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Biomedical subjects

C Clauser

Publications and source records attributed to C Clauser.

At least 19 recordsLinked to original sources
PubMed2000

The effect of chlorhexidine mouthrinses on early bacterial colonization of guided tissue regeneration membranes. An in vivo study.

BACKGROUND: Different membrane materials accumulate varying amounts of bacteria when exposed in the oral cavity, due to their textural and structural surface characteristics. The aim of the study was to evaluate the effect of chlorhexidine mouthrinses on the in vivo early bacterial colonization of 3 different guided tissue regeneration membrane materials. METHODS: Rectangular-shaped strips cut from 3 periodontal membranes (expanded polytetrafluoroethylene, polyglactin 910, and polylactic acid) were glued to removable devices adapted to the 2 upper quadrants in 8 dental students. In each student 1 quadrant was randomly selected as test side while the other served as control side. The experiment was divided in 2 phases: in the first phase plaque accumulation was followed for 4 hours while the second accumulation was followed for 24 hours. During the 4-hour experiment, students rinsed the test device twice (immediately following device application and after 2 hours) with 0. 12% chlorhexidine solution. The control device was rinsed with saline. In the second phase, students rinsed the test device with chlorhexidine and the control devices with saline 3 times (after device application and at 8 and 16 hours). Both the 4-hour and the 24-hour specimens were processed for scanning electron microscopy analysis. Fifty-four fields (at 200x magnification) were randomly selected and analyzed on each strip. Magnification was increased to determine the presence and morphotype of bacteria. The presence or absence of bacteria was assessed in a binomial fashion: the field was bacteria-positive when bacteria constituted the deposits covering the membrane surface. The microscopic field was negative (bacteria-negative) when no bacteria were observed. Bacteria-positive fields showing rods and filaments as prevalent morphotypes were recorded as rod-positive fields. RESULTS: The results of data analysis suggest that bacterial contamination of membrane materials is significantly reduced by treatment with chlorhexidine. They also suggest that other variables affect plaque accumulation as well; i.e., the time allowed (4 versus 24 hours) and the different membrane materials. The interaction between these 2 variables is also highly significant, thereby indicating a different rate of plaque accumulation on different materials, irrespective of the treatment with chlorhexidine. CONCLUSIONS: It was concluded that chlorhexidine mouthrinses may be effective in reducing and delaying the early bacterial accumulation on membrane materials although they are not able to fully prevent it. Membrane surface characteristics seem to be a more critical factor than the use of chlorhexidine, in influencing bacterial adhesion and colonization of barrier materials.

Adult↗
PubMed1999

Topical and systemic antimicrobial therapy in guided tissue regeneration.

BACKGROUND: Bacterial contamination of membrane material negatively affects healing after guided tissue regeneration (GTR) procedures; conversely, flap connective tissue integration on barrier material improves the clinical outcomes. The objective of this study was to evaluate the effect of topical application of antibiotics on: 1) clinical outcomes of GTR surgical procedures using titanium reinforced expanded polytetrafluoroethylene (ePTFE) periodontal membrane; 2) bacterial colonization of membrane material; and 3) flap connective tissue-membrane integration. METHODS: Fifty-six deep interproximal bony defects were treated with GTR surgical procedures using titanium reinforced ePTFE periodontal membranes. Patients were randomly assigned to 1 of the 2 antimicrobial treatment groups: the test group received weekly topical application of 25% metronidazole gel and the control group received systemic antibiotics (amoxicillin plus clavulanic acid 1 g/day for 14 days). Clinical outcomes were assessed at 1 year; the amount of bacterial contamination and connective tissue integration on membrane material was evaluated at time of membrane removal by means of a morphological (SEM) method. RESULTS: No statistically significant difference was found between test and control groups in terms of clinical attachment (CAL) gain (baseline CAL - 12 months CAL; P = 0.2) and probing depth (PD) reduction (baseline PD - 12 months PD; P = 0.6). A greater increase in gingival recession (REC) (12 months REC - baseline REC) was found in the test group compared to the control group (P = 0.003). The SEM analysis revealed no statistically significant (t test) difference between test and control groups in the number of fields positive to integrated connective tissue (P = 0.82), while the number of fields positive to bacteria was statistically higher (P < 0.001) in the control group. CONCLUSIONS: Local antibiotic administration is more effective than systemic use in preventing membrane contamination, but it does not improve clinical outcomes due to an interference of the vehicle (gel) with gingival tissues which may reduce the potential benefits derived from better control of the bacterial load.

Administration, Topical↗
PubMed1999

Localized soft tissue ridge augmentation at phase 2 implant surgery: a case report.

A case of congenitally missing maxillary lateral incisors is presented to illustrate a modification of Abrams's roll technique. Buccal releasing incisions are avoided by using an intrasulcular incision on the adjacent teeth. The tissue overlying the cover screw is transferred between the buccal cortical bone and the buccal masticatory mucosa, thus correcting the localized buccal ridge atrophy.

Adult↗
PubMed1998

Early bacterial accumulation on guided tissue regeneration membrane materials. An in vivo study.

The aim of the study was to compare the in vivo early bacterial plaque colonization of 3 different guided tissue regeneration (GTR) membrane materials using a morphological (scanning electron microscope) method. Rectangular-shaped strips were cut from 3 periodontal membranes (expanded polytetrafluoroethylene, polyglactin 910, and polylactic acid) and glued to the buccal aspect of removable acrylic devices, which were applied to the molar-premolar region of the upper quadrants in 8 dental students. Each device held 3 strips: one ePTFE, one polyglactin 910, and one polylactic acid. The surface roughness of each membrane material was measured by means of a laser profilometer. During a 24-hour period, the students had to refrain from any oral hygiene procedures and did not use chlorhexidine mouthrinses. In each subject, one device was removed after 4 hours and the other after 24 hours. After removal, the devices were placed in a 2.5% gluteraldehyde solution to fix the membranes, which were then processed for SEM analysis. Fifty-four microscopic fields (at 200x magnification) were randomly selected and analyzed in each strip. Magnification was increased to determine the presence of bacterial morphotypes. The presence or absence of bacteria was assessed in a binomial fashion. In such a system, the field was bacteria-positive when bacteria constituted the deposits covering the surface of the membrane. The microscopic field was considered bacteria-negative when no bacteria were present. Bacteria-positive fields showing rods and filaments as prevalent bacterial morphotypes were recorded as rod-positive fields. A different pattern of plaque accumulation was demonstrated on different membrane materials. The 4-hour results indicated a statistically significant difference (P = 0.008, ANOVA) in the proportion of bacteria-positive fields among the 3 membranes; a greater amount of bacteria was demonstrated on the ePTFE membrane compared to the other 2 membranes. At 24 hours, the difference in the proportion of bacteria-positive fields was statistically significant (P = 0.002, ANOVA); a lesser amount of bacterial plaque was present on the polylactic acid membrane compared to the ePTFE and polyglactin 910 membranes. No difference in the proportion of rod/bacteria-positive fields was demonstrated among the 3 membranes at either 4 or 24 hours. It was concluded that quantitative differences in early plaque accumulation on various membranes seem to be related to the textural and structural characteristics of the surface, which is not adequately represented by the surface Ra value measured with a profilometric instrument.

Absorbable Implants↗
PubMed1998

Mucogingival versus guided tissue regeneration procedures in the treatment of deep recession type defects.

The objective of the study was to compare the clinical efficacy of 3 surgical approaches in the treatment of deep recession type defects. Fifty-four (54) gingival recessions > or = 5 mm were randomly assigned to 1 of the 3 treatment groups by blocking the prognostic variables. The first group was treated with a guided tissue regeneration (GTR) procedure using a bioabsorbable membrane, the second with non-resorbable membrane, and the third with a mucogingival surgical approach consisting of a connective tissue graft combined with a coronally advanced flap (bilaminar technique). No differences, in terms of baseline oral hygiene and defect characteristics, were observed among the 3 groups showing an effective blocking approach. The 1-year results indicated that 1) all treatment approaches resulted in clinically significant root coverage and attachment gain; 2) a statistically significant treatment effect (P = 0.012, ANOVA) was observed comparing the bioabsorbable (4.9+/-0.3 mm), the non-resorbable (4.5+/-0.8 mm), and the bilaminar (5.3+/-0.7 mm) groups, in terms of root coverage; 3) the difference in terms of root coverage between the bilaminar and the non-resorbable membrane groups was statistically significant while differences between the 2 GTR groups or between the bilaminar and the bioabsorbable membrane groups did not reach statistical value; 4) the 95% confidence intervals for the proportions of complete successes showed a similar pattern; 5) no statistical difference was demonstrated in the amount of attachment gain among the 3 groups (P=0.73, ANOVA). A regression model showed that the amount of root coverage was significantly affected by the initial recession depth, the procedure and smoking habits: a poorer root coverage result is expected in case of shallow recession type defects, when either bioabsorbable (P < 0.05) or non-resorbable (P < 0.001) membranes are used instead of a bilaminar technique and if the patient smokes (P < 0.01). It was concluded that the mucogingival bilaminar technique is at least as effective as GTR procedures in the treatment of gingival recession > or = 4 mm and thus recession depth is not the parameter which influences the selection of the surgical procedure.

Absorption↗
PubMed1998

A protocol for maintaining or increasing the width of masticatory mucosa around submerged implants: a 1-year prospective study on 53 patients.

Masticatory mucosa around implants may be useful to enhance esthetics and/or plaque control. This study proposes simplified guidelines for maintaining or obtaining a minimal amount of masticatory mucosa around submerged implants in cases of partial edentulism, and for keeping the need for additional surgery to a minimum. Free gingival grafts were used in the mandibular arch when the width of buccal masticatory mucosa was less than 2 mm. The width of masticatory mucosa expected to be available for attachment to the bone surface buccal to implants was estimated by measuring the distance between the emergence of the implant from bone and the mucogingival junction. When this distance was 3 mm or less, the use of an apically positioned flap for implant exposure was preferred over gingivectomy. The amount of masticatory mucosa buccal to implants was measured 2 weeks, 6 months, and 12 months after implant exposure. In no case was the width of masticatory mucosa less than 2 mm at 1 year. Therefore, this protocol is recommended for the treatment of cases where the presence of an adequate amount of masticatory mucosa is necessary to ensure a satisfying appearance or is useful for facilitating oral hygiene.

Adult↗
PubMed1997

Integrated connective tissue in bioabsorbable barrier material and periodontal regeneration.

The objective of this study was to evaluate the relationship between integrated connective tissue (ICT), that is, the presence of connective tissue into the membrane structure, and the clinical outcome of membrane-supported periodontal surgery. Twenty-six systemically healthy subjects affected by chronic adult periodontitis were enrolled in the study. One tooth site per patient, associated with an angular bony defect and an attachment loss of > 7 mm, was selected to be treated by means of a guided tissue regeneration procedure using a bioabsorbable membrane. Barrier material was surgically removed after 4 weeks for SEM analysis. For each treated site, the difference in clinical attachment loss, probing depth, and gingival recession between the baseline examination and follow-up 6 months after the second surgery was calculated. Gain of attachment was statistically (P < 0.001) greater in sites with no membrane exposure when compared to sites with exposed barrier material (5.5 +/- 1.0 vs. 4.0 +/- 0.6), while further gingival recession was greater (3.0 +/- 0.9 vs. 2.1 +/- 0.5) in sites with clinically exposed membranes. The results of SEM analysis revealed that when connective tissue structures were observed on membrane surfaces, no bacteria could be detected; conversely, areas heavily colonized by bacteria did not show the presence of connective tissue. Regression analysis indicated that integrated connective tissue on the external layer of the barrier material was positively correlated with the amount of attachment gain and negatively with the amount of gingival recession. Bacterial colonization of the membrane was negatively correlated with attachment gain and positively with gingival recession. It was concluded that connective tissue integration is an important biological phenomenon in preventing membrane exposure and bacterial plaque colonization and thus in enhancing the clinical outcome following guided tissue regeneration surgery.

Absorption↗
PubMed1996

Bacterial colonization of barrier material and periodontal regeneration.

The objective of this study was to evaluate the relationship between the presence of bacteria on the tooth-facing surface of ePTFE barriers and the clinical outcome of membrane supported reconstructive periodontal surgery. 20 systemically healthy subjects affected by chronic periodontitis were enrolled. One tooth site per patient, associated with an angular bony defect and a probing attachment loss of > 4 mm, was selected to be treated by means of a guided tissue regeneration procedure using an ePTFE barrier membrane. Antibiotics (Augmentin 1 g/day) for 2 weeks were prescribed. In addition to the use of chlorhexidine for post-surgical plaque control, all patients were recalled once a week for professional tooth cleaning. The barrier material was harvested for SEM analysis after 4-6 weeks. Professional tooth cleaning and reinforcement of sel-performed oral hygiene measures were given at 1 mouth intervals after membrane removal. For each treated site, the difference in probing attachment loss between baseline examination and a follow-up examination after 6 months of healing was calculated. The results of the SEM-analysis revealed that bacterial colonization was evident in the collar area of all the retrieved membranes. In the mid part of the membranes 30 out of 60 microscopic fields (50%) demonstrated microbial colonization, and in the most apical part 9 out of 60 fields (15%). Regression analysis indicated that gain in probing attachment level was positively correlated to initial attachement loss and negatively correlated to microbial colonization of the mid part of the membranes. It was concluded that bacterial colonization in the mid part of the ePTFE membrane reduced the potential gain in probing attachment following GTR-therapy with almost 50%.

Adult↗
PubMed1996

Bacterial colonization of bioabsorbable barrier material and periodontal regeneration.

The objective of the study was to evaluate bacterial colonization of the tooth-facing surface of bioabsorbable membranes and to determine its effect on the clinical outcome of membrane supported reconstructive periodontal surgery. Twenty systemically healthy subjects affected by chronic adult periodontitis were enrolled in the study. One non-furcation tooth site per patient, associated with an angular bony defect and a probing attachment loss of > 5 mm, was selected to be treated by means of a guided tissue regeneration procedure using a polyglicolactic membrane. Antibiotics (amoxicillin/clavulanate potassium 1 g per day) for 2 weeks were prescribed, in addition to the use of chlorhexidine for post-surgical plaque control. All patients were recalled once a week for 5 weeks for professional tooth cleaning. At 5 weeks sites with clinically exposed membranes underwent a second surgery to harvest residual barrier material which was analyzed by scanning electronic microscopic (SEM) for bacterial colonization. Sites with no membrane exposure at 5 weeks were allowed to heal without any other surgical intervention. Professional tooth cleaning and reinforcement of self-performed oral hygiene measures were given at 1 month intervals for the duration of the study. For each treated site the difference in probing attachment loss between baseline examination and a follow-up examination made 6 months after the second surgery was calculated. Gain of probing attachment was statistically (P < 0.001) greater in sites with no membrane exposure when compared to sites with partially exposed barrier material (4.2 +/- 0.5 vs. 3.3 +/- 0.6). The results of SEM analysis revealed that bacterial colonization was evident in all the microscopic fields of the exposed areas of the membranes. In the mid-part of the membranes 16 out of 39 microscopic fields (41%) demonstrated microbial colonization, while no bacteria-positive field was observed in the most apical portion of the membranes. Regression analysis indicated that gain in probing attachment level was negatively correlated to microbial colonization of the mid-part of the membranes. It was suggested the midportion of the tooth-facing surface of polyglicolactic membrane is a critical area for the healing process since its bacterial colonization was detrimental to the outcome of the GTR surgery.

Adult↗
PubMed1996

Guided tissue regeneration versus mucogingival surgery in the treatment of human buccal recessions. A 4-year follow-up study.

The 4-year follow-up results of a clinical trial are reported. The clinical results of the treatment of buccal recession were analyzed comparing the outcomes of a guided tissue regeneration (GTR) procedure with nonresorbable membranes and a 2-step mucogingival procedure consisting of a coronally-positioned free gingival graft in two groups of 25 patients each. The final root coverage was 73.07% in the test group (GTR) and 72.3% in the control group (mucogingival surgery). In the test group, statistically significant recession reduction, probing depth reduction, clinical attachment level gain, and increase of keratinized tissue width were observed. In the control group the results were similar except for probing depth, which did not vary significantly. At the end of the 4-year follow-up period, the average periodontal conditions did not differ between the 2 groups, with the exception of the keratinized tissue width. This was obviously greater in the control group, where a free gingival graft had been carried out. Recessions > or = 5 mm had a greater root coverage after GTR treatment. In both groups, the periodontal parameters remained stable between 18 months and 4 years after surgery, indicating remarkable stability; the only exception was a significant increase in the keratinized tissue width in the test group. When the changes between the baseline and the 4-year follow-up were compared, the average reduction in the recession was similar in the two groups while probing depth reduction and clinical attachment level were greater in the GTR group.

Adolescent↗
PubMed1995

Resorbable membrane in the treatment of human buccal recession: a nine-case report.

Recent studies have reported the successful use of guided tissue regeneration procedures with nonresorbable barrier membranes to treat buccal recession in humans. Nonresorbable membranes, however, require a reentry procedure for removal, disturbing the delicate healing process. Resorbable membranes were used in a guided tissue regeneration procedure in nine patients with one site of buccal recession each. The resorbable barrier yielded satisfactory clinical results, providing significant gains in probing attachment and root coverage. However, both the surgical technique and the design of the barrier used require improvement for application at sites of buccal recession.

Adult↗
PubMed1994

Thermal distortion of different materials in crown construction.

This study compared the thermal distortion of all-ceramic crowns with porcelain-fused-to-metal crowns. The materials exhibited different responses: metal ceramic crowns stabilized after an initial loss of marginal precision, and the all-ceramic crowns continued to distort with each firing cycle.

Aluminum Oxide↗
PubMed1994

Tunnel traction of infraosseous impacted maxillary canines. A three-year periodontal follow-up.

A surgical orthodontic procedure was used to treat deep infraosseous impacted canines (test teeth) associated with the persistence of the deciduous tooth in 15 patients who had the contralateral canine normally erupted (control teeth). The periodontal outcome was evaluated at the end of the orthodontic treatment and 3 years later. After extraction of the deciduous canine, a mucoperiosteal flap was raised on the buccal (seven cases) or palatal (eight cases) aspect, to expose the cusp of the impacted tooth. The empty socket of the deciduous tooth was extended to reach the impacted cusp and to form an osseous tunnel. A chain was passed through the tunnel and fixed to a bonded device on the impacted cusp. The flap was sutured back into its original position. The chain was used for traction to the impacted canine toward the center of the alveolar ridge. No attachment loss and no recession were observed at the end of the active therapy or 3 years later. No significant differences in keratinized tissue width were observed between test and control teeth at the follow-up examination.

Adolescent↗
PubMed1994

Effect of incision and flap reflection on postoperative pain after the removal of partially impacted mandibular third molars.

A clinical trial was carried out to evaluate the influence of incision and reflection of a flap on pain after the removal of partially erupted mandibular third molars. A sequential design for intraindividual comparisons was chosen. The patients underwent bilateral extraction of partially impacted mandibular third molars with a standard incision on one side (control) and without incision (test) on the other side. One week postoperatively, the patients were asked on which side they had experienced more postoperative pain. The preset level of significance (P < .05) was reached after 11 patients were treated. Eight patients had more severe pain on the control side, while three patients did not experience any difference in pain between the two sides. The nonsurgical approach did not increase the chair time and appeared to be an effective way of reducing postoperative discomfort after extraction of partially erupted third molars.

Adolescent↗
PubMed1993

Histologic assessment of new attachment following the treatment of a human buccal recession by means of a guided tissue regeneration procedure.

A deep, long-standing recession on a mandibular incisor was treated in a 56-year-old female patient. The tooth was tilted buccally and was scheduled for extraction. The recession was 8 mm deep, with a pocket depth of 1 mm and no keratinized tissue. The recession was treated by guided tissue regeneration; the membrane was left in place for 4 weeks. The tooth was extracted along with marginal tissues 5 months after the removal of the membrane. At the time of extraction, 4 mm of root coverage had been achieved and 3 mm of keratinized tissue were measured buccally. Histologic measurements showed that 3.66 mm of new connective tissue attachment had been obtained associated with newly formed cementum (2.48 mm) and bone growth (1.84 mm). The crestal bone level after treatment was located coronal to the preoperative location of the gingival margin.

Alveolar Process↗