Time sequence of bone healing around two implant systems in minipigs: preliminary histologic results.

The aim of this study was to evaluate the early phases of bone healing around two different implant surfaces. For this purpose, four minipigs were used. Implants with rough titanium surfaces (ITI sandblasted/acid-etched and Branemark TiUnite) were placed in the maxillae of the animals and sacrifice was scheduled in such a way that healing times of 3 days, 1 week, 2 weeks, 3 weeks, 4 weeks, 5 weeks, 6 weeks, and 7 weeks were obtained. Histologic analysis revealed that a similar pattern was observed in the phases of bone healing around both types of implants between 3 days and 7 weeks. This pattern consisted of the replacement of blood clot and bone debris with a provisional connective tissue in the first few weeks and with mineralized tissue and marrow spaces later on. Both rough surfaces allowed for "contact osteogenesis" to take place. (Int J Periodontics Restorative Dent 2009;29:549-555.).

Long-term survival and success of oral implants in the treatment of full and partial arches: a 7-year prospective study with the ITI dental implant system.

PURPOSE: This study evaluated the long-term survival and success of different implant-supported prostheses supported by ITI implants. MATERIALS AND METHODS: Two hundred fifty consecutive patients were rehabilitated using implant-supported prostheses. Seven hundred fifty-nine implants were loaded. Single-tooth prostheses (n = 106), cantilever fixed partial prostheses (n = 42), fixed partial prostheses (n = 137), fixed complete prostheses (n = 5), implant/tooth-supported prostheses (n = 13), and overdentures (n = 37) were used. The mean follow-up period was 3.85 years. Life table analyses were performed. Implant survival rates were calculated by means of standard life table principles. Statistical analysis was performed to compare the implant survival and success by implant placement site for each type of prosthesis. RESULTS: The cumulative implant survival rates were calculated for implants supporting single-tooth prostheses (95.6%), cantilever fixed partial prostheses (94.4%), fixed partial prostheses (96.1%), fixed complete prostheses (100%), implant/tooth-connected prostheses (90.6%), and overdentures (95.7%). Similar survival and success rates were documented for implants placed in maxillae and mandibles. Implant size did not influence survival. DISCUSSION: Seven-year survival rates were similar for implants supporting single-tooth prostheses, cantilever fixed partial prostheses, fixed partial prostheses, and implant/tooth-supported prostheses. Medium-long term implant survival and success were not influenced by the site (maxilla or mandible). Implant and prosthetic survival rates for overdentures supported by 2 implants were comparable to those for overdentures supported by 3 or more implants. CONCLUSION: Prostheses supported by ITI implants represent a reliable medium-term treatment. (More than 50 references.)

Therapy of peri-implantitis with resective surgery. A 3-year clinical trial on rough screw-shaped oral implants. Part II: radiographic outcome.

OBJECTIVES: This clinical study on therapy of peri-implantitis aimed to compare the marginal bone loss of implants treated with different surgical approaches: implantoplasty and peri-implant resective surgery only. MATERIAL AND METHODS: Over a period of 6 years, 10 patients (20 implants) were treated with implantoplasty (test group) and 9 had resective surgery (control group). A computerized analysis of radiographs was performed to calculate marginal bone loss (MBL) values mesial and distal to the implants. The measurement system was set by means of known implant sizes. Data on MBL were collected at the time of peri-implantitis diagnosis, 1, 2 and 3 years after surgery. RESULTS: There was no difference between the mean MBL values three years after implantoplasty in the test group: 0 and 0.01 mm of MBL mesial and distal to the implant were found (P>0.05). Conversely, the mean MBL values recorded in the control group were statistically different: 1.44 and 1.54 mm of MBL mesial and distal to the implant were found (P<0.05) 3 years after resective surgery. Moreover, the variation of peri-implant marginal bone after peri-implantitis surgical treatment was significantly lower in the test group than in the control group (P<0.05). CONCLUSIONS: The results of this radiographic research suggested that implantoplasty was an effective treatment of peri-implant infections and peri-implantitis progression.

Clinical and radiographic evaluation of small-diameter (3.3-mm) implants followed for 1-7 years: a longitudinal study.

Implants with a small diameter may be used where bone width is reduced or in single-tooth gaps with limited mesiodistal space, such as for the replacement of lateral maxillary or mandibular incisors. The purpose of the present longitudinal study was to compare the prognosis of narrow implants (3.3-mm-diameter) to standard (4.1-mm-diameter) implants. Over a 7-year period, 122 narrow implants were inserted in 68 patients to support 45 partial fixed prostheses (PFD) and 23 single-tooth prostheses (ST). Furthermore, 120 patients received 208 standard implants and were restored with 70 PFD and 50 ST, respectively. Clinical and radiographic assessment data were provided. Six (1.8%) out of 330 implants failed. Cumulative survival and success rates were calculated with life-table analyses processed by collecting clinical and radiographic data. For narrow implants, the cumulative survival rate was 98.1% in the maxilla and 96.9% in the mandible. The cumulative success rate was 96.1% in the maxilla and 92% in the mandible. Conversely, standard-diameter implants showed a cumulative survival rate of 96.8% in the maxilla and 97.9% in the mandible. The cumulative success rate was 97.6% in the maxilla and 93.8% in the mandible. Cumulative survival and success rates of small-diameter implants and standard-diameter implants were not statistically different (P > 0.05). Type 4 bone was a determining failure factor, while marginal bone loss was not influenced by the different implant diameters. The results suggest that small-diameter implants can be successfully used in the treatment of partially edentulous patients.

Therapy of peri-implantitis with resective surgery. A 3-year clinical trial on rough screw-shaped oral implants. Part I: clinical outcome.

The purpose of this randomized clinical trial was to compare the clinical outcome of two different surgical approaches for the treatment of peri-implantitis. Seventeen patients with ITI(R) implants were included consecutively over a period of 5 years. The patients were randomized with a lottery assignment. Ten patients were treated with resective surgery and modification of surface topography (test group). The remaining seven patients were treated with resective surgery only (control group). Clinical parameters (suppuration, modified plaque index - mPI, modified bleeding index - mBI, probing pocket depth - PPD, pseudopocket - DIM, mucosal recession - REC, probing attachment level - PAL) were recorded at baseline, as well as 6, 12, 24 and 36 months after treatment. The cumulative survival rate for the implants of the test group was 100% after 3 years. After 24 months, two hollow-screw implants of control group were removed because of mobility. Consequently, the cumulative survival rate was 87.5%. The recession index in the control group was significantly lower than in the test group at 24 months (Student's t-value of -2.14). On the contrary, control group showed higher PPD, PAL and mBI indexes than test group (Student's t-values of +5.5, +2.4 and +9.61, respectively). The PPD and mBI indexes for the implants of the control group were significantly higher at baseline than 24 months later (Student's t-values of +3.18 and +3.33, respectively). Recession and PAL indexes resulted in values significantly lower than baseline (Student's t-values of -4.62 and -2.77, respectively). For the implants of the test group PPD and mBI indexes were significantly higher at baseline than 36 months after (Student's t-values of +11.63 and +16.02, respectively). Recession index resulted in values significantly lower at baseline (Student's t-value of -5.05). No statistically significant differences were found between PAL index measurement at baseline and 36 months later (Student's t-value of +0.89). In conclusion, resective therapy associated with implantoplasty seems to influence positively the survival of oral implants affected by inflammatory processes.

Implant-supported fixed cantilever prostheses in partially edentulous arches. A seven-year prospective study.

The purpose of the following study was to evaluate the medium- to long-term prognosis of implant-supported cantilever fixed prostheses, and to establish to what degree this is influenced by factors such as length, type of cantilever (mesial or distal), and opposite dentition versus cantilever prostheses. This study was performed on a sample of 38 partially edentulous patients treated between January 1994 and March 2001 with 49 partial cantilever fixed prostheses supported by 100 implants. Marginal bone resorption (MBL) has been studied and used as a reference parameter to define therapeutic success. The MBL measurement was made possible by transposing X-ray images of patients selected on a PC and then using a software program. Statistical analysis was carried out for possible correlation between peri-implant bone resorption and the parameters considered in this study: length and type (mesial or distal) of cantilever and opposite dentition to cantilever prostheses. Seven years after loading cantilever prostheses, the overall cumulative implant survival rate (OCSR) was 97%, and the prostheses success rate is 98%. Mesial cantilever prostheses registered a lower success rate (97.1%) than distal cantilever prostheses (100%). Furthermore, a better prognosis was not observed when the opposite dentition of the prostheses comprised natural teeth, or fixed prostheses on natural teeth, when compared with the cases in which opposite teeth were implant-supported fixed prostheses. The authors concluded that medium-term prognosis of implant-supported cantilever fixed prostheses and traditional implant-supported fixed prostheses was comparable. However, a thorough pre-treatment analysis of risk factors regarding implant-supported prosthesis survival is important.

Implant-retained mandibular overdentures with ITI implants.

This prospective study has been designed to compare the results of immediate and delayed loading of implant-retained mandibular overdentures after a 2-year follow-up. Twenty patients have been randomly divided into two groups. Group 1 patients (test group) received four ITI implants in the intraforaminal area of the mandible. Octa abutments were immediately screwed on implants; 2 days after surgery, the implants were rigidly connected with a U-shaped Dolder gold bar and loaded with an overdenture. Group 2 patients (control group) received, in the same area, the same type and number of implants, which were left to heal according to the standard protocol. At 3-4 months, Octa abutments were screwed on the implants and the same prosthetic procedure of the test group was applied. The minimum follow-up period lasted 2 years, with recall appointments at 2 weeks, 1, 3, 6 months, 1 year and every following year postoperatively, evaluating: MPI, MBI, PD, Periotest and radiographic peri-implant bone resorption. Success criteria according to Albrektsson et al. were used. Only one implant out of the 40 of group 2 failed, whereas none failed in group 1. No statistical difference of the clinical parameters evaluated was noticed in the two groups. Therefore, immediate loading of implants, if connected with a U-shaped bar, can provide the same results of the 'traditional' technique as far as osseointegration and short-term survival rates of implants are concerned. Moreover, this method significantly shortens the treatment period, thus increasing patient satisfaction.