Introduction: The primary concern in the placement of ramal bone screws is the blind nature of the procedure, as there is a thick, mobile layer of soft tissue over the bone; also, the ramus is not a uniplanar structure but is swerving like a propeller blade. The purpose of this study was to evaluate the possibility of establishing clinical guidelines based on visible dental and soft-tissue landmarks for safe, reliable, and accurate insertion of ramal bone screws. Aims and Objectives: Our primary objective was to evaluate the angle formed between the appropriate direction of ramal-implant placement and the line tangential to the buccal surfaces of the first and second permanent molars. Our secondary objective was to evaluate the average distance of the neurovascular bundle from the tip of the bone screw. Materials and Methods: We obtained 80 cone beam computed tomography (CBCT) samples, marked reference lines and points on selected axial and coronal sections, and evaluated the following parameters using the software’s linear- and angular-measurement device: the angle between the appropriate direction of ramal bone screw placement and the line tangential to the buccal surfaces of the first and second permanent molars; and the proximity of the bone screw to the neurovascular bundle. Results: The angle between the constructed line of insertion and the occlusal line, as evaluated from our study, was 19.04 (SD ± 6.89) degrees. The proximity of the neurovascular bundle from the screw is 7.1773 (SD ± 1.73988) mm. Conclusion: We can conclude that ramal bone screws can be placed with a comfortable margin of safety.
Objective To determine the reliability of Computer Assisted Digital Cephalometric Analysis System (CADCAS) in terms of landmark identification on the values of cephalometric measurements in comparison with those obtained from original radiographs. Materials and Methods The study material consisted of Twenty five lateral cephalograms selected randomly, 16 cephalometric points together with 10 angular and 5 linear cephalometric measurements. The landmarks were manually picked on the tracing & the measurements of X &Y axis done with reference grid. The same tracing was digitized & image loaded in the software (ViewBox 3.1.1) was checked for the magnification (metal ruler) & distortion. The second part of the study compared manual and the CADCAS since the landmarks were manually digitized on screen as against the manually picked ones on the tracing paper. The x and y-coordinates for 16 landmarks were measured, mean and standard deviation calculated, linear and angular measurements compared. Statistical Analysis A paired t-test was done to calculate the statistical significance of the differences. Intraclass reliability coefficient (signifying reproducibility) of the variable was recorded. The observations were tabulated and analysis was done using the paired t test at a P value <0.05. Results Out of 47 variables looked for, 21 showed statistical significance. Direct digitization onscreen (CADCAS) was the quickest and least tedious method. CADCAS was unreliable with linear measurements involving bilateral structures such as Gonion & Articulare. Conclusions Both the methods are equally reliable and reproducible. The intra-class reliability coefficient of all variables differed only slightly, which is not clinically significant.
Introduction: Buccal shelf bone screws have become increasingly popular as a preferred method of skeletal anchorage in the mandibular arch. Anatomic variations and clinical experience suggest that width and slope of the bone at buccal shelf vary in different population groups, with some individual variations. Aims and Objectives: The objective of this study was to evaluate angulation of the bone screw of mandibular buccal shelf area, total bone width, thickness of the cortical bone, and proximity to neurovascular structures. Materials and Methods: Cone-beam computed tomography scans were used to obtain measurements of the buccal shelf region of 35 patients (18 females, 17 males; mean age, 23.6 years). Measurements were taken at three locations (L1, L2, and L3) and total bone width was measured at two levels from the cementoenamel junction (CEJ, H1 and H2). Bone screws were virtually placed and their proximity evaluated from digitally traced inferior alveolar neurovascular bundle. Results: Permissible angulation for placement of buccal shelf bone screw considering the safety distance from the root and avoiding excessive buccal projection to minimize cheek irritation was found to be 74.48 (SD ± 4.26). Total bone width was maximum at the distobuccal cusp of mandibular second molar (L3H2; 6.40 ± 1.35) when measured at the level of 8 mm from the CEJ. Bone screws were well within the safety range from causing any iatrogenic damage to the inferior alveolar neurovascular bundle at all the three aforementioned locations. Conclusion: Thus, area buccal to the mandibular second molar region seems to be the most favorable site for placement of buccal shelf bone screws in Indian patients.
Introduction The palatal bone is a suitable site for mini-implant placement due to it being a “rootless area” with dense bone. This application has increased with mini-implant-assisted rapid palatal expansion becoming the preferred method of expansion. It is necessary to measure the vertical bone height with a reasonable accuracy, at the implant insertion site, to utilize the maximum available bone support, and to avoid the risk of perforations. As an accepted method, full-volume cone-beam computed tomography (CBCT) scan is advised for the same. This requires an additional procedure, further, radiation exposure, and cost to the patient. The aim of the study was to establish the utility of lateral cephalogram as a simple and reliable method to measure palatal bone thickness for placement of mini-implants in the 1st premolar and 1st molar region, which are the most common sites of mini-implant placement. Materials and Methods A total of 30 CBCT scans and digital lateral cephalograms of patients were selected and analyzed at the 1st premolar and molar region and were statistically evaluated using Student’s t-test and Wilcoxon rank-sum test. Results The results obtained indicated a highly significant correlation between the measurements obtained on lateral cephalograms at both the 1st premolar and 1st molar areas, P < 0.001. Conclusion The data presented show that lateral cephalometry provides a reliable assessment of the quantity of vertical bone for paramedian insertion of a palatal implant.
Incorporation of mini screws in a conventional RPE appliance transforms it into a MARPE appliance. Mini screws ensure maximum skeletal expansion, keeping the dental expansion and resultant side effects to a minimum. Various designs have been recommended by authors around the globe; exclusively bone borne, teethbone borne and tissue-bone borne with two/ four mini screws in the assembly.Paramedian area 3 mm lateral to the suture in 1 st premolar region is considered the most appropriate site for placement of mini screws. Anterior screws are placed in the rugae area while posterior screws in the para-midsagittal area. This article (case series) describes three cases treated with MARPE appliance designs and protocols.
Introduction: Enamel integrity gets affected by the presence of micro-cracks in it and they can further create problems like stains and the accumulation of plaque on the fractured surfaces. Avoiding such iatrogenic damage to the enamel surface has been a constant challenge even with the use of metal brackets. Creating a fracture line in the base of the bracket leads to the formation of a 'weak zone'. This allows the bracket to collapse in a mesiodistal direction when debonding forces are applied rather than shattering the bracket into tiny multiple pieces. Thus, removal of the bracket having such a 'weak zone' created by making a groove in it before bracket removal arguably leaves the major amount of resin on the tooth and therefore causes less stress on enamel. This study plans to evaluate the expected beneficial effect of 'scoring' the base of the ceramic bracket before bracket removal.Aim: To evaluate and compare the occurrence of micro-cracks in enamel observed before bonding and after debonding of various types of ceramic brackets. Results:The difference between scored monocrystalline ceramic brackets and unscored monocrystalline ceramic brackets of both the AO and Ormco groups is not significant statistically (p = 0.096). There is a significant difference in scoring of ARI and enamel micro-cracks development. The difference of length and width between the groups (A and B) is statistically insignificant. Conclusion:Post debonding, there was no difference significantly in the length or width of enamel micro-cracks between AO monocrystalline ceramic brackets (group A) and Ormco monocrystalline ceramic brackets (group B).
Objective: To evaluate and compare the force and load deflection rate generated by differing unit displacement through 1 to 4 mm of springs that vary in design (Double Delta Closing Loop, Double Vertical T Crossed Closing Loop, Double Vertical Helical Closing Loop and Ricketts Maxillary Retractor), constituting wire materials (stainless steel and beta titanium), and wire dimensions (0.017" × 0.025" and 0.019" × 0.025"). Materials and methods: Computer-assisted design (CAD) model of the said loop springs was created and converted to the finite element method (FEM). The boundary conditions assigned were restraining anterior segment of the loops in all the 3 axes and displacement of the posterior segment progressively only along the x-axis in increments of 1, 2, 3, and 4 mm. Force and load deflection rate were calculated for each incremental displacement. Results: For all loop designs, force and load deflection rate increased with incremental displacement. Loop springs of beta titanium and 0.017" × 0.025" dimension showed lesser force and load deflection rate than those of stainless steel and 0.019" × 0.025", respectively. Ricketts Maxillary Retractor showed the least force and load deflection rate. Comparable force and load deflection values were found for 0.017" × 0.025" Double Vertical T Crossed Loop and 0.019" × 0.025" Double Vertical Helical Closing Loop. Conclusions: Variations in wire dimensions, materials, and designs have a profound effect on force and load deflection rate of the different loop springs studied.
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