PubMed Health⌕ Search

Biomedical subjects

J S López-Arranz

Publications and source records attributed to J S López-Arranz.

9 recordsLinked to original sources
PubMed2006

Histomorphometric evaluation of guided bone regeneration around implants with SLA surface: an experimental study in beagle dogs.

The aim of this study was to evaluate the efficacy of collagen membranes, either alone or combined with a human demineralized freeze-dried bone allograft (DFDBA) or natural bovine bone graft, in bone defects around dental implants with an SLA (sand-blasted, large grit, acid-etched) surface. The experiments were carried out in three beagle dogs using a split-mouth design. On one side of the jaw, three implants were placed and intra-bony defects were created and covered with a collagen membrane, randomly combined in two of the defects with human DFDBA or inorganic bovine bone graft. A control implant, without membrane covering or defect filling, was also placed. On the other side of the jaw, three implants were placed and the bone defects were treated in a similar fashion, but without membrane covering. The studied variables were the percentage of bone-to-implant contact within the limits of the initial bony defect and percentage of the original bony defect occupied by bone tissue. Although no statistically significant differences were found in this study between the membrane and nonmembrane groups, bone defects augmented with anorganic bovine bone and membranes showed the most promising results from a histological and histomorphometric perspective.

Animals↗
PubMed2001

Oral squamous cell carcinoma of the mandibular region: A survival study.

BACKGROUND: Oral squamous cell carcinomas (SCC) of the mandibular region present the lowest survival rates of the whole oral cavity. The purpose of this analysis was to evaluate the prognostic significance of several diagnostic and therapeutic variables in the survival rates of these carcinomas. METHODS: Forty-nine patients with oral cancers were treated by primary site surgery, involving mandibular resection in all cases. Thirty-one patients underwent postoperative adjuvant radiotherapy. RESULTS: Overall mean survival time and 5-year survival rate were 56.5 months and 44%, respectively. Patients in stages III and IV showed a statistically significant (p = .01) lower survival rate than those in stage II, and positive surgical margins had an adverse effect on survival (p = .03). No differences were found between patients treated by marginal or segmental mandibulectomy. CONCLUSIONS: Among the prognostic predictors studied, only the status of the surgical resection margin (odds ratio, 5.7) and tumor stage (III and IV vs II showed odds ratios of 2.1 and 3.6, respectively) affected the prognosis for SCC of the mandibular region. Tumor site was not associated with prognosis but was related with the probability that surgical margins were involved.

Carcinoma, Squamous Cell↗
PubMed2000

Tissue regeneration in bone defects adjacent to endosseous implants: an experimental pilot study.

Extraction socket defects or alveolar ridge defects may limit or restrict placement of implants. The present study assessed the efficacy of inducing bone formation with demineralized freeze-dried bone (DFDB), osteoinduction with hydroxyapatite (HA), and guided bone regeneration with expanded polytetrafluoroethylene (e-PTFE) in bone defects adjacent to endosseous implants in an animal model. Twenty-four implants were placed in the long bones of 3 pigs. After preparation of 24 cylindric acute defects adjacent to the coronal 5 mm of each implant, 18 of the defects were treated by DFDB, HA, or e-PTFE. The 6 remaining defects healed spontaneously with no treatment (controls). In each pig, one tibia received 4 commercially pure titanium screw implants (3.75 mm x 15 mm), while the contralateral tibia received 4 HA-coated cylindric implants (3.25 mm x 15 mm). Bone formation in response to the 3 treatments and control cases was evaluated using computer-assisted densitometric image analysis. The results showed that a higher density of tissue formed under e-PTFE membranes. A significantly greater increase in bone density was noticed in bone defects treated with an e-PTFE membrane vs DFDB (P = 0.04), in e-PTFE vs control sites (P = 0.04), and in defects treated with HA vs DFDB (P = 0.04) in HA-coated implants. In titanium implants the differences observed were not significant. It was also observed that bone regeneration in defects treated with HA differs with the type of implant used (titanium vs HA-coated implants), but such differences were not significant.

Analysis of Variance↗
PubMed1999

Pleomorphic adenoma of the salivary glands: prospective clinicopathologic and flow cytometric study.

BACKGROUND: Primary surgery is the appropriate treatment for most pleomorphic adenomas of the salivary glands. However, no reliable criteria have been established to predict tumors with aggressive features. METHODS: In 44 patients treated for salivary pleomorphic adenoma, clinicopathologic features and flow cytometric findings were recorded. S-phase fractions were classified as low (0%-1%), intermediate (1.1%-5%), and high (>5%). The relationship between clinicopathologic parameters and flow cytometric DNA analysis was assessed with the Pearson's correlation coefficient. RESULTS: The mean tumor size was 24.4 mm. Microscopically, myxoid structures predominated in 61.4% of cases. Only five specimens showed high S-phase fractions. All samples were DNA diploid (mean coefficient of variation 3.2%). S-phase fraction and tumor size correlated significantly (r = 0.73, P = 0.003). Two patients with recurrent tumors had high S-phase fractions both on the first resected specimens and at the time of the second operation. CONCLUSIONS: The S-phase fraction may be a valuable predictor of aggressive behavior in salivary pleomorphic adenomas. High S-phase fractions were associated with higher tumor size and a greater tendency to recur.

Adenoma, Pleomorphic↗
PubMed1998

Bone regeneration after radicular cyst removal with and without guided bone regeneration.

In order to determine the degree of bone regeneration after removal of radicular cysts using guided bone regeneration (GBR), a prospective, controlled and randomized clinical study was performed. Thirty patients with radicular cysts were divided into three groups. One group, the control group (n=10 patients), was treated by enucleation and primary closure. The other two groups were treated by enucleation and primary closure but GBR was used in addition, using a resorbable membrane (n=10) and a nonresorbable membrane (n=10). The membranes were fixed with nonresorbable Memfix System screws. The residual volume and the density of the newly formed tissue was measured by computer-assisted tomography and computer-assisted digital image analysis before enucleation and three and six months postoperatively. No statistical significance was found in density and residual volume between the three treatment groups after six months. These results suggest that GBR using membranes does not contribute to increased bone regeneration.

Adult↗
PubMed1997

Granular-cell tumours: an immunohistochemical study.

The granular cell tumour (myoblastoma, Abrikosoff's tumour) and the congenital epulis in newborns (Neumann tumour) are two lesions rarely found in the oral cavity, whose histogenetic origin is highly controversial. This work analyses using immunohistochemical techniques 15 cases of myoblastomas and two of congenital epulis with different mono- and poly-clonal antibodies. Positive immunostaining was found for S-100 protein and neuron-specific enolase in all the cases of myoblastoma, and for vimentin and carcinoembryonic antigen in some cases. No immunoreactivity was observed for any of the other 13 antibodies used in congenital epulis.

Actins↗
PubMed1997

Central epithelial odontogenic ghost cell tumour. A case report.

Central epithelial odontogenic ghost cell tumour, a neoplastic variant of calcifying odontogenic cyst, is a rare lesion with a very few cases published in the English literature. Histologically, the tumour consists of clusters of infiltrating odontogenic epithelium and ghost cells in varying numbers. We describe the first case of central epithelial odontogenic ghost cell tumour occurring in a pregnant woman and in which determination of bone densitometry in the preoperative panoramic radiographs has been performed. We have reviewed the literature available in English and compared it with our case.

Adult↗