An open, randomised, multi-centre study, comparing straight and tapered apex implants design, in partially and totally edentulous maxillae.

The design of the commercially available implant OsseoSpeed® (control) was changed to a tapered apex with a smaller apical diameter; OsseoSpeed® TX (test). OBJECTIVE: The present study evaluated the clinical outcome of marginal bone level as primary outcome, and cumulative implant survival rate, primary stability and condition of the peri-implant mucosa as secondary outcomes, one year after loading. MATERIAL AND METHODS: 92 subjects (150 implants, ten centres), with partially or totally edentate maxillae were randomized to receive either test or control implants. One to six implants were placed in each subject using a one-stage surgical procedure. Subjects received a permanent prosthesis 10-12 weeks after implant placement and were followed for one year. RESULTS: 47 subjects in the test group received 82 implants and 45 subjects in the control group received 68 implants. Marginal bone level alterations from loading to 1-year follow-up was -0.02 × 0.41 mm (mean × SD) and -0.03 × 0.38 mm (mean × SD) for the test and the control group, respectively, indicating no difference between the groups. Non-inferiority was declared as confidence interval for the difference between control and test implants was no worse than 0.5 mm. The CSR was 98.8% in the test group and 100% in the control group, with no statistically significant difference between the groups. CONCLUSIONS: Change of the apical design of a commercially available implant showed no significant effect on marginal bone level and CSR compared to the control implant. Missing data and many investigators may have influenced on the result. Trial registration number: NCT01324778.

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.

Clinical and radiologic outcomes after submerged and transmucosal implant placement with two-piece implants in the anterior maxilla and mandible: 3-year results of a randomized controlled clinical trial.

PURPOSE: The aim of this investigation was to evaluate the 3-year outcomes regarding crestal bone level, clinical parameters, and patient satisfaction, following submerged and transmucosal implant placement for two-piece implants in the anterior maxilla and mandible. MATERIALS AND METHODS: Patients requiring dental implants for single-tooth replacement in the anterior maxilla or mandible were enrolled in a randomized, controlled, multicenter clinical trial. The implants were randomized at placement to either submerged or transmucosal healing, with final restorations placed after 6 months. Radiographic and clinical parameters were recorded after 1, 2, and 3 years; a questionnaire was also used to assess patient satisfaction. A two-sided, unpaired T-test (significance level p ≤ .05) was used to statistically evaluate the differences between the two groups. RESULTS: A total of 106 patients were included in the 3-year analysis. The mean change in crestal bone level from implant placement to 3 years was 0.68 ± 0.98 mm (p < .001) and 0.58 ± 0.77 mm (p < .001) in the submerged and transmucosal groups, respectively; the differences between the groups were not significant. Clinical parameters remained stable throughout the study, with no significant differences between the groups, and patient satisfaction was good or excellent for over 90% of subjects in both groups. CONCLUSIONS: The results demonstrate excellent clinical and radiographic conditions after 3 years for implants supporting single-tooth restorations, regardless of whether a submerged or transmucosal surgical technique was used.

One-year prospective three-center study comparing the outcome of a "soft bone implant" (prototype Mk IV) and the standard Brånemark implant.

BACKGROUND: Oral implant treatment ad modum Brånemark has been used for decades in the rehabilitation of edentate and partially dentate patients. Posterior jaw regions frequently exhibit bone of poor texture, and it is often difficult to obtain primary stability. Thus, it may prove beneficial to deviate from the original protocol and to use implants with a modified design, for example, with a slightly tapered geometry. PURPOSE: The purpose of the investigation was to compare the early behavior of a modified (prototype Mk IV, Brånemark System, Nobel Biocare AB, Gothenburg, Sweden; test) implant with that of the standard Brånemark implant (control) in regions of mainly type 4 bone. MATERIALS AND METHODS: Three Swedish centers participated, and a total of 44 patients were treated with oral implants for 39 maxillas and 5 mandibles. The study focused on the most distal right and left implant sites (88 implants), which were randomized to receive either a test or a control implant. Various parameters were recorded, such as registered insertion torque (OsseoCare), Nobel Biocare AB), wobbling during insertion, primary and secondary stability (as measured with resonance frequency), and marginal bone loss. The implants were followed up for 1 year. RESULTS: The test implant more frequently required a higher insertion torque and showed a significantly higher primary stability than the control implant. This difference in stability leveled out over time, and test and control implants exhibited similar secondary stability at abutment operation and at the 1-year visit. Wobbling during insertion was rarely recorded for either of the implant designs. The 1-year cumulative success rate was 93.1% for test implants and 88.4% for control implants. CONCLUSIONS: The modified implant design resulted in an increased primary stability, which may be important when placing implants in jaw regions of type 4 bone. However, independent of the achieved primary stability, successful implants tended to approach similar secondary stability in the two designs tested.

Histologic evaluation of bone response to oxidized and turned titanium micro-implants in human jawbone.

PURPOSE: To evaluate the human bone tissue response to 2 surfaces (oxidized or turned) on commercially available titanium implants. MATERIALS AND METHODS: Screw-type turned (control) and oxidized (test) micro-implants were manufactured in the same manner as commercially available turned and oxidized (TiUnite, Brånemark System) implants. The thickness of the oxide layer of the test implants was on average 10 microm, corresponding to the oxide thickness of the apical part of the TiUnite implant. Twenty patients received 1 test and 1 control micro-implant each during implant surgery. Before placement, the surface topography of the implants was characterized with an optical confocal laser profilometer. After a mean healing period of 6.6 months in the maxilla and 3.5 months in the mandible, the micro-implants and surrounding tissue were removed with a trephine bur. Histologic sections were produced, and the specimens were analyzed histomorphometrically. RESULTS: Surface roughness and enlargement were greater for the oxidized implants than for the turned implants. All micro-implants, except for 2 controls, were found to be clinically stable at the time of retrieval. Histomorphometric evaluation demonstrated significantly higher bone-to-implant contact for the oxidized implants, whether placed in the maxilla or in the mandible. Significantly more bone was found inside the threaded area for the oxidized implants placed in the mandible and maxilla, but there was no difference between implants with regard to position (maxilla or mandible). DISCUSSION: The stronger bone response to the oxidized implants may have contributed to the fact that 2 control implants but no test implants were lost. The reason for these findings may depend on one or multiple differences of the surfaces between test and control implants: (1) the thicker oxide layer itself, (2) increased surface roughness, (3) different surface morphology in terms of porosity, or (4) change in crystal structure. CONCLUSION: The present histologic study in human jawbone demonstrated a significantly higher bone response for anodic oxidized titanium implants than for implants with a turned surface.

Morbidity after chin bone harvesting--a retrospective long-term follow-up study.

BACKGROUND: Resorption of the alveolar bone after tooth extraction may result in insufficient bone volume for implant placement. Augmentation of the resorbed site using autogenous bone grafts harvested from the maxillofacial region, for example, the chin, is a common method; however, it also involves donor site morbidity. Chin graft morbidity involves impaired sensibility in the frontal teeth, the gingival, and skin postoperatively. MATERIALS AND METHODS: A group of 60 patients with partial edentulism in the maxilla and insufficient bone volume for implant therapy were augmented with bone grafts from the mandibular symphysis. The grafting procedure was performed between 1991 and 2001 with a follow-up period of 1 year after surgery. Postoperative sensibility of the lip, teeth, and gingiva was registered. Forty-six patients (18 women and 28 men) also participated in a long-term follow-up study. The mean age was 49 years (range 23-81 years) and the mean follow-up time was 7.5 years (range 4-14 years). The donor site was evaluated in four parts: a standardized clinical examination, radiographic examination and measurements, a mail-in questionnaire, and a survey of the medical records regarding complications and graft size. In the donor site, both hard tissue (mandibular symphysis and teeth) and soft tissue (ie, lower lip, infralabial area, and chin) were evaluated. A questionnaire was also answered by 38 of 46 patients. RESULTS: In the long-term follow-up, impaired tactility and sensitivity of the soft tissues were registered in 7.6%. Adjacent teeth (incisors, canines, first and second premolar) (n = 418), showed increased lamina dura in seven cases (1.7%) and four teeth had apical pathology (1.0%). The donor site (n = 45) showed good remineralization in 42 patients (93.3%), and 28 patients (62.2%) had a noticeable concavity radiologically. The questionnaires from 38 patients (answer frequency 82.3%) rated high satisfaction with the grafting and implant treatment. CONCLUSIONS: This study indicates that long-term follow-up of the chin graft donor site shows some postoperative morbidity. The most frequent disturbance was impaired sensibility in the soft tissues of the chin. The lower lip and teeth showed fewer disturbances. The rate of subjective symptoms was higher than the clinical findings but did, in general, not affect the patient in daily life. At radiographic examination, bone healing after chin graft harvesting did not regenerate to the preoperative level. The donor site showed good remineralization but left a radiologic concavity in the majority of cases.