A Retrospective Study of Bone-Level Stability Around 335 Hybrid Implants Placed with an Immediate or Delayed Protocol.

This retrospective study evaluated 335 hybrid implants placed in edentulous ridges; 167 were placed with an immediate implant protocol (IIP) and 168 were placed with a delayed implant protocol. Radiographic bone level changes were measured 1 to 23 years after loading. The average bone loss between implant placement and second-stage loading was 0.16 mm in the delayed group and 0.12 mm in the IIP group. Average bone loss from implant loading to the final radiograph was 0.26 mm in the IIP group and 0.13 mm in the delayed group. There was statistically significantly more bone loss in the IIP group, in patients taking amoxicillin (vs those taking azithromycin), in sites with splinted implants (vs nonsplinted implants), and in smokers (vs nonsmokers). However, even when statistically significant, bone loss would be considered clinically insignificant by most clinicians over the 1- to 23-year follow-up.

A Retrospective Study of Bone Level Stability Around 441 Mandibular and 350 Maxillary Molar Implants Placed with an Immediate Implant Protocol.

The purpose of this retrospective study was to evaluate bone level stability around 441 mandibular and 350 maxillary molar implants, placed using an immediate implant protocol, that had been in function from 2 to 17 years postrestoration (mean: 9.9 years). Independent radiographic measurements using the known distance between threads on the specific implant that was used indicated a mean bone loss of 0.27 ± 0.68 mm around maxillary implants and 0.27 ± 0.67 mm around mandibular implants. Maxillary implants showed a statistically significant (SS) difference in bone loss on the mesial (0.20 mm) compared to the distal side (0.34 mm). In the mandibular group, there was an SS difference in bone loss around implants with wide (≥ 5 mm) and regular (< 5 mm) diameters. There was also an SS difference in bone loss in patients 50 years and older (0.28 mm) compared to patients younger than 50 (0.18 mm). In both groups, there were no SS differences in bone loss between machined- and rough-surface implants, men and women, single and splinted implants, nonsmokers and light/heavy smokers, or in patients with a penicillin allergy who were prescribed azithromycin as an alternate prophylactic antibiotic. All SS differences found in variables evaluated in the study were < 1.0 mm and therefore were considered clinically insignificant.

Long-Term Bone Stability around 312 Rough-Surfaced Immediately Placed Implants with 2-12-Year Follow-Up.

PURPOSE: The purpose of this study was to retrospectively evaluate bone stability around implants with anodic oxidized surfaces and correlate this with variables compared in a previous study. MATERIALS AND METHODS: A total of 312 implants with anodic oxidized surfaces were separated from a pool of 1,187 implants placed immediately following tooth extraction. Radiographs made at the time of implant placement were compared to radiographs taken at 2-12 years' follow-up. An independent radiologist used the known distance (mm) between peaks of adjacent threads to calculate actual bone loss measurements. Measurements were evaluated by thread of bone fill on both the mesial and distal of each implant. If <50% of the thread had bone fill, the entire thread was assumed devoid of bone. All 312 implants were measured and a Mann-Whitney rank-sum test performed to test the significance of differences in mean bone loss relative to the factors studied. RESULTS: The overall mean bone loss of the 312 implants was 0.4 mm (± 0. 80 mm) over a 2-12-year follow-up period with a mean duration of 7.4 years. Bone measurements in 95.5% of the implants were performed 6 years or more post-placement. Bone loss of <1.5 mm was found in 92% of implants. No statistically significant differences were seen in mean bone loss by gender, smokers versus non-smokers, tooth position (except for molars), or immediately loaded or immediate tooth replacement versus two-stage implants. Parameters that demonstrated statistically significant differences were splinted versus non-splinted implants, molars in maxilla versus mandible, regular (3.75-4.0 mm diameter) versus wide (5.0-6.0 mm diameter) platforms, and anodic oxidized surfaces versus other implant surfaces studied. CONCLUSIONS: The mesial-distal bone loss of anodic oxidized surface (TiUnite) implants over a 2-12-year period (mean 7.4 years) was significantly less compared with machined implants placed with the same immediate implant placement protocol (0.4 mm vs 0.6 mm). Although several variables showed statistically significant differences in bone loss, the clinical significance could be questioned, as the maximum mean bone loss was 0.3 mm or less when comparing the various factors. The procedures used to place the implant and the strict maintenance protocol appear to be important aspects of the overall long-term success reported in this study in terms of measuring marginal bone loss around immediately placed implants.

Long-term bone stability assessment around 1,187 immediately placed implants with 1- to 22-year follow-up.

PURPOSE: To evaluate the retention of bone around implants placed immediately following tooth extraction and used to support dental prostheses. MATERIALS AND METHODS: Patients from a previous study of implants placed immediately following tooth extraction were recalled to the original practice to obtain dental radiographs, which were then used to compare bone levels after 1 to 22 years of clinical function supporting dental prostheses. All radiographs were evaluated by measuring the bone within the implant threads. Implant bone maintenance was correlated with smoking history, type of implant surface, antibiotics used in conjunction with surgery, bisphosphonate use, presence of splinted restorations, anatomical location (mandible or maxilla and anterior or posterior), sex, and past periodontal disease status. Statistical analysis was performed using the Mann-Whitney test for statistical significance of differences in mean bone loss. RESULTS: A total of 1,187 implants were identified, with mean bone loss of 0.52 ± 0.79 mm. Overall bone loss was less than 1.5 mm in 90% of the implants studied. Bone loss was greater in women (0.61 ± 0.91 mm vs 0.44 ± 0.69 mm in men; P = .002). There was a correlation between bone loss and patient age at the time of tooth loss, with patients below the age of 50 experiencing significantly more loss (mean loss, 0.76 ± 1.07 mm at age < 50 and 0.46 ± 0.71 mm at age > 50; P = .008). Other significant differences were seen with implant surface (machined surface, 0.57 ± 0.77 mm; roughened surface, 0.44 ± 0.84 mm; P = .0049), maxilla vs mandible in molar areas (maxilla, 0.68 ± 0.83 mm; mandible, 0.43 ± 0.80 mm; P = .0001), and platform width (regular, 0.46 ± 0.77; wide, 0.83 ± 0.94 mm; P ≤ .0001). None of the other factors demonstrated significant differences. CONCLUSIONS: Bone loss of 1.5 mm or less was observed in 90% of the patients followed. Bone loss was correlated with age, sex, implant surface, anatomical location, and platform width. There was no statistical correlation between bone loss and any other factors evaluated.

Prospective study of 94 platform-switched implants observed from 1992 to 2006.

The purpose of the present prospective study was to evaluate implant survival and crestal bone levels around implants that used the platform-switching concept and were followed for a minimum of 11 years. Radiographs of 94 implants obtained 11 to 14 years after loading were evaluated by measuring the location of the crestal bone level relative to the implant platform. All implants had been placed at the crestal level at the time of surgery. Using the known distance of 0.8 mm between the peaks of adjacent threads, a determination was made on the radiographs of the amount of bone lost. Seventy-one of the 94 implants (75.5%) showed no bone loss on the mesial aspect, and 67 (71.3%) showed no bone loss on the distal aspect. Eighty-four percent of the mesial surfaces and 88% of the distal surfaces had 0.8 mm or less of bone loss. This is the longest follow-up to a prospective investigation of platform-switched implants and confirms the concept for preservation of crestal bone levels.

Immediate provisionalization of NanoTite implants in support of single-tooth and unilateral restorations: one-year interim report of a prospective, multicenter study.

BACKGROUND: Clinical studies reporting immediate loading of endosseous implants for edentulous cases and for fixed partial restorations have been well documented with satisfactory survival rates. Implants with a recently developed, nanometer-scale surface topography (NanoTite, BIOMET 3i, Palm Beach Gardens, FL, USA), created by discrete crystalline depositions (DCD) of calcium phosphate nano-crystals onto a dual acid-etched (DAE) surface, show enhanced early fixation in preclinical studies when compared with DAE-surfaced implants. These outcomes suggest DCD-surfaced implants may be advantageous for immediate loading approaches. OBJECTIVE: The aim of this prospective, multicenter, observational study is to report clinical outcomes for DCD-surfaced implants placed in immediate functional support of single- and multi-unit restorations according to an immediate loading protocol. MATERIALS AND METHODS: One hundred eighty-five patients enrolled at 15 international study centers received a total of 335 implants supporting 216 immediate provisionalizations consisting of 128 single-tooth restorations and 88 fixed restorations. Of the 335 implants, 77% are located in posterior and 23% in anterior regions with 55.5% of the total in mandibles and 44.5% in maxillae. Patients were evaluated for implant mobility, gingival health, symptomatology, and radiographic outcomes. RESULTS: At the time of this 1-year interim report, a total of 17 failures have been observed in 11 patients, yielding a cumulative survival rate of 94.9%. CONCLUSION: Relative to other prospective, multicenter studies of immediately loaded implants with various surface enhancements, NanoTite implants perform comparatively well when immediately provisionalized with single-tooth and fixed restorations.

A retrospective study of 1925 consecutively placed immediate implants from 1988 to 2004.

PURPOSE: The purpose of the present study was to evaluate implant survival rates with immediate implant placement (IIP) into fresh extraction sockets and to determine risk factors for implant failure. MATERIALS AND METHODS: A retrospective chart review was conducted of all patients in whom IIP was performed between January 1988 and December 31, 2004. Treatment required atraumatic tooth extraction, IIP, and mineralized freeze-dried bone allograft with an absorbable barrier to cover exposed implant threads. Implant failure was documented along with time of failure, age, gender, medical history, medications taken, postsurgical antibiotic usage, site of implant placement, and reason for implant failure. Statistical analysis was performed using chi-square and logistic regression analysis methods. RESULTS: A total of 1925 IIPs (1398 machined-surface and 527 rough-surface implants) occurred in 891 patients. Seventy-one implants failed to achieve integration; a total of 77 implants were lost in 68 patients. The overall implant survival rate was 96.0% with a failure rate of 3.7% prerestoration and 0.3% postrestoration. Machined-surface implants were twice as likely to fail as rough-surface implants (4.6% versus 2.3%). Men were 1.65 times more likely to experience implant failure. Implants placed in sites where teeth were removed for periodontal reasons were 2.3 times more likely to fail than implants placed in other sites. Patients unable to utilize postsurgical amoxicillin were 3.34 times as likely to experience implant failure as patients who received amoxicillin. CONCLUSIONS: With a 1- to 16-year survival rate of 96%, lIP following tooth extraction may be considered to be a predictable procedure. Factors such as the ability to use postsurgical amoxicillin and reason for tooth extraction should be considered when treatment planning for IIP.

A study of the fate of the buccal wall of extraction sockets of teeth with prominent roots.

The objective of this investigation was to determine the fate of thin buccal bone encasing the prominent roots of maxillary anterior teeth following extraction. Resorption of the buccal plate compromises the morphology of the localized edentulous ridge and makes it challenging to place an implant in the optimal position for prosthetic restoration. In addition, the use of Bio-Oss as a bone filler to maintain the form of the edentulous ridge was evaluated. Nine patients were selected for the extraction of 36 maxillary anterior teeth. Nineteen extraction sockets received Bio-Oss, and seventeen sockets received no osteogenic material. All sites were completely covered with soft tissue at the conclusion of surgery. Computerized tomographic scans were made immediately following extraction and then at 30 to 90 days after healing so as to assess the fate of the buccal plates and resultant form of the edentulous sites. The results were assessed by an independent radiologist, with a crest width of 6 mm regarded as sufficient to place an implant. Those sockets treated with Bio-Oss demonstrated a loss of less than 20% of the buccal plate in 15 of 19 test sites (79%). In contrast, 12 of 17 control sockets (71%) demonstrated a loss of more than 20% of the buccal plate. In conclusion, the Bio-Oss test sites outperformed the control sites by a significant margin. No investigator was able to predict which site would be successful without the grafting material even though all were experienced clinicians. This leads to the conclusion that a patient has a significant benefit from receiving grafting materials at the time of extraction.

Considerations in treatment planning of the periodontal patient.

Through the use of periodontal, orthodontic, and restorative procedures, this patient was restored to function with a stable dentition and minimal pocket depths. The patient was followed for 10 years. All areas exhibited a healthy periodontium with stability of all areas of the dentition.