Joseph M. Caruso

A Comparison of Cone-Beam Computed Tomography and Direct Measurement in the Examination of the Mandibular Canal and Adjacent Structures

INTRODUCTION The purpose of this investigation was to assess the ability of cone-beam computed tomography (CBCT) scanning to measure distances from the apices of selected posterior teeth to the mandibular canal. Measurements were taken from the apices of all posterior teeth that were superior to the mandibular canal. METHODS A pilot study was performed to determine the scanning parameters that produced the most diagnostic image and the best dissection technique. Twelve human hemimandibles with posterior teeth were scanned at .20 voxels on an I-CAT Classic CBCT device (Imaging Sciences International, Hatfield, PA), and the scans were exported in Digital Imaging and Communications in Medicine (DICOM) format. The scans were examined in InVivo Dental software (Anatomage, San Jose, CA), and measurements were taken from the apex of each root along its long axis to the upper portion of the mandibular canal. The specimens were dissected under a dental operating microscope, and analogous direct measurements were taken with a Boley gauge. All measurements were taken in triplicate at least 1 week apart by one individual (TSK). The results were averaged and the data separated into matching pairs for statistical analysis. RESULTS There was no statistical difference (alpha = .05) between the methods of measurement according to the Wilcoxon matched pairs test (p = 0.676). For the anatomic measurements, the intra-rater correlation coefficient (ICC) was .980 and for the CBCT it was .949, indicating that both methods were highly reproducible. Both measurement methods were highly predictive of and highly correlated to each other according to regression and correlation analysis, respectively. CONCLUSIONS Based on the results of this study, the I-CAT Classic can be used to measure distances from the apices of the posterior teeth to the mandibular canal as accurately as direct anatomic dissection.

The fracture strength of ceramic brackets: a comparative study.

Recent demand for esthetic brackets has led to the development and use of ceramic brackets in orthodontics. The purpose of this study was to compare the fracture strength of different ceramic brackets under different surface conditions and ligation methods using a torsional wire bending force. Five different bracket types (two polycrystalline, two single-crystal, and one metal) were tested using elastic and wire ligation, with half being scratched and the other half remaining unscratched. Results showed a significant difference between bracket types and surface conditions. Non-scratched single-crystal brackets had higher fracture strengths and slightly higher fracture loads than polycrystalline brackets. However, single-crystal brackets were significantly adversely affected by surface damage (scratching), while polycrystalline brackets were not significantly affected by surface damage. The fracture behavior of ceramic brackets followed the Griffith model where fracture strength decreased following surface damage.

A cephalometric study of the Class II correction effects of the Eureka Spring.

The effect of the Eureka Spring (ES) appliance was investigated on 37 consecutively treated, noncompliant patients with bilateral Class II malocclusions. Lateral cephalographs were taken at the start of orthodontic treatment (T1), at insertion of the ES (T2), and at removal of the ES (T3). The average treatment interval between T2 and T3 was four months. The Class II correction occurred almost entirely by dentoalveolar movement and was almost equally distributed between the maxillary and mandibular dentitions. The rate of molar correction was 0.7 mm/mo. There was no change in anterior face height, mandibular plane angle, palatal plane angle, or gonial angle with treatment. There was a 2 degrees change in the occlusal plane resulting from intrusion of the maxillary molar and the mandibular incisor. Based on the results in this sample, the ES appliance was very effective in correcting Class II malocclusions in noncompliant patients without increasing the vertical dimension.

Deformation of metal brackets: a comparative study.

The purpose of this study was to determine the effect of material and design on the force and stress required to permanently deform metal brackets. Fourteen types of metal brackets were categorized according to raw material composition, slot torque degree, and wing type. Five types of raw materials, three types of slot torque degree, and four types of wing design were tested using an archwire torque test developed by Flores. An analysis of variance (ANOVA) and t-test showed that all three categories had a significant effect on the force and stress needed to permanently deform metal brackets. Of the three, raw material had the greatest effect on the amount of force. Results showed that 17-4PH and 303S had higher yield strengths and regular twin brackets had higher resistance to deformation. Also, as slot torque degree increased, brackets deformed with less force. Result confirmed that brackets requiring the greatest stress to permanently deform were made of steel with the greatest hardness.

Recombinant Human Bone Morphogenetic Protein 2 Combined With an Osteoconductive Bulking Agent for Mandibular Continuity Defects in Nonhuman Primates

PURPOSE Recombinant human bone morphogenetic protein 2 (rhBMP-2) is an option for reconstructing mandibular continuity defects. A challenge of this technique is the need to maintain sufficient space to avoid compression of the defect. A compression-resistant matrix (CRM) provides a bulking agent that provides support during the bone formation phase. MATERIALS AND METHODS Thirteen Rhesus Macaque monkeys were used to evaluate different forms of an osteoconductive bulking agent compared with an absorbable collagen alone placed into a critical-sized mandibular defect. A total of 5 groups (26 defects) were evaluated: group A, rhBMP-2/absorbable collagen sponge (ACS) (1.5 mg/mL); group B, rhBMP-2/ACS with ceramic granules (15% hydroxyapatite/85% β-tricalcium phosphate) at 1.5 mg/mL; group C, rhBMP-2 (2.0 mg/mL) with a CRM; group D, rhBMP-2 (0.75 mg/mL) with a CRM; and group E, a CRM alone. RESULTS Histology and micro computed tomography were used to evaluate and compare new bone formation in the defects. The reconstructed bone was evaluated with regard to the new bone formation, residual voids, and density. Animals treated with the CRM and rhBMP-2 at 2.0 mg/mL (group C) showed significantly higher amounts of new bone formation, bone density, and reduced voids when compared with rhBMP-2 and ACS (1.5 mg/mL) (P < .05). CONCLUSION The carrier system CRM combined with rhBMP-2 and a reconstruction plate results in significantly higher bone density and better space maintenance than rhBMP-2 combined with ACS in a nonhuman primate mandibular bone repair model.

Accuracy of computer-guided surgery: A comparison of operator experience

STATEMENT OF PROBLEM Even though high-precision technologies have been used in computer-guided implant surgery, studies have shown that linear and angular deviations between the planned and placed implants can be expected. PURPOSE The purpose of this study was to evaluate the effect of operator experience on the accuracy of implant placement with a computer-guided surgery protocol. MATERIAL AND METHODS Ten surgically experienced and 10 surgically inexperienced operators participated in this study. Each operator placed 1 dental implant (Replace Select) on the partially edentulous mandibular model that had been planned with software by following a computer-guided surgery (NobelGuide) protocol. Three-dimensional information of the planned and placed implants were then superimposed. The horizontal and vertical linear deviations at both the apex and platform levels and the angular deviation were measured and compared between the experienced and inexperienced groups with the independent t test with Bonferroni adjustment (α=.01). The magnitude and direction of the horizontal deviations were also measured and recorded. RESULTS No significant differences were found in the angular and linear deviations between the 2 groups (P>.01). Although not statistically significant (P>.01), the amount of vertical deviation in the coronal direction of the implants placed by the inexperienced operators was about twice that placed by the experienced operators. Overall, buccal apical deviations were most frequent and of the highest magnitude. CONCLUSIONS When a computer-guided protocol was used, the accuracy of the vertical dimension (depth of implant placement) was most influenced by the operators level of experience.

A study of craniofacial growth in infant heart transplant recipients receiving cyclosporine

BACKGROUND Cyclosporine is an effective immunosuppressive drug that has found widespread application in organ transplantation. However, a few studies have implicated cyclosporine as adversely affecting craniofacial growth in the pediatric population. The purpose of this study was to evaluate the possible untoward effects of cyclosporine long-term on craniofacial growth in a group of infant heart transplantation recipients. METHODS A prospective group (n = 28) of 18 Caucasian (white) children (9 female and 9 male, ages 4-10 years) and 10 Hispanic children (3 female and 7 male, ages 4-10 years) were evaluated. No attempt was made for either study group to delineate on individuals specific country of origin. None of the subjects had undergone orthodontic therapy. All subjects had heart transplantations before 6 months of age and followed the Loma Linda University International Pediatric Heart Transplantation Immunosuppression protocol. The primary immunosuppression agent was cyclosporine with azathioprine or methotrexate. Rescue therapy for graft rejection consisted of glucocorticoid and/or polyclonal antibody therapy. None of the subjects received the immunosuppressant tacrolimus (FK506). Using lateral cephalometric radiography, seven skeletal angular measurements (SNA, SNB, ANB, GoGn-SN, NA-Pog, ArGoMe, NPog-AB) were examined and compared to contemporary growth standards. Hand/wrist radiographs were evaluated for bone age. Also, longitudinal height, weight, and head circumference data was obtained and compared to standardized growth and development curves. RESULTS Descriptive statistics were used to summarize the data. Cephalometrically, 86% (N = 24), showed minor deviation from mean normative values. Four of the subjects (14%) exhibited cephalometric measures indicative of individuals with a vertical growth pattern. Analysis of the hand/wrist radiographs showed all but one subject to have normal bone age. Height, weight, and head circumference data revealed a wide range of growth percentiles for the entire group with mean percentiles in the range of 25% to 50%. CONCLUSIONS The findings of this pilot study indicated that, in general, skeletal growth of the craniofacial complex as well as axial skeletal growth was not statistically significantly altered by the immunosuppressive regimen of cyclosporine over the time period evaluated. Further longitudinal data of this studys subjects may shed more light on the possible adverse effects of cyclosporine on craniofacial growth and development in spite of the fact that no untoward correlation was found over the time period studied.

Periodontal Health of Anterior Teeth with Two Types of Fixed Retainers

OBJECTIVE To compare the periodontal health of maxillary and mandibular anterior teeth retained with two types of fixed retainers. MATERIALS AND METHODS A fixed straight retainer (SR) group had 39 subjects, and a fixed wave retainer (WR) group had 35 subjects. Subjects were between the ages of 13 and 22 years and had been in fixed retention for 2 to 4 years. Pocket probing depths, bleeding on probing, plaque index, calculus index, recession, and gingival crevicular fluid volume were compared between the two retainer groups. A four-question oral hygiene survey was given to each subject. The Mann-Whitney U-test and Fisher exact test was used to analyze the data. RESULTS There was no clinically significant difference between the retainer groups regarding plaque index, gingival crevicular fluid volume, calculus index, recession, bleeding on probing, and pocket probing depths. A statistically significant increase in the reported frequency of flossing (P  =  .006) and ease of flossing (P < .001) was associated with the WR group. There was no significant difference between the groups in reported frequency of brushing and comfort of the retainer. CONCLUSIONS Under the conditions of this study, no clinical difference was found in the periodontal health of anterior teeth retained with a SR or WR for a period of 2 to 4 years. Subjects in the WR group reported an increase in frequency and ease of flossing.

The effect of changes in primary attending doctor coverage frequency on orthodontic treatment time and results

OBJECTIVE To determine whether changes in primary attending (PA) doctor coverage frequency caused an increase in orthodontic treatment time or a decrease in the quality of treatment results in a postgraduate orthodontic clinic. The effect of T1 Peer Assessment Rating (PAR) scores on PA doctor coverage frequency, treatment times, and results was also evaluated. MATERIALS AND METHODS A sample of 191 postorthodontic subjects was divided into three groups based on PA doctor coverage (high, medium, or low). Treatment times, treatment results, and other variables were compared between the three PA coverage groups. Additionally, the sample was divided into three groups based on T1 PAR scores. Attending coverage frequency, treatment times, and results were compared between the T1 PAR groups. RESULTS No statistically significant differences were found in treatment time (P  =  .128) or results (P  =  .052). There were no statistically significant differences in the mean scores for T1 PAR (P  =  .056), T2 PAR (P  =  .602), patient age at T1 (P  =  .747), total appointments (P  =  .128), missed appointments (P  =  .177), or cancelled appointments (P  =  .183). Statistically significant differences were found between the low T1 PAR group and the medium and high T1 PAR groups (attending coverage, P  =  .008; results, P < .001; treatment time, P  =  .001). CONCLUSIONS Under the conditions of this study, variations in PA doctor coverage frequency did not lengthen orthodontic treatment or reduce the quality of treatment results. Low T1 PAR scores were associated with less PA coverage, less change in PAR, and shorter treatment times.

Establishing cephalometric norms for a Mexican population using Ricketts, Steiner, Tweed and Arnett analyses

Objective: Most existing cephalometric analyses are based on norms for the Caucasian population. Therefore, they cannot be properly applied for Latin-American (Hispanic) patients. It is the purpose of this study to establish specific cephalometric standards for a Mexican ethnic group, using the Ricketts, Steiner, Tweed and Arnett analyses. Materials and Methods: Lateral cephalograms of 100 non-growing patients which consists of 50 females and 50 males with native Mexican features and born in the central regions of Mexico, were traced manually and with the Quick Ceph Image Pro TM computer program. Lateral cephalograms of another subset of 30 patients with pleasant profiles (19 females and 11 males) were traced and Arnett Facial Analysis was performed. Results were statistically analyzed with the t-value, P value ( P Results: The statistical results of these cephalometric norms for a Hispanic population showed significant differences in the upper and lower incisors, facial axis and interincisal angles as well as other cephalometric measurements when compared to the Caucasian norms. Conclusion: These cephalometric norms can be applied for Native Americans from the USA and Latin-Americans from Central and South American countries due to the strong anthropometric, facial and ethnic similarities to the Mexican population.