Morphometric study of the root anatomy in furcation area of mandibular first molars

Furcation involvement in periodontal disease has been a challenge for the dentist. Objective: The aim of this study was to investigate root dimensions in the furcation area of 233 mandibular first molars. Material and Methods: Digital photomicrographs were used to obtain the following measurements on the buccal and lingual surfaces of each tooth: root trunk height (RT), horizontal interadicular distance obtained 1 mm (D1) and 2 mm (D2) below the fornix and interadicular angle (IA). Results: Mean standard deviation of buccal and lingual furcation measurements were, respectively, 1.37 +/- 0.78 mm and 2.04 +/- 0.89 mm for RT; 0.86 +/- 0.39 mm and 0.71 +/- 0.42 mm for D1; 1.50 +/- 0.48 mm and 1.38 +/- 0.48 mm for D2; 41.68 +/- 13.20 degrees and 37.78 +/- 13.18 degrees for IA. Statistically significant differences were found between all measured parameters for buccal and lingual sides (p<0.05, paired t test). Conclusions: In conclusion, the lingual furcation of mandibular first molars presented narrower entrance and longer root trunk than the buccal furcation, suggesting more limitation for instrumentation and worse prognosis to lingual furcation involvements in comparison to buccal lesions.

Intrusion of teeth with class III furcation: a clinical, histologic and histometric study in dogs

Aim: To assess orthodontic intrusion effects on periodontal tissues in dogs' pre-molars with class III furcations treated with open flap debridement (OFD) or with guided tissue regeneration (GTR) associated to bone autograft (BA).Material and Methods: Class III furcations were created in the pre-molars of seven mongrel dogs. After 75 days, teeth were randomly treated with OFD or GTR/BA. After 1 month, metallic crowns were assembled on pre-molars and connected apically to mini-implants by nickel-titanium springs. Teeth were randomly assigned to orthodontic intrusion (OFD+I and GTR/BA+I) groups or no movement (OFD and GTR/BA) groups. Dogs were sacrificed after 3 months of movement and 1 month retention.Results: All class III furcations were closed or reduced to class II or I in the intrusion groups, while 50% of the lesions in non-moved teeth remained unchanged. Intruded teeth presented higher probing depth and lower gingival marginal level than non-moved teeth (p < 0.01). Clinical attachment gain was reduced in the intrusion groups by the end of retention (p < 0.05). OFD+I presented smaller soft tissue area and larger bone tissue area than other groups (p < 0.05).Conclusion: Orthodontic intrusion with anchorage via mini-implants improved the healing of class III furcation defects after OFD in dogs. GTR/BA impaired those results.

Detection of periapical lesion development by conventional radiography or computed tomography

Objective. The aim of this study was to detect the development of experimentally induced periapical lesions using conventional radiography and computed tomography.Study design. The root canals of dogs' teeth were exposed to the oral environment for 7 days for contamination and then sealed for 7 days (GI), 15 days (GII), 30 days (GIII), and 60 days (GIV). Immediately after each experimental period, radiographs and tomograms were taken in order to detect the occurrence of periapical bone resorption. The periapical radiographs were digitized and areas of bone resorption were measured using the VIXWIN 2000 software. Scores were assigned to the tomograms based on the progression of periapical bone resorption. The specimens were evaluated by calibrated examiners who were blinded to the groups. The radiographic results were analyzed by ANOVA and Tukey's test (P <.05) and the tomographic results were analyzed by Kruskal-Wallis and Dunn's tests (P <.05).Results. The radiographic evaluation did not reveal periapical lesions at the 7-day control. Lesions were radiographically visible at 15 and 30 days (47.4% and 77.8% of the cases, respectively) and presented similar dimensions (P <.05). At 60 days, lesions were detected in all specimens, presenting larger dimensions than those of the earlier evaluation periods (P <.05). The tomographic evaluation detected lesions at 7 and 15 days (32.5% and 83.3% of the cases, respectively). Lesions were detected in all specimens at the 30- and 60-day periods, when the greatest values of bone resorption were observed (P <.05).Conclusions. Tomography was able to detect periapical lesion development in its initial stages, even when the lesions were undetectable radiographically.

Comparative radiographic and histological analyses of periapical lesion development

Objective. The present study evaluated the dynamics of the development of periapical lesions.Study design. Root canals from dogs' teeth were exposed to the oral environment, and then sealed for 7 days (Group A), 15 days (Group B), 30 days (Group C), and 60 days (Group D). After each experimental period, radiographs were taken to detect periapical bone resorption. In addition, histological sections from the periapical region were prepared. The radiographic and histological results were analyzed by ANOVA and Tukey's, Wilcoxon, and Pearson's tests. Significance level was set at 5%.Results. Lesions were radiographically visible at 15 and 30 days, and had similar size at these periods (P > .05). At 60 days, lesions were larger than in the other periods (P < .05). Bone resorption was detected histologically at 7 days. The greatest values of bone resorption were observed at the 30- and 60-day periods (P < .05). The results of the methods of evaluation were similar only at the 30-day period. There was no correlation between the radiographic and histological results.Conclusions. Periapical radiography did not provide detection of periapical lesion in its initial stages. The periapical lesions became more evident radiographically when the bone resorption area increased. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009;107:442-447)

Effects of AV3V lesion on pilocarpine-induced pressor response and salivary gland vasodilation

The cholinergic agonist pilocarpine injected intraperitoneally (ip) increases mean arterial pressure (MAP) and superior mesenteric (SM) vascular resistance and reduces submandibular/sublingual gland (SSG) vascular resistance. In the present study, we investigated the effects of electrolytic lesions of the anteroventral third ventricle (AV3V) region on the changes in MAP, SM, and SSG vascular resistances induced by ip pilocarpine. Male Holtzman rats anesthetized with urethane (1.0 g/kg) and chloralose (60 mg/kg) were submitted to sham or electrolytic AV3V lesions and bad pulsed Doppler flow probes implanted around the arteries. Contrary to sham rats, in 1-h and 2-day AV3V-lesioned rats, pilocarpine (4 mu mol/kg) ip decreased MAP (-41 +/- 4 and -26 4 mm Hg, respectively, vs. sham: 19 +/- 4 mm Hg) and SM (-48 +/- 11 and -45 +/- 10%, respectively, vs. sham: 41 +/- 10%) and hindlimb vascular resistances (-65 +/- 32 and -113 +/- 29%, respectively, vs. sham: 19 +/- 29%). In 7-day AV3V-lesioned rats, pilocarpine produced no changes on MAP and SM and hindlimb vascular resistances. Similar to sham rats, pilocarpine reduced SSG vascular resistance 1 h after AV3V lesions (-46 +/- 6%, vs. sham: -40 +/- 6%), but it produced no effect 2 days after AV3V lesions and increased SSG vascular resistance (37 6%) in 7-day AV3V-lesioned rats. The responses to ip pilocarpine were similar in 15-day sham and AV3V-lesioned rats. The cholinergic antagonist atropine methyl bromide (10 nmol) iv slightly increased the pressor response to ip pilocarpine in sham rats and abolished for 40 min the fall in MAP induced by ip pilocarpine in 1-h AV3V-lesioned rats. The results suggest that central mechanisms dependent on the AV3V region are involved in the pressor responses to ip pilocarpine. Although it was impaired 2 and 7 days after AV3V lesions, pilocarpine-induced salivary gland vasodilation was not altered 1 h after AV3V lesions which suggests that this vasodilation is not directly dependent on the AV3V region. (c) 2005 Elsevier B.V. All rights reserved.

Effect of electrolytic and chemical lesion by ibotenic acid of the septal area on water and salt intake

Water and sodium chloride intake was studied in male Holtzman rats weighing 250-300 g that had been subjected to electrolytic and chemical lesions of the septal area (SA). Water intake increased in animals with electrolytic lesion of the SA bilaterally from 169.37 +/- 8.55 (sham) to 214.87 +/- 23.10 ml/5 days (lesioned). Water intake decreased after ibotenic acid lesion of the SA from 229.33 +/- 27.60 to 127.33 +/- 22.84 ml/5 days. Sodium chloride intake (1.5%) increased in animals with electrolytic lesion of the SA from 10.0 +/- 1.73 to 15.5 +/- 1.95 ml/5 days after lesion. Also sodium chloride (1.5%) intake increased after ibotenic acid injection into the SA to a greater extent (from 7.83 +/- 1.25 to 14.33 +/- 1.87 ml/5 days). The results indicate that the water intake response may be due to lesions that involve cell bodies and fibers of passage and that the sodium intake response can also be induced by lesions which involve only cell bodies. Finally, these results led us to conclude that the SA uses its cell bodies and afferent bodies and fibers for processing inputs mediating water intake and salt appetite and that the cells bodies of the SA are implicated in increased water intake. (C) 1998 Elsevier B.V.

Histological and histomorphometrical evaluation of furcation perforations filled with MTA, CPM and ZOE

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

The compulsive-like aspect of the head dipping emission in rats with chronic electrolytic lesion in the area of the median raphe nucleus

Head dipping (HD) is a behavioral pattern considered to have a risk assessment or an exploratory role and is used as a complementary parameter to evaluate anxiety in experimental animals. Since rats with electrolytic lesion in the area of the median raphe nucleus displayed high frequencies of HD in a previous study, the present investigation was undertaken to confirm this observation and to determine its anxiety-related origin. HD episodes were counted in adult male Wistar rats (270-350 g) with electrolytic lesion (N = 11) and sham-lesioned controls (N = 12). When HD was measured for 60 min on an elevated open platform, lesioned rats emitted 13 times more HD than controls (264.7 ± 93.3 vs 20.3 ± 7.6 episodes), with the difference being statistically significant (P < 0.05). HD counts during 10-min sessions held 7, 14, 21, 27, and 63 days after lesion showed significantly higher means (range: 28.14 ± 5.38 to 62.85 ± 9.48) compared to sham-lesioned controls (range: 7.37 ± 1.13 to 8.5 ± 1.45). Normal rats stepped down into their home cages when the vertical distance between them and the cage was short (16 cm), and the step-down latencies increased with increasing depths (36.7 ± 7.92 to 185.87 ± 35.44 s). Lesioned rats showed a similar behavior when facing the shortest depth, but had a significantly increased number (23.28 ± 2.35 episodes) and latency (300 ± 0.00 s) of HD compared to normal rats (9.25 ± 1.37 episodes and 185.87 ± 35.44 s) when facing the greatest depth (30 cm). This suggests that HD may be a depth-measuring behavior related to risk assessment.

Experimental paracoccidioidomycosis in hamster: transmission electron microscopy of inoculation site lesion

Estudou-se sequencialmente, à microscopia eletrônica de transmissão, a interação entre Paracoccidioides brasiliensis (Pb) e células inflamatórias em hamsters inoculados por via intratesticular. Seis horas após inoculações havia predominância de neutrófilos, estando presentes algumas células mononucleares e eosinófilos. Os neutrófilos foram progressivamente substituídos por células mononucleares. Fungos viáveis apresentavam-se fagocitados ou circunscritos por células inflamatórias, geralmente com ampla interface hospedeiro-parasita. Fungos mortos ou degenerados eram acompanhados de interfase estreita. A camada externa da parede do Pb era às vezes quebrada quando em contacto com neutrófilos, em vários pontos, sendo os fragmentos dessa parede descamados e fagocitados. Células fúngicas pequenas com um único núcleo se relacionavam com ampla interfase enquanto as células maiores e multinucleadas apresentavam paredes irregulares, por vezes, contendo lomasoma e/ou estrutura semelhante à mielina. Diferentes padrões de interação do Pb com células do hospedeiro podem ser decorrentes do a fluxo de células inflamatórias funcionalmente diferentes ao local de inoculação ou à idade dos fungos ou ambos os fatores.

Anxiolytic-like effects of median raphe nucleus lesion in the elevated T-maze

The cell bodies of 5-HT containing neurons that innervate the limbic forebrain are mainly found in the dorsal raphe nucleus and in the median raphe nucleus (MRN). To assess the role of the median raphe nucleus in anxiety, rats bearing either electrolytic or 5-HT-selective neurotoxic lesion of the MRN were tested in the elevated T-maze. This apparatus consists of two opposed open arms perpendicular to one enclosed arm. Two tasks are performed in succession by the same rat in one experimental session, namely inhibitory avoidance of the open arm, taken as a measure of conditioned anxiety and one-way escape from the open arm, considered as a measure of unconditioned fear. The test was performed 7 days after the electrolytic lesion (3 mA, 10 s) or 14 days after the neurotoxic lesion (5,7-DHT, 8 mug/1 mul). The results showed that while the electrolytic lesion impaired both inhibitory avoidance and one-way escape, the neurotoxic lesion impaired only inhibitory avoidance. Therefore, serotonergic pathways originating in the MRN seem to participate in the modulation of conditioned anxiety but not unconditioned fear. Other neurotransmitter systems that either originate in or pass through the MRN may regulate unconditioned fear. (C) 2003 Elsevier B.V. All rights reserved.

Behavioural and neurochemical effects of phosphatidylserine in MPTP lesion of the substantia nigra of rats

The present study investigated the effects of intranigral MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) infusion on rats treated with phosphatidylserine and evaluated in two memory tasks and on striatal dopamine levels. The results indicated that MPTP produced a significant decrease in the avoidance number in comparison to sham-operated and non-operated rats submitted to a two-way avoidance task. MPTP-lesioned rats exhibited an increase in the latencies to find the platform in cued version of the water maze in comparison to sham-operated and non-operated animals. The tested toxin reduced striatal dopamine levels in comparison to sham-operated and non-operated groups. A final surprising result was that phosphatidylserine was unable to reverse the cognitive deficits produced by MPTP or the reduction of striatal dopamine levels. In conclusion, the data suggest that MPTP is a good model to study the early impairment associated with Parkinson's disease and phosphatidylserine did not improve the memory impairment induced by MPTP. (C) 2003 Elsevier B.V. All rights reserved.