Imperforate titanium shell enclosing recombinant human bone morphogenetic protein-2-induced bone formation for high-profile dental implants in rabbit tibia.

PURPOSE: To evaluate the use of a nonperforated titanium occlusive device over high-profile dental implants in rabbit tibia using recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) for augmentation grafting. MATERIALS AND METHODS: Eight New Zealand white rabbits were used for the experiment. All rabbits underwent computed tomography of the right tibia. A custom titanium shell was manufactured for each rabbit using a computer-assisted design to confine the graft. Three high-profile implants were placed in the right tibia of each rabbit; the middle implant was placed 8 mm in supracrestal fashion and the adjacent implants were placed 5 mm in supracrestal fashion. There were 4 groups (n = 2 per group): non-shell control, titanium shell only, titanium shell over buffered collagen, and titanium shell over the ACS enriched with rhBMP-2. The animals were sacrificed after 6 or 12 weeks. Histologic preparation was carried out to evaluate bone formation. RESULTS: After 6 weeks, negligible bone growth was found around the implants. After 12 weeks, there was minimal bone formation around the implants in the control group, whereas in the group treated with ACS enriched with rhBMP-2, the titanium shell was filled with mature bone, which was expressed at the implant surface, the shell's interior, and the exterior surfaces. CONCLUSION: The placement of ACS enriched with rhBMP-2 beneath an occlusive nonperforated titanium shell confining high-profile dental implants resulted in visibly more formation of mature bone.

The use of free fat tissue transfer from the buccal fat pad to obtain and maintain primary closure and to improve soft tissue thickness at bone-augmented sites: technique presentation and report of case series.

PURPOSE: Atrophic ridges usually have both hard and soft tissue shortages, and bone augmentation can make soft tissue closure difficult. The aim of this case series is to present a new method utilizing transfer of free fat tissue grafts (FFG) from the buccal fat bad (BFP) during bone augmentation to enhance immediate primary soft tissue closure and improve long-term soft tissue thickness and quality at the recipient site. MATERIALS AND METHODS: Patients with moderate to severe ridge atrophy in different regions of the jaws were treated over a 4-year period with bone augmentation and FFG. The BFP was the donor site for the FFG. Patients were examined clinically and radiographically (periapical) every 2 weeks. At 4 months, computed tomography was performed to evaluate the bone gain. Reentry was performed after 4 to 5 months to evaluate the soft tissue, obtain specimens for histologic examination, and insert implants. RESULTS: Twenty patients (18 women, 2 men; mean age 43 years) were followed for 4 to 42 months and received 92 implants in the augmented sites. The healing process was uneventful, with minimal morbidity. Bone volume increased by 4 to 8 mm horizontally and 3 to 6 mm vertically. Thick soft tissue was obtained at the recipient sites and around the dental implants, and histologic specimens showed that the FFG was replaced by fibrous tissue. CONCLUSIONS: Harvesting of the FFG from the BFP is a simple procedure with minor complications, and manipulation and handling of the graft are easy. The FFG enhances primary soft tissue closure of augmented bone, prevents dehiscences, improves long-term soft tissue thickness, and mimics the attached gingiva in its fibrous healing.

Biomechanics and peri-implantitis: The effect of a subcrestal wing-thread to decrease alveolar crestal bone strain. theory, finite element analysis, and clinical application.

PURPOSE: This study used finite element analysis and a clinical case example to test the hypothesis that a wing-thread placed 4 mm below the top of an implant would decrease crestal bone loss in function. MATERIALS AND METHODS: Finite element analysis was used to compare standard and wing-thread implants subjected to axial and off-axis forces based on the hypothesis that decreasing bone strain at the alveolar crestal margin improves peri-implant bone stability. A clinical case example of the wing-thread implant was followed for 30 months. RESULTS: Stress concentration was diminished at the crest when a wing-thread was used compared to a standard implant body. Ninety-degree lateral forces were diminished by a factor of 10 in the wing-thread implant. A patient followed for 30 months showed stable bone levels around the wing-thread implants. CONCLUSION: The wing-thread hypothesis appears to have some support for increasing bone stability based on finite element analysis and early clinical results.

New-design dental implants: a 1-year prospective clinical study of 344 consecutively placed implants comparing immediate loading versus delayed loading and flapless versus full-thickness flap.

PURPOSE: This study compared the 1-year success rates of immediately loaded dental implants to delayed loaded implants, regardless of the surgical technique (flapless or conventional full-thickness flap) and regardless of extraction time. It also examined whether the surgical technique had an influence on the success rate of the immediately loaded implants. MATERIALS AND METHODS: A total of 344 dental implants, some with a new expanded winged-thread design, were placed in 155 patients; 53% of the implants were immediately loaded. Of the immediately loaded implants, 68.9% were placed with a flapless surgical technique and 88% were placed in extraction sites. Pocket depth, mobility, bleeding on probing, presence of erythema, pain, or radiolucency around the implants, as well as clinical findings, were recorded. Implants were followed from placement through definitive restoration. Descriptive, univariate, and multivariate analyses using clustered marginal approach of the Cox proportional hazards model were applied. RESULTS: Of the 344 implants in the study, 10 (2.9%) failures were recorded, 7 of which were immediately loaded; however, there was no significant difference in failure rates between the immediate and delayed loading groups. Seven of the implants that failed were placed with a flapless (extraction site) technique; however, there was no significant difference in the failure rates between the flapless versus full-thickness flap technique in immediately loaded implants. CONCLUSIONS: The clinical success of immediately loaded implants after 1 year showed no difference from the success rate of delayed loaded implants. The implantation procedure (flapless versus conventional flap) or extraction time also had no influence on the success rate of the immediately loaded implants.

Recombinant human bone morphogenetic protein-2 confined by an imperforate titanium shell over high-profile dental implants in rabbit tibiae: a pilot bone augmentation study.

PURPOSE: To evaluate the use of a nonperforated titanium occlusive device over a bone morphogenetic protein-2 in an absorbable collagen sponge (BMP-2/ACS) in grafting the bone around high-profile (ie, supracrestal) dental implants in rabbit tibiae. MATERIALS AND METHODS: Eight New Zealand white rabbits were used for the experiment. Two implants were placed in the right tibia of each rabbit, with 4 mm of each implant placed supracrestally ("high-profile" placement) in four groups of two rabbits each: control, titanium shell only, titanium shell over buffered collagen, and titanium shell over BMP-2/ACS. The animals were sacrificed after 3 or 6 weeks. Calcified and nondecalcified histologic preparation was carried out to evaluate bone formation and degree of osseointegration. RESULTS: Three of the eight animals developed tibial fractures. The two BMP-2 test animal tibiae remained intact, with the 3-week specimen showing very little bone formation inside or outside of the titanium chamber and the 6-week specimen showing bone mostly outside of the chamber. CONCLUSION: The placement of BMP-2 beneath an occlusive nonperforated titanium shell next to a high-profile implant did not result in significant bone formation. .

Salivary biomarker analysis complementing regular clinical examination.

AIM: Tools for the diagnosis and evaluation of the severity and prognosis of periodontitis are currently insufficient. The aim of the current study was to find an array of salivary biomarkers that would be both sensitive and specific enough to be used as a complement to regular clinical examination. Furthermore, we investigated salivary markers of successful periodontal treatment to elucidate the underlying mechanism of disease. PATIENTS & METHODS: Saliva was collected from periodontitis patients during illness and following successful disease termination. Parameters measured included sodium, potassium, chloride, calcium, phosphate, magnesium, total protein, Alb, LDH, amylase, IL-1α, uric acid and carbonyls. RESULTS: Seven of the parameters analyzed were significantly altered when the disease is active and may be considered biomarkers. CONCLUSION: Salivary composition reflects disease severity and response to therapy, suggesting the efficacy of saliva monitoring for periodontal disease status and care.

Innovations in dental implant design for current therapy.

The use of osseointegrated dental implants has gained momentum, mainly in the last 20 years. Research and development in the field of implantology are constantly focusing on implant redesign to continue to try and improve implant success. The current aim of implant design is to address situations prone to failure, such as cases of low bone quality or cases of concomitant systemic diseases that compromise healing.

Innovations in dental implant design for current therapy.

The use of osseointegrated dental implants has gained momentum, mainly in the last 20 years. Research and development in the field of implantology are constantly focusing on implant redesign to continue to try and improve implant success. The current aim of implant design is to address situations prone to failure, such as cases of low bone quality or cases of concomitant systemic diseases that compromise healing.

Horizontal alveolar ridge distraction in an edentulous patient.

PURPOSE: Full fixed dental rehabilitation, including attachment based over denture (to dental implants) is the optimal solution for edentulous patients, although the insertion of implants will be impossible when the alveolar ridge has been horizontally and severely absorbed. A full arch narrow ("knife-edge") alveolar crest creates a "borderline" condition. Dental implants cannot be inserted into a narrow ridge, which is also at risk of rapid absorption, especially under the pressure of a full denture. Current clinical solutions have been limited. In bone augmentation, the bone absorption rate has been approximately 50%, requiring 6-month therapy prolongation for the grafted bone to consolidate. MATERIALS AND METHODS: We have described an edentulous patient whose "knife-edge" maxillary alveolar crest was widened with crest expanders (horizontal distractors). RESULTS: Only 6 weeks after initiation of the distraction, a wide enough ridge had been created, allowing bilateral insertion of implants, followed by attachment-based full dental rehabilitation. Bone augmentation was avoided, and the implants were placed in the correct lateral position, with sufficient attached gingiva obtained. CONCLUSIONS: Horizontal crest expanding in narrow-alveolar edentulous patients can significantly reduce both morbidity and the therapeutic period and substantially increase the therapeutic success rate, based on both soft tissue and bone distraction. With this technique, our patient was without the denture for only 6 weeks.

A novel technique for vertical bone augmentation in the premaxillary region.

A severely absorbed alveolar ridge in an edentulous premaxillary region is often augmented vertically with various methods to allow for dental implant insertion. Such a severely absorbed ridge most often results from loss of bone due to periodontitis or trauma or after dental extraction; and if socket preservation is not performed immediately after extraction, the alveolus narrows and its vertical dimension may often be reduced by 4 to 5 mm. We introduce a new technique for bone augmentation in the premaxillary region, in which vertical bone augmentation can be performed simultaneously with the insertion of dental implants. The dental implants fix the bone transferred to the maxilla, and particulate bovine bone is placed in the gap between the 2 segments. This method involves a single operation only, requires minimal chair time, and reduces postoperative pain and swelling and involved gingival trauma. In addition, the period required before prosthodontic rehabilitation is shortened.

The salivary tip of the p53 mutagenesis iceberg: novel insights.

Salivary malignancies are rare, heterogeneous, unpredictable in their clinical behavior and seldom studied. This study focused on examining the expression of mutated p53, the most prevalent mutated gene related to human cancer, in a rather large cohort of salivary malignancies (n = 70) and for a prolonged period (20 years). P53 was found to be a most powerful predictor for poor survival and more so when the tumor concurrently expressed TUNEL and heparanase markers, dramatically dropping the survival probability of the patients to 0! Survival probability at 6 years for patients with tumors stained negatively vs. positively for p53, TUNEL and heparanase was 100% vs. 49% while at 18 years this probability dropped to 67% vs. 0%, respectively (p = 0.023). Significant correlation rates were found between age and poor survival, age and p53, and p53 and other co-existing malignancies. These findings support mutated p53 as a prognostic predictor and a pivotal player in salivary carcinogenesis. Significantly more extensive therapy applied to salivary p53-positive patients did not improve mortality rate, questioning the justification for such extensive therapy and emphasizing the need to understand p53, TUNEL and heparanase biological pathways and develop additional therapeutic tools for fighting salivary cancer.

TUNEL as a tumor marker of tongue cancer.

Squamous cell carcinoma (SCC) of the tongue has an increasing incidence, a high morbidity rate and a 50% 5-year mortality rate. We analyzed the rate of apoptosis using TDT-mediated dUTP-biotin nick end-labeling (TUNEL), p53 and heparanase in 73 patients with tongue cancer by immonohistochemistry, and tested data for correlation with survival, tumor size, grade and metastasis. TUNEL staining was strong in 54% of the tumors; the remainder lacked staining, as did all healthy control tissues. Significant correlations were found between TUNEL staining level and p53 expression rates (p=0.016) and between TUNEL and heparanase (p=0.039). Moreover, while the cumulative 5-year survival probability for tumors not stained for TUNEL and p53 was 63%, but dropped to 34% with TUNEL staining; for lack of TUNEL and heparanase (=0), 5-year survival rate was 50%, while staining presence (>0) reduced survival to 34%. TUNEL joins other biomarkers in indicating prognosis of understanding pathogenesis of tongue cancer.

Secondarily stabilized dental implants: an alternative to sinus grafting--early clinical results of 63 consecutively placed implants.

PURPOSE: A standard dental implant modified with an apical cross-screw was studied clinically in the posterior maxilla in a trial of 63 sinus-penetrating implants. PATIENTS AND METHODS: Twenty-five patients who had cross-screw implants placed in the atrophic posterior maxilla were followed for up to 3 years. RESULTS: Of 63 implants placed, 5 implants failed over a 4-year study period for a 92.1% success rate. Despite the implant body penetrating into the sinus cavity, no long-term complication resulted. CONCLUSION: Threaded dental implants that were stabilized secondarily with a cross-screw maintained stability and did not disturb sinus cavity health over a 3-year period.

Plasmacytoma in the temporomandibular joint: a case report.

We report a case of a 64-year-old patient in whom limitation of mouth opening was the presenting symptom of plasmacytoma. Intra-oral biopsy confirmed a plasma-cell tumour, with no sign of extension on imaging. He was treated with radiotherapy (4000 cGy) and followed up. The diagnosis of solitary plasmacytoma of bone can be confirmed only when the presence of systemic disease has been excluded by clinical, biological, and radiological investigations. We think that the treatment should consist only of radiotherapy. Long-term follow-up is necessary because of the high risk of development of multiple myeloma, which may be delayed.

Periodontal care may improve endothelial function.

BACKGROUND: Periodontitis is a chronic, infectious, insidious disease of the tooth-supporting structures that causes a general inflammatory response. The aims of this study were to determine whether periodontitis is associated with endothelial dysfunction leading to cardiovascular events and whether proper management of periodontal disease would improve endothelial function and prevent cardiovascular events in the future. METHODS: Twenty-two patients (12 women, 10 men; 40+/-5 years old) took part in the study. All had severe periodontitis (without systemic disorders) and were all treated conservatively. Thirteen patients returned for a second visit after 3 months of treatment. Endothelial function and periodontal status were evaluated on entry into the study and 3 months following treatment. Ten age-matched, healthy volunteers without periodontal disease served as the control group. RESULTS: There was a significant difference between the patient group and the healthy controls: FMD% 4.12+/-3.96 vs. 16.60+/-7.86% (p=0.0000). Periodontitis improved significantly in all 13 patients who completed 3 months of treatment, and their endothelial function improved as well: FMD% 4.12+/-3.96% vs. 11.12+/-7.22% (p=0.007). No difference was found in FID% before and after 3 months of treatment: 20.97+/-10.66% vs.17.94+/-6.23% (p=NS). CONCLUSIONS: Periodontitis may be an insidious cause of endothelial dysfunction and cardiovascular events. Treating periodontitis can improve endothelial function and be an important preventive tool for cardiovascular disease.