrestal group had significantly more tissue thickness gain (keratinized tissue) than the crestal group compared to baseline. Other clinical parameters (papilla index, PH, GL, PI, and GI) showed no significant differences between groups at any time. A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss. A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes. Conclusions: The use of immediate implants was a predictable surgical approach (96% survival rate), and the level of placement did not influence horizontal and vertical bone and soft tissue changes. This study suggests that a thick facial plate, small gaps, and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement.     

Associations between clinical parameters assessed around implants and teeth

The aim of the present study was to clinically assess the peri-implant and periodontal conditions 1 year after placement of oral implants (ITI® Dental Implant System) in partially edentulous patients. In all, 127 patients (median age 50 years, range 17 to 79) were examined. They were all treated according to a concept of comprehensive dental care and had received fixed partial dentures (FPD). Significant differences were observed between implants and contralateral control teeth with respect to mean pocket probing depth (PPD)(2.55 mm at implants/2.02 mm at teeth), mean probing attachment level (PAL)(2.97 mm/253 mm) and bleeding on probing (BOP)(24%/12%)(Wilcoxon matched pairs sign rank test, P≥0.0l), whereas mean modified plaque index (0.22/0.30), mean modified bleeding index (0.351 0.44) and mean recession (?0.42 mm/?0.51mm) did not significantly differ between implants and teeth. Compared to control teeth, the width of keratinized mucosa at implants was significantly smaller at lingual, but not at buccal aspects. Regression analyses showed no significant association between the amount of keratinized mucosa and degree of inflammation. Recession, PPD and PAL were slightly influenced by the amount of keratinized mucosa indicating greater resistance to probing. Grouping the implants according to various lengths, type of fixation of the FPD or combination with natural teeth did not result in statistically significant different clinical parameters, whereas grouping according to different localization within the oral cavity did. For example, the mean PAL in 83 anterior implants was 2.52mm, whereas 175 posterior implants had a mean PAL of 3.18mm (Mann-Whitney U-test, P≤0.01). Regression analyses between the mean PAL for all implants in each patient and the mean PAL of the corresponding dentition revealed an r² of 0.23 (P≤0.01). Using multiple regression analysis, the mean PAL of the implants showed to be significantly influenced by the combined factors “fullmouth” PII, “fullmouth” BOP and mean PAL of all teeth. The resuhs of this study suggest that in partially edentulous patients the overall periodontal condition may influence the clinical condition around implants and thus reinforces the importance of periodontal treatment prior to and supportive periodontal therapy after the incorporation of osseointegrated oral implants.     

Basic surgical principles with ITI implants

The basic surgical principles governing the placement of ITI implants are based on research-oriented developments in harmony with evidence-based and outcome-oriented clinical procedures. In the past 15 years, the range of implant indications has been significantly widened, and partially edentulous patients clearly represent the majority of patients seeking treatment with dental implants today. An important aspect of the successful rehabilitation of patients with ITI implants is the careful selection of implant candidates with respect to systemic and local risk factors. These factors are presented based on current knowledge. Today, solid-screw implants in various screw dimensions and neck configurations comprise the ITI Dental Implant System. These different implant types are necessary to handle the full range of implant indications, in particular in partially edentulous patients. The main clinical factors are presented for the selection of the appropriate implant type, length and diameter. These implants are utilized both in a non-submerged and in a submerged approach. The main goal of surgical therapy is low trauma and the least demanding surgical procedure for patient and clinician to optimize the cost-effectiveness of implant therapy. Hence, a non-submerged approach is preferred in all sites without esthetic priority, such as in fully edentulous patients or in posterior sites of partially edentulous patients. These indications clearly represent the majority of implant patients. In esthetic sites, a submerged approach is utilized to satisfy the specific esthetic demands. The possibility to successfully utilize short implants (6 and 8 mm) and a reduced healing period of 3 months are further advantages of ITI implants due to favorable properties of the rough TPS surface. With the introduction of the microrough SLA surface, a reduction of the healing period to 6 weeks facilitates further progress towards simplification of implant therapy. In summary, the ITI Dental Implant System represents a scientifically well-documented, complete implant system for the treatment of fully and partially edentulous patients, offering straightforward surgical concepts based on predictable treatment outcome and excellent cost-effectiveness.     

The Significance of Keratinized Mucosa on Implant Health: A Systematic Review

Background: Whether a minimal width of keratinized mucosa (KM) is required to maintain peri‐implant tissue health has been a topic of interest. This systematic review and meta‐analysis aims to investigate the effect of KM on various peri‐implant health‐related parameters. Methods: An electronic search of five databases (from 1965 to October 2012) and a hand search of peer‐reviewed journals for relevant articles were performed. Human cross‐sectional or longitudinal studies with data on the relationship between the amount of KM around dental implants and various peri‐implant parameters, with a follow‐up period of at least 6 months, were included. Results: Eleven studies, seven cross‐sectional and four longitudinal, were included. Weighted mean difference (WMD) and confidence interval (CI) were calculated with meta‐analyses for each clinical parameter. The results showed statistically significant differences in plaque index (PI) and modified PI (WMD = ?0.27, 95% CI = ?0.43 to ?0.11), modified gingival index (mGI) (WMD = ?0.48, 95% CI = ?0.70 to ?0.27), mucosal recession (MR) (WMD = ?0.60 mm, 95% CI = ?0.85 to ?0.36 mm), and attachment loss (AL) (WMD = ?0.35 mm, 95% CI = ?0.65 mm to ?0.06 mm), all favoring implants with wide KM. However, comparisons of other parameters (bleeding on probing, modified bleeding index, GI, probing depth, and radiographic bone loss) did not reach statistically significant differences. The result of heterogeneity test showed only one parameter (AL, P value for the χ² test = 0.30 and I² test = 18%) had a low degree of heterogeneity among analyzed studies; meta‐analyses of other parameters presented moderate‐to‐high degree of heterogeneity. Limitations of the present review include limited number of selected studies (n = 11), existence of heterogeneity and publication bias, and only English‐written articles searched. Conclusion: Based on current available evidence, a lack of adequate KM around endosseous dental implants is associated with more plaque accumulation, tissue inflammation, MR, and AL.     

Clinical and radiographic comparison of implants in regenerated or native bone: 5-year results

Purpose: The aim of this study was to test whether or not implants associated with bone regeneration show the same survival and success rates as implants placed in native bone in patients requiring both forms of therapy. Material and methods: Thirty‐four patients (median age of 60.3 years, range 18–77.7 years) had been treated 5 years before the follow‐up examination. Machined screw‐type implants were inserted following one of two surgical procedures: (1) simultaneously with a guided bone regeneration (GBR) procedure, which involved grafting with xenogenic bone substitute material, autogenous bone or a mixture of the two and defect covering with a bio‐absorbable collagen membrane (test) and (2) standard implantation procedure without bone regeneration (control). For data recording, one test and one control implant from each patient were assessed. Examination included measurements of plaque control record (PCR), probing pocket depth (PPD), bleeding on probing (BOP), width of keratinized mucosa (KM), frequency of situations with supra‐mucosal location of the crown margin, implant survival assessment and radiographic examination. Radiographs were digitized to assess the marginal bone level (MBL). Differences between groups were tested using the one‐sample t‐test. The estimation of survival rate was based on Kaplan–Meier analysis. Results: The follow‐up period of the 34 GBR and 34 control implants ranged from 49 to 70 months (median time 57 months). Cumulative survival rates reached 100% for the GBR group and 94.1% for the control group without statistical significance. No statistically significant differences for clinical and radiographic parameters were found between the two groups regarding PCR, BOP, PPD, KM and MBL. Conclusion: The present study showed that, clinically, implants placed with concomitant bone regeneration did not performed differently from implants placed into native bone with respect to implant survival, marginal bone height and peri‐implant soft tissue parameters.     

Clinical outcome of submerged vs. non-submerged implants placed in fresh extraction sockets

Aim: The aim of this study was to compare the clinical outcome of submerged vs. non-submerged tapered implants placed into fresh extraction sockets.
Materials and methods: A prospective, controlled, multicenter, randomized, clinical trial has been performed in two centers in Rome and Torino (Italy). Thirty healthy patients were recruited according to the following inclusion criteria: need for an immediate post extraction implant, ages between 18 and 70, horizontal defect depth <2 mm, smokers <10 cigarettes/day and absence of any circumstance or condition that could represent contraindications to implant surgery. The patients were randomly allocated to submerged or non-submerged treatment groups immediately after flap elevation and tooth extraction. Submerged implants were exposed 8 weeks after the first surgery; all implants were loaded with provisional restorations 12 weeks after the first surgery and with definitive restoration 12 weeks thereafter. Clinical and radiographic parameters were evaluated at baseline, at implant loading and at the 1-year follow-up visit.
Results: The results showed statistically significant differences between the two groups in the mean value of keratinized tissue (KT) height after surgery that was significantly reduced for submerged implants when compared with transmucosal implants (mean reduction of KT at year follow-up: T group 0.2 mm, S group 1.3 mm; P =0.007).
Conclusion: Similar outcomes were found for submerged and non-submerged implants placed in fresh extraction sockets with a horizontal peri-implant defect smaller than 2 mm, except for a reduction of KT in the submerged group. Either with a submerged or a non-submerged procedure, 1 mm of mean soft tissue recession is seen after 1 year when compared with the pre-extraction situation.     

Periodontal parameters of osseointegrated dental implaits. A 4‐year controlled follow‐up study

The aim of this study was to evaluate the periodontal parameters of osseointegrated dental implants. The condition of the peri‐implant mucosa was assessed using periodontal parameters, i.e., of plaque index, bleeding on probing, probing pocket depth, probing attachment level and Periotest® scores as well as a radiographic parameter, over a 4‐year follow‐up period. 32 non‐submerged ITI dental implants, all placed in the mandible, were studied in 12 patients who had good oral hygiene. All patients were regularly recalled at 6‐month intervals. The overall implant success rate was 100%. None of the implants showed any signs of inflammation, radiographic bone loss or any detectable mobility during the follow‐up period. Methods similar to those used to evaluate the natural dentition were effectively employed to assess the clinical status of the dental implants. The diagnostic value of these parameters could not, however, be determined from this study due to the absence of any peri‐implant tissue complications. The results indicated that some periodontal parameters of healthy peri‐imolant mucosa might be slightly different from healthy periodontal tissue.     

A prospective multicenter study using two different surgical approaches in the mandible with turned Brånemark implants: conventional loading using fixed prostheses

Background: The use of a submerged implant system in a nonsubmerged surgical procedure has been reported to have promising results. At the time this study was initiated, no prospective, comparative studies with randomization between submerged and nonsubmerged surgical techniques had been published. Purpose: To evaluate the submerged and nonsubmerged surgical techniques when treating mandibular edentulism using a submerged implant system, with regard to implant survival and complications. Materials and Methods: A total of 77 patients were included and treated at nine clinics in Sweden and Norway. In total, 404 Brånemark System implants (standard and MkII implants) were inserted in the edentulous mandible; 198 implants according to the nonsubmerged protocol and 206 implants according to the traditional submerged procedure. The follow‐up period was up to 36 months after prosthesis insertion. Results: In the nonsubmerged group, 17 implants out of 198 implants (8.6%) were lost and in the submerged group, 5 out of 206 implants (2.4%) were lost. All implant failures occurred before the delivery of the final prosthesis. No major complications were reported during the implant surgery. However, at the clinical check‐up postoperatively and at the abutment connection surgery, 6 patients in the nonsubmerged group complained of pain at the implant sites, whereas there were no complaints of pain in the submerged group. Conclusions: The results of this study suggest that a turned Brånemark implant designed for a submerged implant placement procedure can be used in a nonsubmerged procedure and may be as predictable as the conventional submerged approach.     

Tissue integration of non‐submerged implants. l‐year results of a prospective study with 100 ITI hollow‐cylinder and hollow‐screw implants.

It has been postulated that the wound healing in a closed submerged location is one of the prerequisites for osseointegration of dental implants. The purpose of the present study was to evaluate the tissue integration of intentionally non-submerged titanium implants inserted by a one-stage surgical procedure. 100 ITI implants were consecutively placed in 70 partially edentulous patients. After a healing period free of masticatory loading for at least 3 months, the implants were examined. The clinical status showed for all implants neither detectable mobility nor signs of a peri-implant infection. Therefore, prosthetic abutments were inserted, and the patients were restored with fixed partial dentures. All patients were regularly recalled at 3-month intervals, and no patient dropped out of the study. Thus, all 100 implants were re-evaluated 12 months following implantation. Plaque- and sulcus bleeding indices, probing depth, clinical attachment level, width of keratinized mucosa, and periotest scores were assessed. In addition, standardized radiographs were analyzed for the presence of peri-implant radiolucencies and for the location of alveolar bone levels around the implants. Based on predefined criteria, the implants were classified as successful or failing. 98 implants were considered successful, and 1 implant failing. The remaining implant exhibited a peri-implant infection requiring local and systemic antimicrobial treatment. The results of this short-term study indicate that intentionally non-submerged ITI implants yield a high predictability for successful tissue integration.     

Bone level alterations at implants placed in the posterior segments of the dentition: outcome of submerged/non-submerged healing. A 5-year multicenter, randomized, controlled clinical trial

Objective: To determine if longitudinal bone level change at Astra Tech^? implants placed in the posterior part of the dentition was influenced by the healing conditions provided following implant placement, i.e., submerged or non‐submerged healing. Material and methods: Eighty‐four patients and 115 fixed partial dentures (FPDs or cases) entered the study. The cases were randomized into two implant installation groups: initially non‐submerged (group A) or initially submerged (group B) implants. Three hundred and twenty‐four implants were installed (group A=153; group B=171): 145 in the maxilla and 179 in the mandible. Radiographs from the implant sites were obtained at FPD insertion (baseline) and subsequently every 12 months. In the radiographs, the position of the marginal bone at the mesial and distal aspects of the implants was determined and the radiographic (Rx) bone level change over time was calculated. Results: Seven implants failed to integrate (four in group A and three in group B). During the 5 years of monitoring, three implants had to be removed and 35 implants were lost to follow‐up. The Rx bone level alteration that occurred during year 1 was 0.02±0.38 mm in group A and 0.17±0.51 mm in group B. During the subsequent 4 years there was some further Rx bone loss in group B (0.02±0.62 mm), while in group A there was some gain of bone (0.07±0.5 mm). Conclusion: The peri‐implant bone level change and number of biological complications that took place during the 5 years was small and unrelated to the surgical protocol used for implant placement.     

Early loading (2 or 6 weeks) of sandblasted and acid-etched (SLA) ITI implants in the posterior mandible. A 1-year randomized controlled clinical trial

The aim of this 1-year prospective controlled clinical trial was to evaluate the effect of early loading of ITI solid screw titanium implants with a sandblasted and acid-etched (SLA) surface on clinical and radiographic parameters. MATERIAL AND METHODS: Twenty-seven consecutively admitted patients presenting bilateral edentulous posterior mandibular areas and in need of prosthetic reconstruction were recruited. Sixty-seven ITI standard solid screw implants with an SLA surface, a diameter of 4.1 mm and a length of 8, 10 or 12 mm were installed bilaterally in molar and premolar areas according to a one-stage surgical protocol. One week (test) and 5 weeks (control) after implant placement, solid ITI prosthetic abutments were connected using a torque of 35 N cm. No provisional restoration was fabricated. Two weeks (test) and 6 weeks (control) after implant placement, porcelain-fused-to-metal single-tooth crowns were cemented. Clinical measurements were obtained at day 0 and 2, 6, 12, 24 and 52 weeks thereafter. Periapical radiographs were taken immediately after implant placement, after 6 weeks and at the 1-year examination. RESULTS: After 1 year, implant survival was 100%. Two test and one control implants rotated at the time of abutment connection and were left unloaded for 12 additional weeks. At the 1-year examination, no statistically significant differences were found between the test and control sites with respect to pocket probing depths (2.6 mm +/- 0.5 vs. 2.7 mm +/- 0.5), mean clinical attachment levels (3.1 mm +/- 0.4 vs. 3.2 mm +/- 0.5), mean percentages of sites bleeding on probing (9.7% vs. 8.3%), mean widths of keratinized mucosa (1.8 mm +/- 0.4 vs. 1.9 mm +/- 0.5), mean PerioTest values (-1.4 PTV +/- 0.9 vs. -1.6 PTV +/- 0.8) or mean crestal bone loss measurements (0.57 mm +/- 0.49 vs. 0.72 mm +/- 0.50). CONCLUSION: Based on these results, loading of titanium implants with an SLA surface as early as 2 weeks did not appear to jeopardize the osseointegration healing process in the posterior mandible. Furthermore, implants rotating at 35 N cm, if left unloaded for additional 12 weeks, did not negatively affect clinical and radiographic outcomes.     

Significance of keratinized mucosa in maintenance of dental implants with different surfaces

BACKGROUND: The need for keratinized mucosa (KM) or immobile keratinized mucosa (i.e., attached mucosa [AM]) for the maintenance of osseointegrated endosseous dental implants has been controversial. The purpose of this study was to investigate the significance of KM in the maintenance of root-form dental implants with different surfaces. METHODS: A total of 339 endosseous dental implants in place for at least 3 years in 69 patients were evaluated. The width of KM and AM, modified plaque index (mPI), gingival index (GI), modified bleeding index (mBI), probing depth (PD), and average annual bone loss (ABL) were measured clinically and radiographically by a masked examiner. Based on the amounts of KM or AM, implants were categorized as follows: 1) KM <2 mm (KL); 2) KM > or =2 mm (KU); 3) AM <1 mm (AL); and 4) AM > or =1 mm (AU). Implants were further subdivided into the following four subgroups based on their surface configurations: 1) smooth surface implants (SI) with KM <2 mm (SKL); 2) SI with KM > or =2 mm (SKM); 3) rough surface implants (RI) with KM <2 mm (RKL); or 4) RI with KM > or =2 mm (RKM); or 1) SI with AM <1 mm (SAL); 2) SI with AM > or =1 mm (SAM); 3) RI with AM <1 mm (RAL); or 4) RI with AM > or =1 mm (RAM). The effect of KM or AM on clinical parameters was evaluated by comparing the different KM/AM groups. In addition, the significance of the presence of KM on implant prostheses types (i.e., fixed versus removable) and on implant locations (i.e., anterior versus posterior) was evaluated. RESULTS: Comparison of ABL among the four subgroups in KM or AM failed to reveal statistically significant differences (P >0.05); however, statistically significantly higher GI and mPI were present in SKL or SAL compared to the other three subgroups (P <0.05). GI and mPI were significantly higher in KL (0.94 and 1.51) than KU (0.76 and 1.26) and higher in AL (0.95 and 1.50) than AU (0.70 and 1.19) (P <0.05), respectively. The difference in GI between posterior implants with or without an adequate amount of KM was also significant (P <0.05). CONCLUSIONS: The absence of adequate KM or AM in endosseous dental implants, especially in posterior implants, was associated with higher plaque accumulation and gingival inflammation but not with more ABL, regardless of their surface configurations. Randomized controlled clinical trials are needed to confirm the results obtained in this retrospective clinical study.     

Five-year results of fixed implant-supported rehabilitations with distal cantilevers for the edentulous mandible

Objectives: The purpose of this study was to evaluate the survival rate, success rate and primary complications associated with mandibular fixed implant‐supported rehabilitations with distal cantilevers over 5 years of function. Material and methods: In this prospective multi‐center trial, 45 fully edentulous patients were treated with implant‐supported mandibular hybrid prostheses with distal extension cantilevers. Data were collected at numerous time points, including but not limited to: implant placement, abutment placement, final prosthesis delivery, 3 months and 5 years post‐loading. Biological, implant and prosthetic parameters defining survival and success were evaluated for each implant including: sulcus bleeding ndex (SBI) at four sites per implant, width of facial and lingual keratinized gingiva (mm), peri‐implant mucosal level (mid‐facial from the top of the implant collar, measured in mm), modified plaque index (MPI) at four sites per implant, mobility and peri‐implant radiolucency. Survival was defined as implants or prostheses that did not need to be replaced. Success rate was defined as meeting well‐established criteria that were chosen to indicate healthy peri‐implant mucosa osseointegration, prostheses success and complications. Results: A total of 237 implants in 45 completely edentulous patients were included in the study. In each patient, four to six implants were placed to support hybrid prostheses with distal cantilevers. Cantilevers ranged in length from 6 to 21 mm, with an average length of 15.6 mm. The ages of the patients ranged from 34 to 78 with a mean age of 59.5 years. The survival rate of implants was 100% (237/237) and for prostheses 95.5% (43/45). The overall treatment success rate was calculated as 86.7% (39/45). Of the six patients that have not met the criteria for success, two patients required replacement of the entire prosthesis and four patients presented >four complications events. Conclusion: Fixed implant‐supported rehabilitation with distal cantilever resulted in a reliable treatment modality over the 5‐year observation period. Although biological parameters of MPI, SBI, keratinized tissue and peri‐implant mucosal levels showed statistically significant differences over time, the mean values for each patient remained within the normal limits of oral health. Complications were categorized as biological or technical. The majority of complications were technical complications (54/79) and of these most involved fracture of the acrylic teeth and base (20/54). While the survival rate was 100% for implants and 95.5% for prostheses, the application of strict criteria for treatment success resulted in an overall treatment success rate of 86.7%.     

Prospective study of the impact of peri‐implant soft tissue properties on patient‐reported and clinically assessed outcomes

1 Background

It has been proposed that the presence of a zone of keratinized mucosa (KM) around implants is associated with less discomfort during brushing and improved esthetic outcomes. Therefore, mucogingival procedures have been recommended for patients with discomfort during brushing, and to enhance esthetic results around implants without KM. However, no study has systematically assessed and compared discomfort during brushing, patient soft tissue esthetic satisfaction, and other clinical parameters between implants with and without KM.

2 Methods

Group 1 included patients with implants surrounded by KM, whereas patients in Group 2 had no KM around implants. Patient discomfort during brushing and esthetic satisfaction were measured with a visual analog scale and compared between the 2 groups using a mixed model. Clinical width of KM, probing depth, peri‐implant recession, plaque index, and bleeding on probing were compared within and between groups 3 and 6 months following implant restoration.

3 Results

Twenty‐four patients (12 in each group) were evaluated at the 3‐ and 6‐month follow‐up visits. Patients without peri‐implant KM were less satisfied with the esthetics of the soft tissue around their implants (P < 0.01). However, lack of KM was not associated with discomfort during brushing. In Group 1, width of KM was significantly increased after 6 months (P < 0.01). There was greater recession around implants without KM after 3 months (P < 0.01), but not after 6 months.

4 Conclusions

Patients reported that presence or absence of keratinized mucosa did not affect discomfort associated with brushing. Yet, esthetically, patients preferred implants with a zone of keratinized mucosa.     

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.     

Single-tooth replacement by immediate implant and connective tissue graft: a 1-9-year clinical evaluation

OBJECTIVES: The aim of the present study was to evaluate the long-lasting efficacy of a combined surgical protocol, using immediate implant and subepithelial connective tissue graft for single-tooth replacement. The advantages of this single-center, longitudinal, randomized, blind examiner research were the following: preservation of both keratinized mucosa amount and bone tissue, optimal peri-implant marginal sealing, satisfactory aesthetic results, reduction in treatment time. MATERIALS AND METHODS: In the time period from 1990 to 1998, 116 patients were consecutively admitted for treatment with a total of 116 solid screw ITI-implants supporting single crowns. Ninety-six patients underwent the proposed combined treatment (test group), while 20 received only single immediate implants (control group). The observation time extended from 1 up to 9 years. RESULTS: The 9-year cumulative survival rate was 100% for both test and control groups. Comparative statistical analysis of soft and hard tissue peri-implant parameters demonstrated better results in the test group than in the control during every single 3-year analysis and especially in the last observation interval. The test group also showed very good results in terms of aesthetic parameters, which estimated the keratinized mucosa width, the alignment of crown emergence profile and the patient's satisfaction. CONCLUSION: Single-tooth replacement by immediate solid screw ITI implants in association with connective tissue autograft was demonstrated to be a predictable procedure. Moreover, this treatment can be considered as a sure system to reach an excellent functional and harmonious aesthetic restoration.     

愈合期埋植型和非埋植型种植体周围牙槽骨吸收情况观察

目的：观察比较愈合期两段式埋植型和非埋植型种植体周围牙槽骨吸收情况是否存在差异。方法：收集种植义齿修复下颌后牙区牙体缺损患者44例共94颗,其中54颗两段式埋植型Frialit-2种植体和40颗两段式非埋植型ITI种植体,根据种植体植入术后和愈合后数字化全景X线片来进行种植体周围牙槽骨高度的测量。结果：显示愈合期两段式埋植型Frialit-2种植体和非埋植型ITI种植体周围骨吸收值不存在统计学差异（p=0．667〉0．05）。结论：在本实验条件下,愈合期埋植型和非埋植型种植体周围牙槽骨骨吸收改变与种植体的植入方式无关。     

A long-term follow-up study of non-submerged ITI implants in the treatment of totally edentulous jaws. Part I: Ten-year life table analysis of a prospective multicenter study with 1286 implants

In this prospective multicenter study, non-submerged ITI implants were followed in order to evaluate their long-term prognosis in fully edentulous jaws. A total of 1286 implants were inserted in 233 consecutive patients and, after a healing period of three to six months, the successfully integrated implants were restored with 163 overdentures and 95 fixed full-arch bridges. This prospective study not only calculated the 10-year cumulative survival and success rates for the 1286 implants by life table analysis, but also evaluated the actual survival and success rates for 498 implants after at least five years of functional loading. In addition, cumulative success rates were calculated for implant subgroups according to implant length and location. Additional analyses were performed to evaluate the estimated and actual survival and success rates of the implants in relation to various prosthetic rehabilitation techniques. The 10-year cumulative survival and success rates were 95.9% and 92.7%, respectively. The actual 5-year survival and success rates of the first 498 implants that were inserted were 97.7% and 95.0%, respectively. The analysis of implant subgroups showed slightly more favourable cumulative success rates for 12 mm long implants (93%), in comparison to 10 mm and 8 mm long implants (91.6% and 89.6%, respectively). The cumulative success rate for mandibular implants (approximately 94%) was also more favourable than that for maxillary implants (approximately 91%). Patients who were loaded with both maxillary and mandibular prostheses maintained success rates well above 90%; while only implants that were inserted to support maxillary overdentures that were retained by Dolder bars showed a success rate below 90%.     

Radiological and clinical follow-up of machined- and anodized-surface implants after mean functional loading for 33 months

Abstract: The purpose of this retrospective study was to compare peri‐implant bone loss and mucosal conditions around machined‐surface (MS) and anodized‐surface (AS) interforaminal implants in the mandible at least 30 months after placement. Fifty patients, each treated with four interforaminal screw‐type implants consecutively, were included. Thirty‐one patients (62%) with a total number of 124 implants (64 MS and 60 AS implants, both Brånemark type MKIII) were available for follow‐up. Rotational panoramic radiographs were used for evaluating marginal bone loss. Clinically, marginal plaque index (mPI), bleeding on probing (BOP) and pocket probing depth (PPD) were evaluated. AS implants showed significantly less marginal bone loss than MS implants (−1.17±0.13 vs. −1.42±0.13 mm; P=0.03). Marginal bone loss around distal implants was less pronounced at AS implants (−1.05±0.14 mm) when compared with MS implants (−1.46±0.14 mm; P=0.05). Within the smoking group, there was less peri‐implant bone loss around AS implants than around MS implants (−1.08±0.27 vs. −1.83±0.2; P=0.04). No differences between MS and AS implants were found with respect to mPI (57% vs. 67%), BOP (21% vs. 17%) and mean PPD (2.59±0.29 vs. 2.56±0.28 mm). Overall, both types of implants, in combination with bar‐supported overdentures, can produce excellent long‐term results in the interforaminal edentulous mandible with less peri‐implant bone loss around rough implant surfaces, which had beneficial effects at distal implants and in smokers.