Flap vs. "flapless" surgical approach at immediate implants: a histomorphometric study in dogs

AimTo compare the remodeling of the alveolar process at implants installed immediately into extraction sockets by applying a flap or a "flapless" surgical approach in a dog model.Material and methodsImplants were installed immediately into the distal alveoli of the second mandibular premolars of six Labrador dogs. In one side of the mandible, a full-thickness mucoperiosteal flap was elevated (control site), while contra-laterally, the mucosa was gently dislocated, but not elevated (test site) to disclose the alveolar crest. After 4 months of healing, the animals were sacrificed, ground sections were obtained and a histomorphometric analysis was performed.ResultsAfter 4 months of healing, all implants were integrated (n=6). Both at the test and at the control sites, bone resorption occurred with similar outcomes. The buccal bony crest resorption was 1.7 and 1.5 mm at the control and the test sites, respectively.Conclusions"Flapless" implant placement into extraction sockets did not result in the prevention of alveolar bone resorption and did not affect the dimensional changes of the alveolar process following tooth extraction when compared with the usual placement of implants raising mucoperiosteal flaps.To cite this article:Caneva M, Botticelli D, Salata LA, Souza SLS, Bressan E, Lang NP. Flap vs. "flapless" surgical approach at immediate implants: a histomorphometric study in dogs.Clin. Oral Impl. Res. 21, 2010; 1314-1319.doi: 10.1111/j.1600-0501.2009.01959.x.

Influence of various implant platform configurations on peri-implant tissue dimensions: an experimental study in dog

AimTo evaluate the influence (i) of various implant platform configurations and (ii) of implant surface characteristics on peri-implant tissue dimensions in a dog model.Material and methodsMandibular premolars and first molars were extracted bilaterally in six Labrador dogs. After 3 months of healing, two implants, one with a turned and a second with a moderately rough surface, were installed on each side of the mandible in the premolar region. on the right side of the mandible, implants with a tapered and enlarged platform were used, while standard cylindrical implants were installed in the left side of the mandible. Abutments with the diameter of the cylindrical implants were used resulting in a mismatch of 0.25 mm at the tapered implant sites. The flaps were sutured to allow a non-submerged healing. After 4 months, the animals were sacrificed and ground sections were obtained for histometric assessment.ResultsAll implants were completely osseointegrated. A minimal buccal bone resorption was observed for both implant configurations and surface topographies. Considering the animals as the statistical unit, no significant differences were found at the buccal aspect in relation to bone levels and soft tissue dimensions. The surface topographies did not influence the outcomes either.ConclusionsThe present study failed to show differences in peri-implant tissue dimensions when a mismatch of 0.25 mm from a tapered platform to an abutment was applied. The surface topographies influence a neither marginal bone resorption or peri-implant soft tissue dimension.To cite this article:Baffone GM, Botticelli D, Pantani F, Cardoso LC, Schweikert MT, Lang NP. Influence of various implant platform configurations on peri-implant tissue dimensions: an experimental study in dog.Clin. Oral Impl. Res. 22, 2011; 438-444.

Role of teeth adjacent to implants installed immediately into extraction sockets: an experimental study in the dog

Aim: To evaluate the influence of the presence of both adjacent teeth on the level of alveolar bony crest at sites where implants were installed into the socket immediately after tooth extraction.Material and methods: Six Labrador dogs were used. Extractions of all teeth from the second premolar to the first molar were performed in the right side of the mandible, after full-thickness flap elevation. In the left side of the mandible, an endodontic treatment of the mesial root of the third and fourth premolars was performed. Full-thickness flaps were elevated, the teeth hemisected, and the distal roots removed. Immediately after, implants were bilaterally installed with the margin flush to the buccal bony crest. The implants were placed in the center of the alveolus at the third premolars and toward the lingual bony plate of the alveolus at the fourth premolars. After 3 months of healing, the animals were euthanized.Results: All implants were integrated in mature bone. More bone resorption was observed at the test compared to the control sites. At the buccal aspect, a resorption of 2.8 +/- 0.5 and 1.6 +/- 0.4 mm at the third premolars and of 2.4 +/- 0.6 and 0.8 +/- 0.7 mm at the fourth premolars were found, at the test and control sites, respectively. At the lingual aspect, the bony crest was apically located in relation to the implant shoulder 1.5 +/- 0.3 and 0.5 +/- 0.5 mm at the third premolars and 1.6 +/- 0.6 and 0.3 +/- 1.1 mm at the fourth premolars, at the test and control sites, respectively. A lower buccal bone resorption was found at the control implants placed lingually.Conclusion: Multiple extractions of teeth adjacent to a socket into which implants were installed immediately after, tooth extraction induced more alveolar bone recession compared to sites where the adjacent teeth were preserved. Moreover, an implant placed more lingually yielded less recession of the buccal aspect of the implant.

Healing outcomes at implants installed in grafted sites: an experimental study in dogs

Aim: To evaluate the integration of implants installed using a surgical guide in augmented sites with autologous bone or deproteinized bovine bone mineral (DBBM) blocks, concomitantly with a collagen membrane.Material and methods: Mandibular molars were extracted bilaterally in six Labrador dogs, the buccal bony wall was removed, and a box-shaped defect was created. After 3 months, flaps were elevated, a bony graft was harvested from the ascending ramus, and secured to the lateral wall of the defect by means of screws. In the left mandibular side, a DBBM block was fixed into the defect. A resorbable membrane was applied at both sides, and the flaps were sutured. After 3 months, flaps were elevated, and a customized device was used as surgical guide to prepare the recipient sites in the interface between grafts and parent bone. One implant was installed in each side of the mandible. After 3 months, biopsies were harvested, and ground sections were prepared for histologic evaluation.Results: One autologous bone block graft was lost before implant installation. The width of the alveolar crest at the test sites (DBBM) was 5.4 +/- 1.2 mm before, 9.4 +/- 1.2 mm immediately after grafting, and 9.3 +/- 1 mm at implant installation. At the control sites (autologous bone), the corresponding values were: 5.2 +/- 1, 9 +/- 1.2, and 8.7 +/- 0.9 mm, respectively. All implants installed were available for histologic evaluation (n = 5). The autologous bone grafts, rich in vessels and cells, were integrated in the parent bone, and only little non-vital bone was found. The BIC% was 56.7 +/- 15.6% and 54.2 +/- 13.2% at the buccal and lingual aspects, respectively. At the test sites, the DBBM appeared to be embedded into connective tissue, and very little newly formed bone was encountered within the grafts. The BIC% was 5.8 +/- 12.3% and 51.3 +/- 14.2% at the buccal and lingual aspects, respectively.Conclusions: Autologous bone blocks used to augment the alveolar bony crest horizontally allowed the complete osseointegration of implants installed after 3 months of healing. However, similar blocks of DBBM did not promote osseointegration, although the installed implants were stable owing to the osseointegration in the sites of the parent bone.

Morphological changes in the cephalic salivary glands of females and males of Apis mellifera and Scaptotrigona postica (Hymenoptera, Apidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Taxonomic comments and an identification key to species for the Smooth-hound sharks genus Mustelus Link, 1790 (Chondrichthyes: Triakidae) from the Western South Atlantic.

Five species of smooth-hound sharks genus Mustelus (Family Triakidae) are know in the western South Atlantic, as follows: Mustelus canis (Mitchell 1815); Mustelus fasciatus (Garman 1913); Mustelus higmani Springer & Lowe 1963; Mustelus norrisi Springer 1939; and Mustelus schmitti Springer 1939. In the present paper, new data on the anatomy, morphometrics and meristic characters are given. Taxonomic aspects and comparison between the species are discussed. Most general body morphologic measurements and proportions are useless as a tool for species identification, since many of them show remarkable intraspecific variations. Head proportions and structures related seem to be a more adequate procedure to identify the species of Mustelus. The labial folds proportions, internasal distance and orbit diameter were the most useful character to separate the western South Atlantic species. The buccopharingeal pattern of denticles as well as tooth counts not was useful to distinguish the Mustelus species from western South Atlantic adequately, due great intraspecific variation.

Treatment of gingival recession: Comparative study between subepithelial connective tissue graft and guided tissue regeneration

Background: Various procedures have been proposed to treat gingival recession, but few studies compare these procedures to each other. The purpose of this study was to evaluate a clinical comparison of subepithelial connective tissue graft (SCTG) and guided tissue regeneration (GTR) with a collagen membrane in the treatment of gingival recessions in humans. Methods: Twenty-four defects were treated in 12 patients who presented canine or pre-molar Miller Class I and/or II bilateral gingival recessions. Both treatments were performed in all patients, and clinical measurements were obtained at baseline and 18 months after surgery. These clinical measurements included gingival recession height (GR), root coverage (RC), probing depth (PD), keratinized tissue width (KT), and final esthetic result. Results: Both SCTG and GTR with a bioabsorbable membrane and bone graft demonstrated significant clinical and esthetic improvement for gingival recession coverage. The SCTG group was statistically significantly better than GTR for height of GR (SCTG = 0.2 mm, GTR = 1.12 mm, P = 0.02) and KT (SCTG = 4.58 mm, GTR = 2.5 mm, P <0.0001). However, PD was statistically significantly better for GTR than SCTG treatment (GTR = 1.66 mm, SCTG = 1.00, P = 0.01). The 2 procedures were statistically similar in root coverage (SCTG = 95.6%, GTR = 84.2%, P = 0.073). The esthetic condition after both treatments was satisfactory (P = 0.024). Conclusions: It was concluded that the gingival recessions treated with the SCTG group were superior for GR, RC, and KT clinical parameters, while GTR demonstrated better PD reduction. The final esthetic results were similar using both techniques.

Effect of whitening agents on dentin bonding

Background: Several studies have shown a reduction in enamel bond strengths when the bonding procedure is carried out immediately after vital bleaching with peroxides. This reduction in bond strengths has become a concern in cosmetic dentistry with the introduction of new in-office and waiting-room bleaching techniques. The aim of this in vitro study was to evaluate the effect of three bleaching regimens: 35% hydrogen peroxide (HP), 35% carbamide peroxide (CP), and 10% CP, on dentin bond strengths. Materials and Methods: One hundred and twenty fresh bovine incisors were used in this study. The labial surface of each tooth was ground flat to expose dentin and was subsequently polished with 600-grit wet silicon carbide paper. The remaining dentin thickness was monitored and kept at an average of 2 mm. The teeth were randomly assigned to four bleaching regimens (n = 30): (A) control, no bleaching treatment; (B) 35% HP for 30 minutes; (C) 35% CP for 30 minutes; and (D) 10% CP for 6 hours. For each group, half of the specimens (n = 15) were bonded with Single Bond/Z100 immediately after the bleaching treatment, whereas the other half was bonded after the specimens were stored for 1 week in artificial saliva at 37°C. The specimens were fractured in shear using an Instron machine. Results: For the groups bonded immediately after bleaching, one-way analysis of variance (ANOVA) followed by the Duncan's post hoc test revealed a statistically significant reduction in bond strengths in a range from 71% to 76%. For the groups bonded at 1 week, one-way ANOVA showed that group B (35% HP for 30 min) resulted in the highest bond strengths, whereas 10% CP resulted in the lowest bond strengths. Student's t-test showed that delayed bonding resulted in a significant increase in bond strengths for groups B (35% HP) and C (35% CP); whereas the group bleached with 10% CP (group D) remained in the same range obtained for immediate bonding. Storage in artificial saliva also affected the control group, reducing its bond strengths to 53% of the original. ©2000 BC Decker Inc.

Enzymes present in the thoracic gland extracts from workers and males of Apis mellifera (Hymenoptera: Apidae)

This research deals with the analysis of the enzymes present in thoracic gland extracts from newly emerged, nurse workers, forager workers, newly emerged males, and mature males of A. mellifera L. (Hymenoptera, Apoidea, Apidae). The enzymes found in larger quantities in the thoracic gland occurred in all classes of workers and are digestive. Acid phosphatase and Naphtol-AS-BI-phosphohydrolase act in protein synthesis, leucine arylamidase hydrolyses proteins and a-glucosidase actuate in the nectar processing into honey. Naphtol-AS-BI-phosphohydrolase was found in larger quantities only in workers, this suggests action in protein synthesis by the thoracic gland, b-galactosidase is in larger amounts in the newly emerged bees (workers and males) this aids in the provision of other substances to be used as an energy source when glucose or sucrose are absent. Differences between enzymatic profiles from workers and males are usually related to their colony tasks, or related to their physiological necessities per individual in specific life stages.

P-077. Myxoma of bone. Review of 17 cases

Myxoma of bone (fibromyxoma) is a slowly growing, locally invasive tumor that almost always occurs in the facial bones. The tumor has a potential to recur, but does not metastasize. The lesion is usually painless but causes slowly progressive swelling, sometimes resulting in severe facial deformity. Aim: Review of myxoma of bone experience in two institutions. Methods: Retrospective chart review of all patients with diagnose of myxoma/fibromyxoma of bone identified in the tumor registry of two referral cancer centers: Hospital Erasto Gaerntner (HEG), Curitiba, PR Brazil and University of Sao Paulo (UNESP), Aracaatuba Campus, Sao Paulo, SP Brazil. We reviewed the age, sex, ace, presenting symptoms, topography of lesion and treatment. Results: From January 1972 to July 2000 we found 17 patients from both institutions that met the diagnostic criteria; 15 from HEG and two from UNESP. The median age was 32 years (range 10-55 years). Eleven patients were male, 14 were white and three were black. Only three patients presented with local pain, the remaining were free of symptoms, presenting only with local tumor. The tumor affected the maxilla in 11 patients (six on the right), the mandible in five and the zygomatic bone in one. All patients were treated by excisional surgery and one patient received adjuvant radiation therapy. Nine patients needed reconstruction after the tumor excision. Five of them were reconstructed with local soft tissue flaps; two received iliac crest autologous bone graft; and two had a microvascularized autologous fibula graft. Conclusion: The myxoma of bone in our experience is a rare tumor and occurs more frequently in the maxilly bone in young males. These findings are consistent with the literature data.

Treatment Effects Produced by Fränkel Appliance in Patients with Class II, Division 1 Malocclusion

The purpose of this investigation was to evaluate the dentoalveolar and skeletal cephalometric changes produced by the Fränkel appliance in individuals with a Class II, division 1 malocclusion. Lateral cephalograms of 44 patients of both sexes were divided in two groups of 22 each. The control group was comprised of untreated Class II children with an initial mean age of eight years and seven months who were followed without treatment for a period of 13 months. The Fränkel group had an initial mean age of nine years and was treated for a mean period of 17 months. Lateral cephalometric headfilms of each patient were obtained at the beginning and end of treatment. The Fränkel appliance produced no significant changes in maxillary growth during the evaluation period, while a statistically significant increase in mandibular length was observed. The maxillomandibular relationship improved mostly because of an increase in mandibular length. In addition, there were no statistically significant differences in the craniofacial growth direction between the Fränkel and the control group, both showing a slight downward rotation of the palatal plane. The Fränkel appliance produced a labial tipping of the lower incisors and a lingual inclination of the upper incisors as well as a significant increase in mandibular posterior dentoalveolar height. It was concluded that the main effects of the Fränkel appliance during this time period were mostly dentoalveolar with a smaller but significant skeletal mandibular effect.

Lethal photosensitization in microbiological treatment of ligature-induced peri-implantitis: a preliminary study in dogs

This pilot study evaluated, by culture testing, the effectiveness of lethal photosensitization for the microbiological treatment of peri-implantitis in dogs. Experimental peri-implantitis was induced by ligature placement for 2 months. Following ligature removal, plaque control was instituted by scrubbing with 0.12% chlorhexidine daily for 12 months. Subsequently, mucoperiosteal flaps were elevated for scaling the implant surface. Microbial samples were obtained with paper points before and after treatment of implant surfaces by means of 100 microg/ml toluidine blue O (TBO,) and were exposed, for 80 s, to light with a wavelength of 685 nm from a 50 mW GaAlAs diode laser. The mean initial and final bacterial counts were 7.22 +/- 0.20 and 6.84 +/- 0.44 CFU/ml, respectively for TVC (P < 0.0001); 6.19 +/- 0.45 and 3.14 +/- 3.29 CFU/ml for P. intermedia/nigrescens (P = 0.001); 5.98 +/- 0.38 and 1.69 +/- 2.90 CFU/ml for Fusobacterium spp. (P = 0.001); and 6.07 +/- 0.22 to 1.69 +/- 2.94 CFU/ml for beta-hemolytic Streptococcus (P = 0.0039). It may be concluded that lethal photosensitization resulted in a reduction of the bacterial count. Complete elimination of bacteria was achieved in some samples.

Comparative study of MTA and other materials in retrofilling of pulpless dogs' teeth

This in vivo study compared the effect of mineral trioxide aggregate (MTA), IRM, Super EBA and ZOE in a puttylike consistency, used as retrofilling materials, in the healing process of periapical tissue of pulpless dogs' teeth submitted to a conventional retrofilling technique. Twenty-four premolars obtained from three dogs were used. At the first intervention, the animals were anesthetized, coronal access was obtained and pulpectomy was done. Root canals were kept open to the oral environment for 180 days to induce the formation of apical lesions. After surgical removal of the lesions with curettes, 2 mm of the apical root was cut out perpendicular to the long axis of the teeth, and root-end cavities were shaped with a low-speed round bur. The bone cavities were irrigated and dried, and the root-end cavities were filled with MTA, IRM, Super EBA and ZOE in a puttylike consistency. The bone cavities were passively filled with blood and flaps were sutured. The coronal access openings were cleaned and double-sealed with ZOE and amalgam. After 180 days, the animals were killed by anesthetic overdose, maxilla and mandible were removed and the pieces were processed for histomorphologic analysis. Data were evaluated blindly on the basis of several histopathologic events and the scores obtained were analyzed statistically using the Kruskal Wallis test. No significant differences were observed among MTA, Super EBA and IRM (p>0.05). However, ZOE had a significantly more negative influence on the apical healing (p<0.05). In conclusion, MTA, Super EBA and IRM had similar histopathologic effects among each other and better performance than ZOE used in a puttylike consistency. Furthermore, only MTA stimulated hard tissue deposition in direct contact with the retrofilling material, even when it was inserted under critical conditions.

Treatment of developmental defect of upper lip with carbon dioxide laser radiation (CO2): First surgical time

With the exception of the cleft lip, developmental defects (DD) of the lip are rare. The upper lip originates from the ectomesenchyme and is formed by the merging of the nasal medial and lateral processes with the maxillary process. Disturbances during this formation period can cause DD with functional and/or esthetic repercussions. We present a case of DD of the upper lip in a patient with a history of progressive growth of the left lateral portion of the upper lip that occurred from the time of birth until the age of 22 years. Clinical examination revealed hypertrophy of the area from the left philtral columns to the left commissure of the lip, extending the portion of the surface mucosa creating a flaccid and asymptomatic tissue mass. All other buccal structures appeared to be within normal limits and without any evidence of defects or deformities. In the surgical planning we decided to carry out corrective surgery in two phases. The first phase accomplished a conservative excision of the total abnormal labial tissue mass with a CO2 laser radiation (5 W in continuous mode, bunch diameter φ = 0.6 mm with a power density of 768 W/cm2 and fluency of 0.231 J/cm2) being careful to preserve the vermilion portion of the lip. Postsurgical clinical evaluations were done every three days until the skin sutures were removed and then every seven days until two months post surgery. While the entire mass of excessive tissue could not be completely removed, the removal of the excessive mucosal tissue produced a very good outcome relative to lip function, with a good esthetic result without scarring, and good tissue mobility. The results showed that the CO2 laser is an extremely useful instrument that can provide excellent control of the surgical field and allow for healing that produces excellent functional and esthetic results. © 2005 Taylor & Francis.

Lower intercanine width and gingival margin changes. A retrospective study.

OBJECTIVE: To determine if changes in the lower intercanine widths during orthodontic treatment with fixed appliances result in gingival margin changes around the lower canines and incisors. METHOD: Pre- and post-treatment intra-oral photographs and orthodontic study models of 178 Caucasian adolescents (101 female, 77 male) were used. All subjects were treated with fixed appliances. The subjects had mean ages of 11.41 (SD: 1.83) years and 14.91 (SD: 1.78) years on their initial and final records respectively. The latter were taken 28 days or more after the appliances had been removed. The inclusion criteria were: Angle Class I or Class II malocclusion (with or without transverse and/or vertical discrepancies); nonextraction treatment; less than 4 mm crowding or spacing; fully erupted lower incisors and good periodontal health. The intercanine widths and the positions of the gingival margins relative to the maximum curvatures of the labial surfaces of the lower canines and incisors were measured with digital calipers. RESULTS: A significant association was found between unaltered intercanine widths and coronal migration of the gingival margins (p = 0.045). There were no significant associations between either increased or reduced intercanine widths and changes in the gingival margins. CONCLUSIONS: Following orthodontic treatment coronal migration of the gingival margins around the lower incisors and canines is more likely to be associated with an unaltered intercanine width.