Debris production in bovine bone during implant site preparation. A comparative in vitro study: ultrasonic and drilling procedures.

The aim of this study was to compare the size and shape of bone fragments produced by the ultrasonic and drilling procedures in implant site preparation. Six pieces of rib selected as experimental animal model of 15 cm in length and at least 13 mm of thickness were used. The samples were treated and divided into 2 groups as follows: group A (GA) ultrasonic implant site preparation technique; group B (GB) traditional surgical drill technique. Ultrasonic implant site preparation (GA) was carried out using a sequence of progressive diameter (1.00 mm, 2.00 mm and 3.00 mm) conical inserts at a depth of 10 mm. Standard drill implant site procedure (GB) was carried out with a sequence of 1.00 mm, 2.00 mm, and 3.00 mm cylindrical twist drills, for preparing an implant site at a depth of 10 mm. From each group bone fragments (0.1 gr) were collected from both cortical and cancellous bone preparation and their dimensions were evaluated by optic microscope analysis. The bone debris dimensions procured by cortical bone of Group A and Group B were, respectively, 0.14×0.16 mm (±0.13) and 1.15 ×0.92 mm (±0.68). The bone debris dimensions procured by cancellous bone of Group A and Group B were, respectively, 0.15×0.10 mm (±0.10) and 1.98×1.27 mm (±0.94). Ultrasonic implant site preparation technique was able to micronize bone and to remove all debris with cooling system. Surgical drills tend to fracture bone, creating a weaker structure and fragments of larger size, which remain in considerable quantity over bone walls during site preparation. Within the limits of the present study, the ultrasonic implant preparation was able to produce reduced bone sediments and a clear bed implant favoring osseointegration.

Treatment of a peri-implantitis defect using a mini-invasive surgical approach (MISA) and deproteinized bovine bone mineral with 10% collagen: a case series.

This pilot study evaluates the effectiveness of the Mini-Invasive Surgical Approach (MISA) in the treatment of peri-implantitis defect. MISA is based on the use of the deproteinized bovine bone mineral with 10% collagen in combination with a minimal flap. The main principle is the elevation of a flap to access to the peri-implantitis defect only on one side (palatal aspect), leaving the opposite site intact. The study was designed as a non-controlled, non-randomized pilot study. In 10 consecutive subjects, 10 implants with diagnosis of perimplantitis were selected. In all the treated sites, primary closure was obtained at completion of the surgical procedure. No relevant pain, edema and hematoma were noted. The reported surgical approach resulted in significant clinical and radiographic improvements while limiting patient morbidity. After 1-year follow-up minimal mucosal recession, probing depth reduction and radiographic bone gain were noted.

Extraction of mandibular third molars: proposal of a new scale of difficulty.

We evaluated the accuracy of a new scale of surgical difficulty for the extraction of impacted mandibular third molars, which includes consideration of previously underestimated variables. Two hundred patients with impacted third molars were enrolled, and a preoperative clinical and radiographic assessment of difficulty was made by an oral surgeon using the new index. Five oral surgeons with similar degrees of experience then evaluated the surgical difficulty during operation. The kappa test and weighted kappa were used to evaluate the level of agreement between the preoperative and postoperative evaluations. This was 0.73, which indicated a substantial concordance between the preoperative and postoperative assessments of difficulty indicated by the new scale. The linear weight of kappa was 0.8 and the quadratic weight 0.87. We recommend this new scale of surgical difficulty for the extraction of impacted third molars for use in clinical practice.

Analysis of occlusal stresses transmitted to the inferior alveolar nerve by multiple threaded implants.

BACKGROUND: Potential nerve injury or loss of sensation can occur after mandibular implant placement or loading. To avoid this type of damage, it is critical to determine the proper distance from implants to the mandibular nerve. Hence, the purpose of this study is to use biomechanical analyses to determine the safe distance from multiple implants to the inferior alveolar nerve. METHODS: Using the boundary element method, a numerical mandibular model was designed to simulate a mandibular segment containing multiple threaded fixtures. This model allows assessment of the pressure, as induced by occlusal loads, on the trigeminal nerve. Such pressure distribution was evaluated against different distances from the fixtures to the mandibular canal, against the possible lack of the central fixture in a three-abutment configuration, and against different levels of implant osseointegration. All the simulations considered a canal that is orthogonal to the implant axis. RESULTS: Nerve pressure increased quickly when the implant-canal distance decreased in the range studied. Lack of the central implant to support the central abutment caused major increases in nerve pressure. CONCLUSIONS: This study suggests a minimal implant-canal distance of 1 mm to prevent inferior alveolar nerve damage caused by three connected implants. For clinical safety, an additional 0.5 mm is recommended as a cushion, so a 1.5-mm minimal distance should be planned to avoid potential nerve injury.

Use of piezosurgery device in management of oral surgery complications: clincal case and clinical experience report.

The root displacement into the maxillary sinus could be a complication of oral surgery in the upper jaw. In these cases, the root removal is needed in order to avoid the occurrence of sinus pathologies. Piezosurgery techniques could assure a safer management of such complications, because of the clear surgical visibility and the selective ability of cut. The aim of this article is to present a case of oral surgery complication (root displacement in the right maxillary sinus), in which piezosurgery technique helped for a correct and safe clinical management, allowing to reduce the soft tissue damage.

Frenulectomy: proposal of a new surgical approach and case report.

The frenula of the oral cavity represent the insertion of perioral muscles in jaws, consisting of a fold of the triangular fibro-connective tissue covered with mucous membrane and usually inserted at the mucogingival line. The purpose of this work, after a review of literature, was to provide the clinical signs above the median frenum removal order for the orthodontic closure of a interincisor diastema and to present a new surgical technique.

Surfactant protein B and RAGE increases in the plasma during cardiopulmonary bypass: a pilot study.

Surfactant derived protein B (SPB) and plasma receptor for advanced glycation end products (RAGE) have been proposed as markers of lung injury. The former is produced specifically by pneumocytes while RAGE production is present in several body tissues. Cardiopulmonary bypass (CPB) generates a transient lung injury. We measured SPB and RAGE in plasma before surgery and after CPB, as well as 24 h and 48 h later. We analysed plasma samples from 20 subjects scheduled for elective coronary artery bypass grafting. We performed a quantitative analysis of plasma levels of RAGE and SPB mature form (8 kDa) by ELISA and a semi-quantitative analysis of SPB immature form (~ 40 kDa) by Western blotting. Surgery procedures were uneventful. After CPB RAGE median (75th-25th interquartile difference) increased from 633 (539) pg·mL⁻¹ to 1,362 (557) pg·mL⁻¹ (p < 0.01), while mature SPB increased from 5,587 (3,089) ng·mL⁻¹ to 20,307 (19,873) ng·mL⁻¹ (p < 0.01). RAGE and mature SPB returned to normal values within 48 h. This behaviour was confirmed when RAGE and SPB were normalised for protein content. Parallel changes were observed for immature SPB. Plasma RAGE and SPBs are sensitive and rapid markers of lung distress.

Clinical difficulties in diagnosis: a rare case of lipoma of the floor of the mouth.

Lipomas are soft tissue mesenchymal neoplasms that rarely occur in the oral and maxillofacial region. Their incidence in the floor of the mouth is very low. The authors present the case of a lipoma of the floor of the mouth, the diagnosis of this lesion was challenging as many clinical signs mimicked the appearance of a common ranula. Also the ultrasound imaging findings were not decisive and only during the operation the yellowish, solid and lobulated aspect of the lesion directed the surgeon to the correct treatment: a block resection of the mass was performed under local anesthesia with no complications. The patient remained asymptomatic with no evidence of recurrences in the postoperative follow-up period of 24 months. Histopathologically, the lesion was classified as a lipoma, a diagnosis based on the presence of mature adipose tissue with no cytologic atypia, subdivided by rare and thin septa of fibrous tissue with the presence of few blood vessels. The case reported highlights the difficulties in diagnosing lesions in the floor of the mouth and the necessity of including rare conditions like lipoma in the differential diagnosis.

Glutathione, vitamin E and oxidative stress in coronary artery disease: relevance of age and gender.

BACKGROUND: Observational studies suggest that low levels of antioxidants are associated with high risk for coronary artery disease (CAD). We investigated whether the biomarkers of oxidative balance undergo the same modifications in all CAD patient groups, regardless of gender and age. MATERIALS AND METHODS: One hundred sixty-eight CAD patients and 107 healthy controls were assayed for plasma levels of reduced glutathione (GSH), alpha- and gamma-tocopherol (alpha- and gamma-T) as endogenous antioxidants. A damage score (DS), representative of oxidative stress status, was calculated. ANCOVA models were used to test the association between antioxidants, DS and CAD and its modulation by age and gender. RESULTS: The DS was higher in CAD than in controls. GSH levels, were lower in CAD patients (mean +/- SEM: 57.61 +/- 1.87 micromol 10 g(-1) haemoglobin vs. 68.55 +/- 2.23 in controls, P < 0.0006) in males and in older subjects. Levels of other antioxidants exhibited a complex pattern. Overall, no difference was found in alpha- and gamma-T contents between CAD and controls, but lower alpha-T values were observed in CAD females. A significant interaction between CAD status and gender was observed (P = 0.003). CONCLUSIONS: Our study shows that the involvement of antioxidants in CAD is related to patients' characteristics. These findings may be relevant in planning antioxidant therapies.

Analysis of the occlusal stress transmitted to the inferior alveolar nerve by an osseointegrated threaded fixture.

BACKGROUND: Altered sensation can occur after the placement or loading of mandibular implants. Limited evidence exists with regard to the proper distance between the implant and the mandibular nerve to ensure the nerve's integrity and physiologic activity. The proper distance should come from evaluation of clinical data as well as from biomechanical analyses. METHODS: A numeric mandibular model based on the boundary element method was created to simulate a mandibular segment containing a threaded fixture so that the pressure on the trigeminal nerve, as induced by the occlusal loads, could be assessed. Such pressure distributions were evaluated with different distances of the fixture from the mandibular canal and considering different bone densities. Although all simulations considered a canal that was orthogonal to the implant axis, in one case, the effects of an inclined canal were analyzed. RESULTS: The nerve pressure increased rapidly with a bone density decrease. A low mandibular cortical bone density caused a major nerve pressure increase. CONCLUSION: Our study suggested a distance of 1.5 mm to prevent implant damage to the underlying inferior alveolar nerve when biomechanical loading was taken into consideration.