Search

The aim of the present study is to perform a systematic review of the literature on the use of titanium grids for implant surgery before and simultaneously with implant placement and to assess the success rate of the procedure, as well as survival and success rates of implants placed in the regenerated areas.Medline was used to identify studies in English published from 1996 to 2011. An additional hand search was performed of the relevant journals and of the bibliographies of the papers identified. Articles retrieved by two independent authors were screened using specific inclusion criteria: randomized controlled trials (RCTs), controlled clinical trials, and prospective clinical studies regarding vertical and/or horizontal regeneration of the alveolar ridge using titanium grids, in association or not with biomaterials, before and simultaneously with implant placement.Six articles were selected, including a total of 79 patients, 87 titanium grids, and 141 implants. Twenty-four implants were placed simultaneously with titanium grids, and 117 implants were inserted after a period of 4 to 9 months. Titanium grids in combination with autogenous bone were used in 43 cases, 25 in combination with a mixture of autogenous bone and bone substitutes, 14 in association with bone substitutes, five using only titanium grids. The overall success rate of the regenerative procedures was 98.86%; the overall survival and success rates of implants were 100% and 93.2%, respectively.The main limit of the present systematic review is the scarcity of papers with an adequate and consistent methodology regarding the data collection and analysis and the lack of RCTs and large well-designed long-term trials. Survival and success rates of implants placed in the areas treated with titanium grids were comparable to those of implants placed in native, non-regenerated bone and of implants placed in bone regenerated with resorbable and non-resorbable membranes.

Background: The aim of the present randomized controlled clinical trial was to assess the bucco-lingual bone changes of implants immediately placed in fresh extraction sockets in association or not with porcine bone. Methods: Forty patients were included in the present study, and were randomly assigned to the control (n = 20) and test (n = 20) groups. Each patient received a single implant placed into an immediate extraction site of a molar or a first upper premolar with a flapless approach. In the control sites no grafting material was placed, while in the tests a deantigenated collagenated bone substitute of porcine origin was used to fill the gaps between the implant and the extraction socket. The bucco-lingual bone width was measured at different time points: at the time of surgery (T0), at 90 days (T1), at 110 days (T2) and after 6 months of masticatory function (T3). The values were statistically analyzed between and within the treatment groups (p0.05). Results: All the implants were osseointegrated. Four control implants were excluded from the analysis due to the exposure of the coronal portion of the fixture. At T1, T2 and T3, statistically significant differences were found by comparing the mean width of the bucco-lingual bone between control and test groups. The mean values decreased during the observation period in both groups; statistically significant differences within controls were detected at T1, T2 and T3, and at T2 and T3 within tests. Conclusions: The outcomes of present study suggested that porcine bone enabled to avoid bucco-lingual crestal bone changes in implants immediately placed in fresh extraction sockets.

Stability of peri-implant crestal bone plays a relevant role relative to the presence or absence of interdental papilla. Several factors can contribute to the crestal bone resorption observed around two-piece implants, such as the presence of a microgap at the level of the implant-abutment junction, the type of connection between implant and prosthetic components, the implant positioning relative to the alveolar crest, and the interimplant distance. Subcrestal positioning of dental implants has been proposed to decrease the risk of exposure of the metal of the top of the implant or of the abutment margin, and to get enough space in a vertical dimension to create a harmoniously esthetic emergence profile.The present retrospective histologic study was performed to evaluate dental implants retrieved from human jaws that had been inserted in an equicrestal or subcrestal position. A total of nine implants were evaluated: five of these had been inserted in an equicrestal position, whereas the other four had been positioned subcrestally (1 to 3 mm).In all subcrestally placed implants, preexisting and newly formed bone was found over the implant shoulder. In the equicrestal implants, crestal bone resorption (0.5 to 1.5 mm) was present around all implants.The subcrestal position of the implants resulted in bone located above the implant shoulder.

The aim of the present study in humans was to conduct a comparative immunohistochemical evaluation of vascular endothelial growth factor (VEGF) and nitric oxide synthase (NOS) expression, inflammatory infiltrate, proliferative activity expression, and microvessel density (MVD) in peri-implant soft tissues of titanium and zirconium oxide healing caps.Five patients, three men and two women (aged 30 to 66 years; mean: 49 years), participated in this study. All patients received dental implants that were 3.8 mm in diameter and 11 mm in length. All implants were left to heal in a non-submerged (single-stage) mode. Healing caps (3.8 mm in diameter and 3.0 mm in height) were inserted in all implants. Half of the implants were supplied with standard, prefabricated caps of commercially pure titanium, whereas the other half were provided with test zirconium oxide caps. After a 6-month healing period, a gingival biopsy was performed with a circular scalpel (5.5 mm in diameter) around the healing caps of both groups, without unscrewing or removing the healing caps. The dimensions of the gingival biopsies were 1.7 mm (5.5-3.8 mm) in thickness and 3 mm in height.Statistically significant differences were found in the microvessel density between titanium and zirconium oxide healing caps and group II (Por = 0.0001). Statistically significant differences were likewise found in the low and high intensities of NOS1, NOS3, and VEGF (Por = 0.0001). In conclusion, the high intensity of NOS1, NOS3, and VEGF were mostly expressed in the titanium group, whereas the low intensity of NOS1, NOS3, and VEGF were mostly expressed in the zirconium oxide group.In our specimens, the inflammatory infiltrate was mostly present in the titanium specimens. Their extension was much larger than that of the zirconium oxide specimens. Higher values of MVD were observed in the titanium specimens (29.1 versus 15.8). In addition, a higher expression of VEGF intensity was observed in the peri-implant tissues of titanium healing caps, whereas predominantly lower expressions of VEGF intensity were noted around the zirconium oxide healing caps. The Ki-67 expression was higher in the titanium specimens. All these data revealed that the tissues around titanium healing caps underwent a higher rate of inflammation-associated processes, most probably correlated to the higher inflammation processes observed in these tissues. A higher intensity expression of NOS1 and NOS3 was recorded in the tissues around titanium, whereas, on the contrary, a lower intensity of expression was found in the tissues around zirconium oxide specimens. These latter data indicate that the higher expression of these two mediators could be correlated to the higher amount of bacteria present around the titanium samples.

Mucosal malignant melanoma of the of the head and neck is a rare neoplasm, accounting for about 0.2% of all melanomas. We present the clinopathological findings of a case.An 83-year-old woman presented with a dark reddish pigmented lesion which had appeared 3 years previously.Clinical examination revealed a sessile lesion, 1.5 cm in diameter, located on the vestibular maxillary gingiva next to the first molar area. Microscopic analysis of the neoplasm showed epithelioid cells with prominent nucleoli aggregated in solid nests. Cytoplasmic melanin pigmentation was present. The neoplastic cells were positive for HMB-45 and S100 protein. The final histologic diagnosis was primary malignant melanoma of the gingiva. Physical examination and a computerized tomography scan of the neck, liver, and lungs ruled out the possibility of occult melanoma lesions elsewhere in the body.The prognosis for patients with oral malignant melanoma is extremely poor. Earlier recognition of this condition simplifies treatment and greatly improves the prognosis for these patients.

Two-piece implants present gaps and cavities between the implant and the abutment, and these hollow spaces can act as a trap for bacteria. The aim of the present in vitro study was to evaluate the migration of two different microbial species from the inside to the outside of the implant-abutment assembly in three different connection types.A total of 30 implants (10 implants per group) were used. The implants presented a screwed trilobed connection (group 1), a cemented connection (group 2), and an internal conical connection (group 3). The inner parts of five implants, per group, were inoculated with Pseudomonas aeruginosa suspension and the remaining five implants, per group, with Aggregatibacter actinomycetemcomitans. The penetration of bacteria into the surrounding solution was determined by the observation of turbidity of the broth.In group 1, bacterial contamination was found in six of 10 implants. In group 2, no contaminated samples were found. In group 3, bacterial contamination was found in one implant of 10. Statistically significant differences were detected between group 1 versus group 3 (P0.05) and between group 1 versus group 2 (P0.01), whereas no significant differences were found when comparing group 2 versus group 3 (P0.05).The present study confirms previous results about the hermeticity of the cement-retained implant-abutment assembly, the very low permeability to bacteria of the conical implant-abutment connection, and the high prevalence of bacterial penetration of screw-retained implant-abutment assemblies.

At present, only some studies have dealt with immediate loading of unsplinted implants supporting mandibular overdentures. The aim of this prospective study is to evaluate treatment outcomes of mandibular overdentures supported by four one-piece, unsplinted, immediately loaded, direct laser metal-forming (DLMF) implants by assessing implant survival rate, implant success, marginal bone loss, and prosthetic complications.A total of 96 one-piece DLMF implants were inserted in the edentulous mandible of 24 patients. Four implants were placed in each edentulous mandible. Immediately after implant placement, a mandibular overdenture was connected to the implants. At 1-year follow-up, clinical, radiographic, and prosthetic parameters were assessed. Success criteria included absence of pain, suppuration, and implant mobility; absence of continuous peri-implant radiolucency; and distance between the implant shoulder and the first visible bone contact1.5 mm.After a 1-year loading time, the overall implant survival rate was 98.9%, with only one implant lost. Among the surviving 95 implants, two did not fulfill the success criteria; therefore, the implant success rate was 97.8%. The mean distance between the implant shoulder and the first visible bone contact was 0.28 ± 0.30 mm (95% confidence interval, 0.24 to 0.32). Some prosthetic complications were reported.Based on the present results and within the limits of this study, the immediate loading of four unsplinted DLMF implants by means of ball attachment-supported mandibular overdentures seems to represent a safe and successful procedure.

In periodontal tissues, angiogenesis seems to be important for the maintenance of healthy tissues and in periodontal diseases. Angiogenesis is regulated through a complex interplay of molecular signals mediated by growth factors involving extracellular matrix remodeling, endothelial cell migration and proliferation, capillary differentiation and anastomosis. However, the influence of angiogenesis in the development, progression, and healing of periodontal lesions is currently under investigation. This immunohistochemical study evaluates the expression of vascular endothelial growth factor (VEGF), microvessel density (MVD), nitric oxide synthase (NOS) 1 and 3, and Ki-67 in gingival tissues of patients with aggressive and chronic periodontitis.Twenty-seven human gingival biopsies were taken from patients with chronic periodontitis (n = 14 patients), generalized aggressive periodontitis (n = 6 patients), and healthy periodontia (n = 7 patients). The specimens were immunohistochemically stained for VEGF, MVD, NOS 1 and 3, and Ki-67.The levels of VEGF, MVD, NOS 1 and 3, and Ki-67 were found to be significantly different among groups (P0.001). Patients with aggressive periodontitis had higher levels of these markers compared to those in patients with chronic periodontitis and healthy patients.The analysis demonstrates a higher expression of all immunologic markers particularly in subjects with aggressive periodontitis. In summary, the data from this pilot investigation suggests that VEGF is an important factor in the pathogenesis of the aggressive and chronic forms of periodontitis.

Background: The aim of the present study is a comparative evaluation of inflammatory infiltrate, microvessel density, vascular endothelial growth factor, nitric oxide synthase, and proliferative activity in soft tissues below intraorally welded titanium bars. Methods: Twenty-two patients participated in this study. All patients carried immediately loaded one-stage titanium implants splinted with intraorally welded titanium bars. Each patient underwent two gingival biopsies, a control biopsy harvested from an area of mucosa 5 mm away from the titanium bar and a test biopsy from the mucosa below the titanium bar, which were histologically and immunohistochemically processed. Results: No fractures or radiographically detectable alterations of the welded frameworks were present. In all the cases examined, the average of the modified plaque index was 1, no suppuration or bleeding on probing was present, and probing depth was £3 mm. However, the immunohistochemical analysis revealed some differences. The inflammatory infiltrate was mostly present in test sites and its extension was much larger than in control sites. Statistically significant differences were found in microvessel density and Ki-67 expression among control and test groups (P