Biomedical subjects

U Covani

Publications and source records attributed to U Covani.

10 recordsLinked to original sources

PubMed2002

Effects of CO2 laser treatment on fibroblast attachment to root surfaces. A scanning electron microscopy analysis.

BACKGROUND: The aim of this study was to analyze the CO2 laser effects on root surfaces affected by periodontal disease in comparison to scaling and root planing for fibroblast attachment. METHODS: Thirty single-rooted human teeth extracted because of advanced periodontal disease were included in this study. A total of 60 specimens, obtained from all selected teeth, were randomly assigned to 3 groups: 1) control (untreated); 2) hand scaling and root planing (SRP); or 3) laser (CO2 defocused pulsed) and ultrasonic scaling. All the specimens were incubated in Petri dishes with fibroblast suspension, and then observed by scanning electron microscopy (SEM). RESULTS: The control group showed the lowest number of attached cells, with no tightly attached fibroblasts. The laser plus scaling group showed the highest number of attached fibroblasts, with the tightly attached fibroblast prevailing. The laser-treated and scaled root specimens did not show any damage or morphologic alteration of the root surfaces. CONCLUSION: CO2 laser treatment in defocused, pulsed mode with a low power of 2W combined with mechanical instrumentation constitutes a useful tool to condition the root surface and increase fibroblast attachment to root surfaces.

Analysis of Variance↗

PubMed2002

Root surface morphological changes after focused versus defocused CO2 laser irradiation: a scanning electron microscopy analysis.

BACKGROUND: Many studies have observed damages to root surfaces treated by CO2 laser in continuous mode with a focused beam. The morphologic changes observed were always associated with temperature increase induced by high energy release. METHODS: The purpose of this study was to analyze by scanning electron microscopy (SEM) the effects of CO2 laser in 2 different modes on root surfaces. Study samples consisted of 30 extracted single-rooted periodontally compromised human teeth. Root specimens were randomly assigned to 3 groups: group A (12) treated with CO2 laser in continuous mode with a focused beam of 0.8 mm; group B (12) treated with CO2 laser in pulsed mode with defocused beam of 4 mm; and group C (6), untreated controls. RESULTS: Group A (continuous mode) showed severe damages to dentin surfaces such as craters and fissures. Group B (defocused mode) did not result in any damages to the root surfaces, showing flat and smooth surfaces with apparent fusion of the smear layer and dentinal tubules almost completely sealed. The untreated control group was characterized by irregular and amorphous surfaces with several shallow depressions. CONCLUSIONS: Although both laser modes resulted in changes to the treated root surface specimens, the changes resulting in a smooth surface from use of defocused pulsed beam may present an advantage in periodontal treatment.

Carbon Dioxide↗

PubMed1997

Periodontal tissue regeneration in beagle dogs after laser therapy.

BACKGROUND AND OBJECTIVE: Class III periodontal furcations still represent a challenge for the periodontist. Aim of this study was to test the effect of CO2 laser on the treatment of class III furcation defects. STUDY DESIGN/MATERIALS AND METHOD: Class III furcation defects 3 mm deep were surgically induced on mandibular premolars on six male Beagle dogs, for a total of 36 defects. After 6-8 weeks of plaque accumulation, the mean depth was 6.8 mm. Quadrants were randomly assigned to a) CO2 laser therapy (laser), b) Guided Tissue Regeneration (GTR) procedure using Gore-Tex Membranes, (Gore Tex, Flagstaff, Arizona, USA) and c) Scaling and Root planing (Sc/Rp). CO2 laser beam (El.En, Florence, Italy) was applied to the root surfaces in defocused pulsed mode at 2W, 1 Hz and a duty cycle of 6%, and on periodontal soft tissues at 13W, 40 Hz, and a duty cycle of 40%. Control quadrants received either GTR procedure or Sc/Rp. Mechanical oral hygiene was provided. At 6 months the animals were sacrificed. RESULTS: The laser group showed new attachment formation averaging 1.9 mm (sd +/- 0.5), whereas GTR and Sc/Rp showed 0.2 mm (sd +/- 0.4) and 0.2 mm (sd +/- 0.5) respectively, being the differences statistically significant between the laser group and both GTR and Sc/Rp groups (p < 0.005). CONCLUSION: CO2 laser treatment of class III furcation induced formation of new periodontal ligament, cementum and bone.

Alveolar Bone Loss↗

PubMed1997

Bone regeneration with a calcium sulfate barrier.

OBJECTIVES: Bone defects are a challenge for the dental clinician. As widely accepted in guided tissue regeneration, physically halting soft connective tissue proliferation into bone allows for bone regeneration. This concept is the "osteopromotion principle." The aim of this study was to assess the osteopromoting effect of calcium sulfate as a barrier. STUDY DESIGN: Forty male Sprague-Dawley rats were used. Mucoperiosteal flaps were raised bilaterally at buccal and lingual aspects of the mandible to expose the angles. Next, 5 mm through-and-through bony defects were created bilaterally. On the test side, sterile medical grade prehardened calcium sulfate disks were applied both lingually and buccally to cover the defect. The control side defects were left uncovered. All flaps were sutured closed. Observation times were 3, 9, 18, and 22 weeks. RESULTS: Histologic analysis demonstrated that at 3 weeks all test sites showed partial or complete bone healing. Similar findings were reported for all observation times. The control group showed no bone growth at 3 and 9 weeks and partial bone healing at 18 and 22 weeks. CONCLUSIONS: This study indicates that calcium sulfate barriers can exclude connective tissues, allowing bone regeneration during healing.

Alveolar Process↗

PubMed1996

New directions in surgical endodontics; immediate implantation into an extraction site.

Endodontic surgical procedures may reveal compromising factors that indicate a modification of the treatment (e.g. tooth extraction, root amputation, etc.). To take advantage of the osseous height and width, as well as the natural tooth angulation, immediate placement of implants after extraction is a reasonable alternative treatment. In this study, 32 titanium alloy implants were inserted immediately after extraction of teeth diagnosed during endodontic surgery as having root fractures, perforations, or endodontic-periodontal complications. After 4 to 6 months of osseointegration, only one implant failed to integrate, and the remaining implants were prosthetically restored. Sixteen months after occlusal loading, bone loss was approximately 1.5 mm for the 31 implants remaining. It seems that the immediate placement of implants following tooth extraction due to endodontic complications is a reliable procedure.

Adult↗

PubMed1996

Topographic distribution of subgingival plaque along root surfaces of human periodontally diseased teeth. A descriptive study.

The purpose of this study was to characterize the topographical distribution and organization of subgingival plaque in periodontally diseased teeth. 26 extracted teeth were fixed and processed for undecalcified histological evaluation. The sections were cut perpendicular to the long axis of the tooth and analyzed by phase-contrast microscopy. The coronal portion of the analyzed roots showed a dense accumulation of filamentous forms, fusiform rods, coccoid forms and loosely aggregated spirochetes. The middle and apical portions showed a non-uniform distribution of the microflora, with microorganisms representing all the known morphotypes. Furthermore, plaque was detected below undisturbed periodontal fibers, indicating that plaque not only forms apically, but also in a lateral direction, penetrating and colonizing below areas where periodontal fibers are inserted into the root surface.

Adult↗

PubMed1994

Generalized gingival enlargement due to accumulation of amyloid-like material.

Hyaline or amyloid-like substances may be seen in several oral lesions. Some of these originate from epithelial cells and some from connective tissue components. In this study, amyloid-like material causing gingival enlargement in three patients, with eyelid involvement in two, was examined using histochemistry, immunohistochemistry and electron microscopy. These accumulations did not share the classical features of amyloid such as green birefringence under polarized light after Congo red staining. Our findings suggest that epithelial degeneration plays an important role in the pathogenesis of these amyloid-like accumulations. These substances may be the result of defective amyloidogenesis and our cases may represent an oral counterpart of ligneous conjunctivitis or colloid milium of the skin.

Adolescent↗

PubMedDate not supplied

Immediate one-stage postextraction implant: a human clinical and histologic case report.

The placement of an implant immediately after tooth extraction may have the following advantages: reduction in morbidity, treatment time, and treatment costs; preservation of the residual ridge width and height; optimal esthetic result; and easier definition of implant position. The aim of the present study was the presentation of a human clinical and histologic report involving a nonsubmerged implant placed in a mandibular postextraction site and removed because of persistent pain. At low-power magnification, it was possible to see that newly formed bone with wide osteocyte lacunae was present around the implant. A 1.5-mm sulcular epithelium was visible on one side of the implant, with a 0.5-mm epithelial attachment. The thickness of the supracrestal connective tissue was 3.2 mm. This connective tissue was dense, had few cells, was well vascularized, and showed no evidence of an inflammatory infiltrate. Under polarized light, it was possible to observe that the connective fibers were arranged perpendicular to the implant surface and that these fibers became parallel near the implant. These results show that human immediate postextraction implants can have a high percentage of bone-implant contact.

Alveolar Process↗

PubMedDate not supplied

Simultaneous implant placement and vertical ridge augmentation with a titanium-reinforced membrane: a case report.

The present report demonstrates a clinical approach to achieve vertical ridge augmentation around endosseous implants. Two implants were placed, leaving the threads exposed, in the atrophic mandibular right posterior quadrant of a male patient. Both implants were covered with a titanium-reinforced expanded polytetrafluoroethylene (e-PTFE) membrane. Second-stage surgery was performed 12 months after implant placement. Upon membrane removal, growth of mineralized tissue was observed around both implants, covering areas previously not covered by bone. Implants were then progressively loaded and restored. Titanium-reinforced e-PTFE membranes can be satisfactorily used for vertical augmentation of atrophic ridges.

Alveolar Ridge Augmentation↗

PubMedDate not supplied

[Magnetic attachments for implants in complete dentures].

In this research work we examine and apply to patients new types of technologies, describing advantages and disadvantages of using them. This osseointegrated implantation with magnetic prosthetic connection, allow to stabilize complete denture in patients suffering from serious atrophy.

Dental Implantation, Endosseous↗