Clinical and radiographic changes around dental implants inserted in different levels in relation to the crestal bone, under different restoration protocols, in the dog model

Background: The aim of the present study was to evaluate clinical and radiographic changes that occur around dental implants inserted in different levels in relation to crestal bone under different restoration protocols.Methods: Thirty-six implants were inserted in the edentulous mandible of six mongrel dogs. Each implant was assigned to an experimental group according to the distance from the top of the implant to the crestal bone: Bone Level (at crestal bone level), Minus 1 (1 mm below crestal bone), or Minus 2 (2 mm below crestal bone). Each hemimandible was submitted to a restoration protocol: conventional (prosthesis was installed 120 days after implant placement, including 30 days with healing cap) or immediate (prosthesis was installed 24 hours after implant placement). Fixed partial prostheses were installed bilaterally in the same day. After 90 days, clinical and radiographic parameters were evaluated.Results: As long as the implants were inserted in more apical positions, the first bone-to-implant contact (fBIC) was positioned more apically (P<0.05). However, the apical positioning of the implants did not influence the ridge loss or the position of the soft tissue margin (PSTM) (P>0.05). In addition, in immediately restored sites, the PSTM was located significantly more coronally than that in conventionally restored sites (P=0.02).Conclusions: Despite the more apical positioning of the fBIC, the height of the peri-implant soft tissues and ridge was not jeopardized. Moreover, the immediate restoration protocol was beneficial to the maintenance of the PSTM. Further studies are suggested to evaluate the significance of these results in longer healing periods.

Homeopathic Symphytum officinale increases removal torque and radiographic bone density around titanium implants in rats

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

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.

The use of bone scintigraphy to detect active Hansen's disease in mutilated patients

Mutilation of extremities was very frequent in patients affected by leprosy in the past; although it is now much less common, it is still seen, mainly in patients with long-term disease. In general, mutilation of the nose and ears is caused by the bacillus and mutilation of the hands and feet a consequence of chronic trauma. Leprosy must be chronically treated and any decision to interrupt therapy is based on laboratory tests and biopsy. Scintigraphy is a non-invasive procedure which could be of great value in to determining disease activity. We studied eight patients (five males and three females, aged 64-73 years) who presented with mutilation of the nose (2), ear (1), feet (3) or foot and hand (2), Conventional three-phase bone scintigraphy (750 MBq) and X-ray examinations of the affected areas were performed in all patients. Bone scintigraphy was abnormal in four patients (the presence of bacilli was confirmed by biopsy in two of them), and normal in the other four. In all patients except for the one with ear mutilation, radiography only showed the absence of bone. We conclude that bone scintigraphy is very useful to determine disease activity in cases of mutilation caused by leprosy. It seems to be superior to conventional radiography and may enable bone biopsies to be avoided.

Comparison of simulated periodontal bone defect depth measured in digital radiographs in dedicated and non-dedicated software systems

Objectives: To compare simulated periodontal bone defect depth measured in digital radiographs with dedicated and non-dedicated software systems and to compare the depth measurements from each program with the measurements in dry mandibles.Methods: Forty periodontal bone defects were created at the proximal area of the first premolar in dry pig mandibles. Measurements of the defects were performed with a periodontal probe in the dry mandible. Periapical digital radiographs of the defects were recorded using the Schick sensor in a standardized exposure setting. All images were read using a Schick dedicated software system (CDR DICOM for Windows v.3.5), and three commonly available non-dedicated software systems (Vix Win 2000 v.1.2; Adobe Photoshop 7.0 and Image Tool 3.0). The defects were measured three times in each image and a consensus was reached among three examiners using the four software systems. The difference between the radiographic measurements was analysed using analysis of variance (ANOVA) and by comparing the measurements from each software system with the dry mandibles measurements using Student's t-test.Results: the mean values of the bone defects measured in the radiographs were 5.07 rum, 5.06 rum, 5.01 mm and 5.11 mm for CDR Digital Image and Communication in Medicine (DICOM) for Windows, Vix Win, Adobe Photoshop, and Image Tool, respectively, and 6.67 mm for the dry mandible. The means of the measurements performed in the four software systems were not significantly different, ANOVA (P = 0.958). A significant underestimation of defect depth was obtained when we compared the mean depths from each software system with the dry mandible measurements (t-test; P congruent to 0.000).Conclusions: the periodontal bone defect measurements in dedicated and in three non-dedicated software systems were not significantly different, but they all underestimated the measurements when compared with the measurements obtained in the dry mandibles.

Densitometry, radiography, and histological assessment of collagen as methods to evaluate femoral bones in an experimental model of osteoporosis

All methods to detect experimental loss of bone present technique limitations. The sensitivities of image and histological analyses to detect the effects of teriparatide in rats with bone loss after ovariectomy were evaluated. All methods were qualitatively valid.The standardization of methods to assess bone loss after ovariectomy is crucial to establish the degree of experimental osteoporosis. In general, methods per image or histological techniques are used. To validate these two ways to determine the degree of bone loss in ovariectomized rats, we evaluated the sensitivities of bone densitometry, conventional radiography, and histological analysis of the area occupied by collagen, detecting the effects of teriparatide treatment in the femur of ovariectomized rats with bone loss.Wistar rats were divided into three groups: a control group, in which the animals were only subjected to laparotomy; an ovariectomized group, in which bilateral removal of the ovaries was performed; and an ovariectomized + teriparatide group, in which bilateral removal of the ovaries was performed, and the animals were treated with 3 mu g/100 g/day of teriparatide. Three months following the ovariectomy, bone densitometry, radiographic densitometry, and histological analysis of the area occupied by collagen fibers were carried out in the femur diaphysis.The bone densitometry revealed 11.2% reduction in femur density; in the conventional radiography, the loss of bone mass was 14.5%, and with the histological analysis, a 40.9% reduction in the area occupied by collagen was detected in the femur diaphysis.In conclusion, histological analysis could not be quantitatively compared with the methods of bone densitometry and conventional radiography; however, all of these methods were qualitatively valid for assessing the loss of bone stemming from ovariectomy and the therapeutic effect of teriparatide in the prevention of osteoporosis.

Association of 3D Reconstruction and Conventional Radiography for the Description of the Appendicular Skeleton of Chelonoidis carbonaria (Spix, 1824)

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

Bone scintigraphy in testicular tumors

Purpose: Testicular tumors do not occur frequently. Primary treatment is surgical, and radiotherapy and chemotherapy can play important roles in cases of metastatic disease. Bone scintigraphy is used largely for early detection of skeletal metastases from several tumors, and conventional radiographic studies are less sensitive than the nuclear technique for such a purpose. The aim of this study was to identify the role of bone scintigraphy in cases of testicular tumors, regardless of the grade. Materials and Methods: The authors examined 28 patients (8 to 52 years old) with proved testicular tumors using Tc-99m MDP (750 MBq; 20 mCi) injected intravenously. Whole-body images were obtained 2 hours later, at 500,000 counts per image. Radiographic studies were obtained to investigate abnormal areas noted on scintigraphy. Results: The results of bone scintigraphy were abnormal in seven cases, consisting of variable but diffuse uptake in the iliac bone on the same side as the affected testicle. MDP uptake was substantial in five of these patients (four seminomas, one nonseminoma; only two radiographic studies were abnormal), and the two other patients had moderate uptake of the radiopharmaceutical (two seminomas; radiographic studies were normal). Metastases were confirmed by biopsy in three cases. Discussion: Early metastases from seminomas can occur through the lymphatic drainage toward the iliac lymph node chain. This could explain these findings. The scintigraphic aspects of the affected iliac bones seem characteristic. Conclusions: Early detection of metastases is very important to ensure the efficacy of radiotherapy and chemotherapy. Bone scintigraphy may play an important role in such cases and seems to be more sensitive than conventional radiography. Testicular tumor metastases should be considered when iliac involvement is observed. Paget's disease should be included in a differential diagnosis.

Bone mineralization among male adolescents: Critical years for bone mass gain

Objective: To verify the behavior of the mineral bone content and density in male adolescents according to age and secondary sexual characters. Methods: 47 healthy adolescents between 10 and 19 years old were assessed according to weight, height, body mass index, puberty stage, calcium intake, bone mineral density and content in the lumbar spine and in the proximal femur. The bone mass was measured through bone densitometries. The intake of calcium was calculated through a 3-day diet. The BMI (body mass index) was calculated with the Quetelet Index and the puberty stage was defined according to Tanner's criteria. The analysis used descriptive statistics such as average and standard deviation, and variance estimates to compare the different age groups. Moreover, the Tukey test was used to determine the significant differences. Results: It was evident that the calcium intake in the different ages assessed has not reached the minimum value of 800 mg. The bone mineral density and content showed an increase after the age of 14, as well as when the teenagers reached the sexual maturation stage G4. The mineralization parameters showed a high level when the teenagers were in the G3 stage, however, without statistical significance. Conclusion: The results indicate an important level of bone mineralization during adolescence. Maturation levels superior to G3 have shown more mineralization. This study proves that the critical years for bone mass gain start after the 14-15 years old or older. Copyright © 2004 by Sociedade Brasileira de Pediatria.

Influence of image filters on the reproducibility of measurements of alveolar bone loss

The reproducibility of measurements of alveolar bone loss on radiographs may be a problem on epidemiologic studies, as they are based on comparisons of the diagnosis of various examiners. The aim of the present research paper was to assess the inter- and intra-examiner reproducibility of measurements of the interproximal alveolar bone loss on non-manipulated digital radiographs and after the application of image filters. Five Oral Radiologists measured the distance between the cementoenamel junction (CEJ) to the alveolar crest or to the deepest point of the bony defect on 12 interproximal digital radiographs of molars and bicuspids of a dry human skull. The digital manipulation and the linear measurements were obtained with the Trophy Windows software (Throphy®). For each image, six different versions were created: 1) non-manipulated; 2) bright-contrast adjustment; 3) negative; 4) negative with brightness-contrast adjustment; 5) pseudo-colored; 6) pseudo-colored with brightness-contrast adjustment. In order to prevent interpretation bias because of the repetition of measurements, the examiners measured the radiographs in a random sequence. The two-way ANOVA test at 5% level of significance to compare the means of readings of the same operator with each filter indicated p<0.05 for the majority of operators, while the comparison between the mean values of operators using the same filter indicated p>0.05 for all filters. Based on the results, we concluded that linear measurements of interproximal alveolar bone loss on digital radiographs are highly reproducible among examiners. Nevertheless, the application of image filters significantly influenced the degree of intra-examiner reproducibility. Some filters even reduced the reproducibility of intra-examiner readings.

Comparison between polyurethanes containing castor oil (Soft Segment) and cancellous bone autograft in the treatment of segmental bone defect induced in rabbits

The aim of this study is to compare polyurethanes containing castor oil (soft segment) in granular form compared to cancellous bone autograft applied to a segmental bone defect. Norfolk adult female rabbits - approximately 13 months of age with a mean body weight of 4.5 kg - are used. In both radial diaphyses, 1 cm osteoperiosteal segmental defects are created. The defect in the left radius is filled with the castor-oil-based polyurethane, and the right one, filled with cancellous bone autograft, collected from the left proximal humerus. The rabbits are euthanazed at 15, 30, 60, and 120 days postsurgery (5 animals/ period), for histological analyses. By radiographic analyses, at these time points, the bone regeneration is more evident and accelerated in the bone defects treated with the cancellous bone autograft. At 120 days postsurgery, the segmental bone defects treated with the cancellous bone autograft are totally reconstituted and remodeled, while the bone defects treated with polyurethane polymer have bone formation of 79%. Histological study shows that the polyurethane acts as a space filler, minimizing the local production of fibrous tissue. No granule degradation, resorption or any inflammatory reaction is detected. Thus, it is possible to conclude that the castor-oil-plant-based polyurethane - in the granule presentation - is biocompatible and osteointegrated, but does not show the same bone regeneration capacity as the cancellous bone autograft. © 2007 SAGE Publications.

Bone mineralization in Brazilian adolescents: The years of maximum bone mass incorporation

Puberty is the fundamental period for bone mass (BM) acquisition. In this period mineralization is found to increase with levels of high bone formation. The critical years of intense bone anabolism deserve special attention, as adequate gain could minimize fracture risk in later years. The objective of this work was to study bone mineral content (BMC) and bone mineral density (BMD) in male adolescents with age bracket and maturation level. Sixty-one healthy male 10 to 19 year-olds were evaluated for calcium intake, weight, stature, BMI, puberty stage and BMC and BMD in the lumbar spine and femur. BM was measured by bone densitometry (DXA). Calcium intake was calculated by recording 3 days diet. Puberty stage was defined as per Tanner. Descriptive statistics was used with means and standard deviations, linear correlation, and analysis of variance for comparison between age groups, and the Tukey test (p<0.05). Linear correlation was positive and indicated body weight as the main correlation variable with BMD in both studied locations (p<0.01). BMC and BMD increased with age, differences were significant from 14 to 15 years, and when adolescents reached Tanner stage G4. These results showed a pronounced increase in bone mineralization, with the years after 14 to 15 being critical for BM acquisition in Brazilian adolescents.

Comparison between inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements

The advances in digital imaging technology in dentistry have provided an alternative to film-based radiography and have given new options to detect periodontal bone loss. The purpose of this study was to compare inverted and unprocessed digitized radiographic imaging in periodontal bone loss measurements. Thirty-five film-based periapical radiographs of patients suffering from moderate to advanced untreated periodontal bone loss associated to lower premolar and molars was selected from the department files, with 40 bone loss areas. The film-based radiographs were digitized with a flatbed scanner with a transparency and radiograph adapter used for transilluminating the radiograph imaging. Digitization was performed at 600 dpi and in gray scale. The images were digitized using Image Tool software by applying image inversion, that is, transformation of radiopaque structures into radiolucent structures and vice-versa. The digital data were saved as JPEG files. The images were displayed on a 15-inch and 24-bit video monitor under reduced room lighting. One calibrated examiner performed all radiographic measurements, three times, from the cementoenamel junction to the most apical extension of the bone loss, in both types of image (inverted and unprocessed). Brightness and contrast were adjusted according to the examiner's individual demand. Intraclass correlation coefficient was used to compare the measurements from both types of images. The means of radiographic measurements, in mm, for inverted and unprocessed digitized imaging were 6.4485 and 6.3790, respectively. The intraclass correlation coefficient was significant (0.99) The inverted and unprocessed digitized radiographic images were reliable and there was no difference in the diagnostic accuracy between these images regarding periodontal bone loss measurements.

Smoking enhances bone loss in anterior teeth in a Brazilian population: A retrospective cross-sectional study

The aim of the present study was to radiographically evaluate the effect of smoking on bone loss resulting from chronic periodontitis. Periapical radiographs were analyzed of 80 patients with chronic periodontitis (40 current or former smokers and 40 never-smokers) that attended a private periodontal practice. The smokers or former-smokers with a minimum consumption of 10 cigarettes/day for a period of over 10 years were selected. Interproximal radiographic bone loss was considered as the distance between the cementum-enamel junction and the alveolar bone crest. Bone loss for smokers was higher than that observed in never-smokers (p < 0.05) (3.33 ± 1.09 mm and 2.24 ± 0.76 mm; mean ± standard deviation for smokers and non-smokers, respectively). When each region of the mouth was comparatively evaluated, it was observed that the smokers' incisors presented the highest bone loss when compared with the other groups of teeth (p < 0.01). Within the limits of the present investigation it can be concluded that smoking enhances the bone loss resulting from periodontitis and that the incisors are the teeth most affected.

Effect of induced diabetes mellitus on alveolar bone loss after 30 days of ligature-induced periodontal disease

Several studies have shown that diabetics are more susceptible to the development of severe periodontal disease. Currently, the use of animal models can be considered a feasible alternative in radiographic assessments of these two pathologies. The purpose of this radiographic study was to evaluate the effect of induced diabetes mellitus on alveolar bone loss after 30 days of ligature-induced periodontal disease. Sixty-four Wistar rats were randomly distributed into four experimental groups. Diabetes was induced in Groups II and IV, while periodontal disease was induced in Groups III and IV; Group I was used as control. In order to perform the radiographic assessment of the specimens, the rats were killed on the 3rd and 30th days of the study. Radiographic measurements were assessed with ANOVA and Tukey's test to determine statistically significant differences (p < 0.05). It was observed that Groups III and IV featured greater bone loss when compared to Groups I and II. Only the diabetic group with periodontal disease (Group IV) featured statistically significant greater bone loss when compared to the other groups. These results suggested that the alveolar bone loss resulting from the periodontal disease installation is greater when associated to the diabetes mellitus.