Implant Placement Lateral to the Inferior Alveolar Nerve: Selective Indications and Treatment Outcomes-A Case Series.

Replacement of missing posterior mandibular teeth in severely atrophied jaws can be quite challenging. Various treatment options have been proposed for the rehabilitation of the deficient posterior mandible with implant-supported prostheses. Depending on the clinical situation, it may be feasible to place implants lateral to the inferior alveolar nerve, which represents a viable treatment option under the proper circumstances. This article defines the indications and limitations of this approach and presents the treatment planning and surgical management of three selected cases and their outcomes 1 to 5 years after implant loading.

Zirconium Implant as an Alternative to Titanium Implant in a Case of Type IV Titanium Allergy: Case Report.

Titanium remains the material of choice in the manufacturing of dental implants because of its exceptional biologic and mechanical properties. However, cases of allergy to titanium have been reported in the literature causing skin, mucosal reactions, systemic symptoms, and eventually implant exfoliation. Although the frequency of these cases varied between 0.6% and 5%, undiagnosed or misdiagnosed cases may possibly increase this percentage significantly. Epicutaneous, intradermal inoculation of the allergen or blood tests (LTT, MELISA, IL1ß, IL-6, TNF-α, IL-10) have been used with various degrees of sensitivity and specificity to assess Ti allergy. This case report demonstrated that titanium dental implant allergy caused rapid implant loss following an acute inflammatory reaction and its successful replacement by a one-piece zirconium implant.

Peri-implant Infection Concomitant with a Flare-up Episode of Chronic Periodontitis: An Unusual Regeneration Following Treatment and a 5-Year Follow-up.

Chronic periodontitis progression may go through phases of remission and exacerbation. The possibility of periodontal pathogens translocating from infected periodontal sites to peri-implant sites has been reported. Additionally, a history of periodontal disease seems to be a risk factor for peri-implantitis. The present case reports a flare-up of chronic periodontitis concomitant with an episode of peri-implant infection on a documented stable implant site. Periodontal infection was managed nonsurgically by scaling root planing and antibiotic treatment. Peri-implant infection was treated by open-flap debridement and implant surface decontamination. A remarkable regeneration on the peri-implant defect occurred steadily over a 3-year period, leading to a full regeneration of the site relying exclusively on the individual healing resources.

Sinus Floor Elevation Using the Lateral Approach and Window Repositioning and a Xenogeneic Bone Substitute as a Grafting Material: A Histologic, Histomorphometric, and Radiographic Analysis.

PURPOSE: Sinus floor elevation using the lateral approach and bone window repositioning and a xenogeneic bone substitute (Cerabone) has been well documented clinically. The purpose of this histologic and histomorphometric study was to determine the fate of the window, its contributing role in the healing process, and the osseoconductivity and resorption potential of the high-temperature sintered bovine bone used, as well as to correlate the histomorphometric results with sinus depth and lateral wall thickness as determined on cone beam computed tomography (CBCT). MATERIALS AND METHODS: Thirty biopsy specimens were harvested from the lateral side of the maxilla of patients operated on for sinus floor elevation and implant placement at two postoperative periods: early, group 1 (mean: 5.73 ± 0.44 months); and late, group 2 (mean: 8.68 ± 1.76 months). Sinus depth and lateral wall thickness were determined on CBCT and correlated to graft maturation. RESULTS: The repositioned bone window was microscopically detectable in both study groups and looked well integrated. Bone was found growing out of the repositioned window toward the center of the graft, most often forming a trabecular network independently from the bone matrix, which is in favor of osteogenic potential of the window. Also, newly built bone was found directly attached to the surfaces of the window, indicating bone growth via osseoconduction. Repositioned window sides showed signs of low-grade inflammation. Active osteoclasts were only found to be associated with the newly built bone matrix, hinting at an active bone remodeling process. No signs of biodegradation or remodeling of the window were detected using the tartrate-resistant acid phosphatase (TRAP) technique. The histomorphometric analysis of the tissue distribution showed similar values of newly formed bone in group 1 (22.77% ± 5.89%) and in group 2 (26.15% ± 11.18%) and connective tissue values in both study groups (42.29% ± 8.98% for group 1 vs 46.03% ± 5.84% for group 2). No significant differences were found between group 1 (34.94% ± 7.10%) and group 2 (27.82% ± 11.97%) for xenogeneic bone substitute values. Statistically significant differences were only found between connective tissue values and newly built bone values (P < .01 and P < .001, respectively). Furthermore, a significant difference was found between connective tissue values and that of bone substitute up to 12 months (P < .01). No significant correlation was found between sinus depth and lateral window thickness and histomorphometric results. CONCLUSION: The re positioned window technique appears to be a good osteoconductive barrier for bone formation. Its osteogenic potential needs to be confirmed immunochemically. High-temperature sintered bovine bone proved to be an effective slowly resorbing osseoconductive material.

Sinus Floor Elevation Using the Lateral Approach and Bone Window Repositioning I: Clinical and Radiographic Results in 102 Consecutively Treated Patients Followed from 1 to 5 Years.

PURPOSE: To determine the potential complications and clinical outcomes using the lateral sinus elevation technique with window repositioning. MATERIALS AND METHODS: One hundred nine sinus elevations were performed on 102 consecutively treated patients. Following lateral window outward fracturing, sinus mucosa was elevated, and the sinus was grafted with anorganic bovine bone. Two hundred five implants were placed: 160 concomitantly with grafting, and 45 six months after grafting. Seventeen implants replaced single missing molars. One hundred eighty-eight implants replaced multiple missing posterior teeth. The bone window was repositioned over the osteotomy site and the flap sutured. Implants were connected at 6 months and followed up from 12 to 60 months (mean: 29.8 months). In 30 cases, biopsy specimens were harvested from the lateral wall of the sinus for histomorphometric analysis. The Fisher exact test and Kruskal-Wallis test followed by the Mann-Whitney test were used for statistical analysis. RESULTS: No clinically significant complications were encountered in using this technique (mucosa tear, intraoperative bleeding, window sequestration). In three cases, the window was separated in two before outfracturing. In 20 cases, it was stabilized with a collagen fleece. Limited sinus mucosa tears occurred in 14 cases during elevation. They were patched with a collagen membrane, and 18 implants were placed in these cases. All of the latter cases osseointegrated at abutment connection with no statistically significant difference in the outcome compared with implants placed with no tear of the membrane (P < .05). The reconstruction of the lateral wall was confirmed in all cases. No significant differences in outcomes were found between the immediately and delayed placed implants (P < .05). One implant failed in the immediately placed group due to a sinus infection. All other implants were loaded and remained in function during the observation period. CONCLUSION: Lateral sinus elevation with window repositioning is safe and effective with minimal risks, such as mucosal tear, intraoperative bleeding, or window sequestration. The repositioned window can serve as an alternative for collagen membrane in containing the graft. Graft maturation, percent of vital bone formation, and the potential of the window to serve as a source of osteogenic cells need to be confirmed histomorphometrically. This will be reported in a subsequent article.

Hydrolysis of concentrated raw starch: A new very efficient α-amylase from Anoxybacillus flavothermus.

A new α-amylase from Anoxybacillus flavothermus (AFA) was found to be effective in hydrolyzing raw starch in production of glucose syrup at temperatures below the starch gelatinization temperature. AFA is very efficient, leading to 77% hydrolysis of a 31% raw starch suspension. The final hydrolysis degree is reached in 2-3h at starch concentrations lower than 15% and 8-24h at higher concentrations. AFA is also very efficient in hydrolyzing the crystalline domains in the starch granule. The major A-type crystalline structure is more rapidly degraded than amorphous domains in agreement with the observed preferential hydrolysis of amylopectin. Amylose-lipid complexes are degraded in a second step, yielding amylose fragments which then re-associate into B-type crystalline structures forming the final α-amylase resistant fraction. The mode of action of AFA and the factors limiting complete hydrolysis are discussed in details.

In depth study of a new highly efficient raw starch hydrolyzing α-amylase from Rhizomucor sp.

A new α-amylase from Rhizomucor sp. (RA) was studied in detail due to its very efficient hydrolysis of raw starch granules at low temperature (32 °C). RA contains a starch binding domain (SBD) connected to the core amylase catalytic domain by a O-glycosylated linker. The mode of degradation of native maize starch granules and, in particular, the changes in the starch structure during the hydrolysis, was monitored for hydrolysis of raw starch at concentrations varying between 0.1 and 31%. RA was compared to porcine pancreatic α-amylase (PPA), which has been widely studied either on resistant starch or as a model enzyme in solid starch hydrolysis studies. RA is particularly efficient on native maize starch and release glucose only. The hydrolysis rate reaches 75% for a 31% starch solution and is complete at 0.1% starch concentration. The final hydrolysis rate was dependent on both starch concentration and enzyme amount applied. RA is also very efficient in hydrolyzing the crystalline domains in the maize starch granule. The major A-type crystalline structure is more rapidly degraded than amorphous domains in the first stages of hydrolysis. This is in agreement with the observed preferential hydrolysis of amylopectin, the starch constituent that forms the backbone of the crystalline part of the granule. Amylose-lipid complexes present in most cereal starches are degraded in a second stage, yielding amylose fragments that then reassociate into B-type crystalline structures, forming the final resistant fraction.

In situ tracking of enzymatic breakdown of starch granules by synchrotron UV fluorescence microscopy.

Synchrotron UV fluorescence microscopy was used for the first time to visualize the adsorption and diffusion of an enzyme while degrading a solid substrate. The degradation pathway of single starch granules by two amylases, optimized for biofuel production and industrial starch hydrolysis, was followed by tryptophan fluorescence (excitation at 280 nm, emission filter at 300-400 nm) and visible light imaging. Thus, both the adsorption of enzyme onto starch granules at 283 nm resolution and the resulting morphological changes were recorded at different stages of hydrolysis. It is the first time that amylases were localized on starch without staining or adding a fluorescent probe at such high resolution. This technique presents a very high potential for imaging proteins in complex systems. Its sensitivity was demonstrated by the detection of GBSS (the granular bound starch synthase) at high recording times, GBSS being present at very low levels in maize starch granules.

Conventional and advanced implant treatment in the type II diabetic patient: surgical protocol and long-term clinical results.

PURPOSE: To investigate the effect of type-2 diabetes on implant survival and complication rate. MATERIALS AND METHODS: Prospective study enrolling type-2 diabetic patients suffering from edentulism, having a mean perioperative HbA1c level of 7.2%, and compliant with a maintenance program. All the patients underwent dental and periodontal examinations and had laboratory testing for HbA1c, fasting plasma glucose, blood lipids, and microalbuminuria. Nondiabetic patients matched for implant treatment indication served as controls. The influence of clinical diabetes-related factors and periodontal parameters (Plaque Index, bleeding on probing, probing depth) on implant survival were assessed via univariate then multivariate methods. RESULTS: Forty-five diabetic patients, followed for 1 to 12 years, mean age 64.7 years, received 255 implants: 143 following a classical protocol and 112 in cases of sinus floor elevation, immediate loading, and guided bone regeneration. Forty-five nondiabetic control patients received 244 implants: 142 following a classical protocol and 102 in cases of advanced surgery. Implant survival following conventional or advanced implant therapy was not statistically different between the well-controlled (HbA1c < 7%, P = .33) and the fairly well-controlled group (HbA1c 7% to 9%, P = .37). The overall survival rate for the diabetic group was 97.2% (control 98.8%) and was not significantly different for age, gender, diabetes duration, smoking, or type of hypoglycemic therapy. The mean peri-implant bone loss was 0.41 +/- 0.58 mm (control, 0.49 +/- 0.64 mm). PI and BOP fairly correlated with postoperative complications. HbA1c was the only multivariate independent factor affecting the complication rate (P = .04). No statistically significant difference was found for patients (P = .81) or for implants (P = .66) for the advanced surgery cases or the conventional approach in diabetic patients compared to nondiabetic patients.

Peri-implant bone loss caused by occlusal overload: repair of the peri-implant defect following correction of the traumatic occlusion. A case report.

The purpose of this case report is to demonstrate the relation between occlusal overload and peri-implant bone loss and the reversal of the situation after removal of the offending forces. The placement of an unstable removable prosthesis on 3 well-integrated implants that had been stable for 9 years caused noticeable bone loss after 6 months. The elimination of the traumatic occlusion reversed the situation, and a remarkable healing of the peri-implant tissue occurred until the pretrauma condition was nearly restored. The condition has been stable for the past 4 years.

Influence of prosthetic parameters on the survival and complication rates of short implants.

PURPOSE: Implants shorter than 10 mm can be a long-term solution for sites with limited bone height. The purpose of this study was to determine the influence of some prosthetic factors on the survival and complication rates. MATERIALS AND METHODS: Two hundred sixty-two short machined-surface Brånemark System implants were consecutively placed in 109 patients and followed for a mean of 53 months. The prosthetic parameters were recorded, and the data were examined for relation to peri-implant bone loss and biologic or biomechanical complications. RESULTS: Relatively few crown-to-implant (C/I) ratios were < 1 or > 2 (16.2%). Occlusal table (OT) width ranged from 5.4 to 8.3 mm. Opposing dentition was most often natural teeth, a fixed prosthesis supported by natural teeth, or an implant-supported fixed restoration. Occlusion with a normal buccolingual maxillomandibular relationship was found in 72.7% of the cases. No significant difference in peri-implant bone loss was correlated with C/I ratio or OT. Neither cantilever length nor bruxism had a significant effect on peri-implant bone loss. Mean bone loss was 0.74 +/- .65 mm. The difference in the complication rate (15% overall) between the bruxer and the nonbruxer group was not statistically significant (P = .51). One implant was lost in a heavy bruxer after 7 years of function. DISCUSSION: Increased C/I and OT values do not seem to be a major risk factor in cases of favorable loading. In 67% of the cases, the mesiodistal length of the prosthesis was less than the corresponding natural tooth length, which may have contributed to better load distribution and more favorable results. CONCLUSIONS: Short implants appear to be a longterm viable solution in sites with reduced bone height, even when the prosthetic parameters exceed the normal values, provided that force orientation and load distribution are favorable and parafunction is controlled.

Clinical evaluation of short, machined-surface implants followed for 12 to 92 months.

PURPOSE: Bone resorption following tooth loss often limits the quantity of bone available for implant placement. The purpose of the present study was to evaluate the clinical outcome of 10-mm or shorter machined-surface implants when used exclusively in the treatment of various forms of edentulism. MATERIALS AND METHODS: Two hundred sixty-nine screw-type Brånemark System implants (Nobel Biocare), 10 mm or shorter, were placed in 111 consecutively treated patients. Of the total, 88.8% were placed in the mandible and 11.2% were placed in the maxilla; 95.2% were used to treat partially edentulous situations, including single-tooth losses, of which 96.6% were in the premolar and molar regions. The patients were followed for periods of 12 to 92 months. RESULTS: Of the 269 placed implants, 12 were lost. The overall survival rate was 95.5%. Bone quality 2 and 3 (Lekholm-Zarb classification of 1985) was found in 88.8% of the treated sites. There was no statistical difference in the survival rate of the 10-mm implants when compared to the shorter series (P > .05) or between the various implant diameters. The mean marginal bone loss was 0.71 +/- 0.65 mm. DISCUSSION: The failure rate of 4.5% compares favorably with that of implants of different shape, surface characteristics, and length. Bone quality appeared to be the critical factor in implant survival, rather than bone quantity, in this patient series. CONCLUSIONS: This study supports the survival of short, machined-surface implants when used for the treatment of partial edentulism in bone of good quality.

Clinical and radiographic evaluation of the 5-mm diameter regular-platform Brånemark fixture: 2- to 5-year follow-up.

PURPOSE: The purpose of this study was to report the clinical results obtained with 5-mm diameter regular-platform Brånemark implants after 2 to 5 years of follow-up. A secondary aim was to compare the clinical outcome to that of adjacently placed standard 3.75-mm fixtures in the same patients under the same operative condition and in the same prosthetic construction. MATERIALS AND METHODS: Sixty patients, with a mean age of 54 years, received a total of 97.5-mm diameter regular-platform fixtures. The majority of the implants were placed at molar sites. In 41 of the patients, 53.5-mm diameter implants were placed adjacent to 62 standard 3.75-mm diameter fixtures in the same prosthetic reconstruction. All implants were submerged for an average period of 4 to 6 months. Abutment connection was done according to standard protocol. The prosthetic treatment consisted of freestanding fixed bridges. RESULTS: The cumulative survival rate of the 5-mm diameter implants loaded for a period of 2 to 5 years was 96.9%. Only three implants failed. They were placed in type 4 bone in the posterior maxilla. Bone loss over the first year was 0.70 mm and over a 3-year period 0.81 mm. Implants placed in type 4 bone showed significantly higher bone loss. No difference in the resorption rate could be found between the maxillary and the mandibular implants or between the various implant lengths. There was no significant difference between the bone loss around the 5-mm diameter fixtures and the adjacent 3.75-mm diameter standard fixtures. CONCLUSION: The present study demonstrated a high predictability of 5-mm diameter regular-platform implants when placed in the posterior maxilla and mandible.