Evaluation of safe areas for miniscrew use according to various skeletal anomalies with CBCT.

OBJECTIVES: We aimed to determine safe areas to apply miniscrews in the interradicular region of the maxilla and mandible in individuals with various sagittal skeletal malocclusions. MATERIALS AND METHODS: Cone beam-computed tomography images of 159 individuals were used. Individuals were divided into three groups: Class I, Class II, and Class III. In the sagittal plane, 3-6-9-mm apical sections were determined from the alveolar crest apex. The buccal cortical bone thickness, interradicular distance, and buccolingual bone distances were measured. RESULTS: In the buccal cortical bone thickness, we observed statistically significant differences between the classes except for the 1-1 region in the maxilla and all regions and sections in the mandible (p < 0.05). The differences in the buccolingual bone distance between classes were statistically significant, except for the 3-mm and 6-mm sections in the 3-4 and 4-5 regions of the maxilla, the 9-mm sections in the 1-2 and 2-3 regions, the 6-mm and 9-mm sections in the 3-4 region, and the 6-mm section in the 4-5 regions of the mandible (p < 0.05). The differences in the interradicular bone distance were statistically significant between the classes in all regions and sections of the mandible except the 6-mm sections in the 1-2 region and in all sections of the maxilla except the 6-mm sections in the 3-4 region (p < 0.05). CONCLUSIONS: We observed significant differences in the buccal cortical bone thickness, interradicular bone distance, and buccolingual bone distance among individuals. CLINICAL RELEVANCE: Understanding the anatomy of interradicular regions and preventing complications.

Inter radicular bone dimensions in primary stability of immediate molar implants - A cone beam computed tomography retrospective analysis.

PURPOSE: The purpose of the study was to analyze the dimensions of socket morphology, interradicular bone dimensions, root length and morphology, buccal cortical bone thickness and gap defect between the implant bone in mandibular molars with cone beam computed tomography (CBCT) for immediate molar implant (IMI) placement. MATERIALS AND METHODS: Sample sizes of 300 mandibular 1st and 2nd molars were each selected from the CBCT scans by inclusion and exclusion criteria. CBCT measurements were performed for socket size morphology, mesiodistal width, and buccolingual cancellous bone width at the crest at the apex. Width of the buccal cortical plate at the crest and interradicular bone (IRB) at the apex, 3 mm cervical to the apex and 6 mm cervical to the apex. Vertical parameters from the crest to furcation (L1), length from furcation to the apex (L2) and mesiodistal root morphology were measured to analyze the root configuration. RESULTS: All the parameters were analyzed for descriptive statistics for the mean and standard deviation. The majority were of Type B and C socket morphology with peri-implant bone defects of 2-2.5 mm, and the interradicular bone septum (IRB) was moderate for both first molar (1 M) and second molar (2 M) sites, but 2 M was shown to have less IRB than 1 M. Adequate buccal cortical bone thickness of 1.1 mm to 1.4 mm and buccolingual cancellous bone width were measured for both the 1 M and 2 M sites. CONCLUSION: The morphology of the molar extraction socket determines the adequate stability for IMI. In mandibular molar teeth, where interradicular bone is incompetent in providing good primary stability, in addition to interradicular bone, clinicians should look for support from the apical bone and interdental septal bone for attaining primary stability of IMI.

Functional adaptation of interradicular alveolar bone to reduced chewing loads on dentoalveolar joints in rats.

OBJECTIVES: The effects of reduced chewing loads on load bearing integrity of interradicular bone (IB) within dentoalveolar joints (DAJ) in rats were investigated. METHODS: Four-week-old Sprague Dawley rats (N = 60) were divided into two groups; rats were either fed normal food, which is hard-pellet food (HF) (N = 30), or soft-powdered chow (SF) (N = 30). Biomechanical testing of intact DAJs and mapping of the resulting mechanical strains within IBs from 8- through 24-week-old rats fed HF or SF were performed. Tension- and compression-based mechanical strain profiles were mapped by correlating digital volumes of IBs at no load with the same IBs under load. Heterogeneity within IB was identified by mapping cement lines and TRAP-positive multinucleated cells using histology, and mechanical properties using nanoindentation technique. RESULTS: Significantly decreased interradicular functional space, IB volume fraction, and elastic modulus of IB in the SF group compared with the HF group were observed, and these trends varied with an increase in age. The elastic modulus values illustrated significant heterogeneity within IB from HF or SF groups. Both compression- and tension-based strains were localized at the coronal portion of the IB and the variation in strain profiles complemented the observed material heterogeneity using histology and nanoindentation. SIGNIFICANCE: Interradicular space and IB material-related mechanoadaptations in a DAJ are optimized to meet soft food related chewing demands. Results provided insights into age-specific regulation of chewing loads as a plausible "therapeutic dose" to reverse adaptations within the periodontal complex as an attempt to regain functional competence of a dynamic DAJ.

Consideraciones Metodológicas en el Estudio Histomorfométrico del Hueso Interradicular de los Primeros Molares Inferiores de Ratas Wistar / Methodological Considerations in the Histomorphometric Study of the Interradicular Bone of the First Lower Molars of Wistar Rats

El objetivo fue evaluar el volumen óseo BV/TV (%) del hueso interradicular en ratas Wistar: A) en relación a la edad; B) en relación a la zona de estudio en animales de la misma edad. Se utilizó Grupo A) 15 ratas Wistar hembras de 6 (I), 10 (II) y 14 (III) semanas, Grupo B) 9 ratas Wistar macho de 8 semanas. Tras la eutanasia, se extrajeron los maxilares inferiores y se procesaron histológicamente para obtener cortes mesio-distales del primer molar inferior coloreados con H.E. Sobre microfotografías digitales se evaluó el BV/TV (%). El análisis estadístico se realizó en A) mediante ANOVA y Bonferroni test y en B) se calculó el rango (R). Los resultados en A) el BV/TV (%) aumenta significativamente con la edad de los animales; en B) se encontró que el BV/TV (%) varía hasta un 20% si se considera el volumen total y este rango disminuye a 8.3% al estudiar su mitad coronal. En conclusión, el BV/TV (%) del hueso interradicular del primer molar inferior de ratas Wistar varía considerablemente con la edad de los animales y en animales de una misma edad -según se considere evaluar todo el hueso interradicular del espacio alveolar o la mitad superior del mismo-. Los resultados de este trabajo recomiendan emplear animales de la misma edad y realizar mediciones histomorfométricas empleando la mitad coronal de dicho hueso, especialmente en los diseños de periodontitis experimental (AU)

Correlation of radiovisuographic analysis of interdental and interradicular bone loss in furcation involvement of mandibular first molars: A retrospective study.

BACKGROUND AND OBJECTIVES: The presence of furcation involvement represents a formidable problem in the treatment of periodontal disease. Advances in radiographic analysis such as radiovisuographic (RVG) aid in the early diagnosis and treatment planning, which is critical for long-term success. The present investigation aims to correlate the interdental and interradicular bone loss in chronic periodontitis patients so as to explore the potential of interdental bone loss as a rough approximate screening tool for early furcation diagnosis in mandibular first molar. MATERIALS AND METHODS: RVG radiographs with furcation radiolucency in mandibular first molars were selected. The morphometric measurements of mesial, distal interdental bone loss, and interradicular bone loss in mandibular first molars were recorded using RVG. The correlation between mesial and distal interdental bone loss and interradicular bone loss was analyzed. RESULTS: In this retrospective investigation, it was observed that distal interdental bone loss was not significantly different when compared with mesial interdental bone loss. The interradicular bone loss was significantly different when compared with mesial interdental bone loss, whereas on analysis between distal interdental bone loss and interradicular bone loss was also found to be statistically significant. INTERPRETATION AND CONCLUSION: Interdental bone loss was found to be associated with progressive bone destruction in furcation area which suggests that early detection of interdental bone loss can be helpful in predicting future interradicular bone loss.

Influence on interradicular bone volume of Invisalign treatment for adult crowding with interproximal enamel reduction: a retrospective three-dimensional cone-beam computed tomography study.

BACKGROUND: The aim of this study was to use three-dimensional datasets to identify associations between treatment for adult crowding, using Invisalign aligner and interproximal enamel reduction (IER), and changes in the volume of interradicular bone. METHODS: A total of 60 cone-beam computed tomography (CBCT) scans from 30 adult patients (28 women, two men; 30 CBCTs pre-treatment, 30 post-treatment) were examined retrospectively in order to measure bone volume three-dimensionally. The patients' average age was 36.03 ± 9.7 years. The interradicular bone volume was measured with OsiriX at four levels in the anterior tooth areas of the maxilla and mandible. Differences in bone between T0 and T1 were analyzed with IBM SPSS 21.0 using the Wilcoxon test for paired samples. RESULTS: Overall, a slight increase in the quantity of bone was found (0.12 ± 0.73 mm). There was a highly significant increase in bone in the mandible (0.40 ± 0.62 mm; P <  0.001), while in the maxilla there was a slight loss of bone, which was highly significant in the apical third (- 0.16 ± 0.77 mm; P = 0.001). CONCLUSIONS: Overall, treatment for adult crowding using an aligner and IER appears to have a positive effect on interradicular bone volume, particularly in patients with severe grades of the condition (periodontally high-risk dentition). This effect is apparently independent of IER. This is extremely important with regard to the treatment outcome, since IER and root proximity have been matters of debate in the literature and teeth should remain firmly embedded in their alveolar sockets.

Immediate implant placement into fresh extraction socket in the mandibular molar sites: a preliminary study of a modified insertion technique.

BACKGROUND: Immediate implant insertion in mandibular molar extraction sockets raises a series of challenges for clinicians. PURPOSE: This preliminary study demonstrates the use of a modified insertion technique of implant placement at the time of mandibular molar extraction. MATERIALS AND METHODS: Immediate implants were placed at the time of molar extraction in 20 patients; a sulcular buccal incision with releasing periosteal incisions were made around the mandibular molar to be replaced, and implant insertion into the interseptal/interradicular bone was performed. The remnants of roots were atraumatically extracted, and the bony defects around the implant were grafted with synthetic resorbable bone substitute ß- Tricalcium phosphate, and the flap was sutured. Three months later, implants were restored with single crown fixed prostheses. Patients were followed up at 6, 12, and 18 months after insertion using periapical standardized radiographs to monitor the changes in the marginal bone level. RESULTS: Our modified insertion techniques showed an implant survival rate of 95%; one implant failed 4 weeks after insertion. No significant marginal bone loss around the implant was recorded at all times of follow-up. Satisfactory soft issue parameters were achieved. CONCLUSIONS: The combination of immediate implant placement with engagement of the interseptal/interradicular bone, atraumatic extraction of remnant roots, and concomitant regenerative therapy showed preliminary favorable outcomes. However, wider application of this technique for longer following up periods is required for further conclusive recommendations.

Correlation of the interdental and the interradicular bone loss: A radiovisuographic analysis.

BACKGROUND: Presence of furcation involvement indicates advanced periodontitis, and a potentially less-favorable prognosis, for the affected tooth and its diagnosis has always been an enigma. The present study was carried out to measure and correlate the interdental and interradicular bone loss in patients suffering from periodontitis using radiovisuography (RVG) for the purpose of early furcation diagnosis. MATERIALS AND METHODS: A total of 50 patients suffering from chronic generalized periodontitis and with furcation involvement in mandibular molars were selected. Under standardized conditions, RVGs were taken and the morphologic measurements defining the furcation areas were recorded and analyzed. RESULT: Interradicular bone loss of about 0.8 mm or more, was observed in the study subjects only when the bone loss at the interdental area was minimal of 3.7 mm. The correlation between the interradicular and the interdental bone loss was statistically highly significant (T-test, P < 0.001). A stronger correlation was observed in subjects above 40 years of age as compared with the younger subjects. There was not much difference in the degree of correlation between the interradicular and the interdental bone loss when compared in the context of gender. CONCLUSION: The very first millimeter of interradicular bone loss was seen when the interdental bone loss was around 4 mm. Therefore, to detect the earliest lesions of furcations, the interdental bone loss can be kept as an approximate guide for the comprehensive diagnosis and management of such sites/patients. The current investigation paves the path for future longitudinal studies with larger samples to ascertain these findings.