Cláiton Heitz

Dimensional error of selective laser sintering, three-dimensional printing and PolyJet™ models in the reproduction of mandibular anatomy

BACKGROUND Selective laser sintering (SLS), three-dimensional printing (3DP) and PolyJet are rapid prototyping (RP) techniques to fabricate prototypes from virtual biomedical images. To be used in maxillofacial surgery, these models must accurately reproduce the craniofacial skeleton. PURPOSE To analyze the capacity of SLS, 3DP and PolyJet models to reproduce mandibular anatomy and their dimensional error. MATERIAL Dry mandible, helical CT images, SLS, 3DP and PolyJet prototypes, and digital electronic caliper. METHODS Helical CT images were acquired from a dry mandible (criterion standard) and manipulated with the InVesalius software. Prototypes were produced using SLS, 3DP and PolyJet techniques. Thirteen linear measurements of each prototype were made and compared with the dry mandible measurements. RESULTS The results showed a dimensional error of 1.79%, 3.14% and 2.14% for SLS, 3DP and PolyJet models, respectively. The models satisfactorily reproduced anatomic details and the SLS and PolyJet prototypes showed greater dimensional precision and reproduced mandibular anatomy more accurately than the 3DP model. CONCLUSIONS The SLS prototype had a greater dimensional accuracy than the PolyJet and 3DP models. The PolyJet technique reproduced anatomic details of the mandible more accurately.

Bone tissue microscopic findings related to the use of diode laser (830etam) in ovine mandible submitted to distraction osteogenesis

PURPOSE To analyze the microscopic characteristics of the effect of Gallium-Aluminum Arsenid diode laser (GaAlAs - 830etam) applied during the activation and consolidation period to ovine mandibles submitted to distraction osteogenesis. METHODS Eighteen sheep underwent surgery in order to have bone distractors implanted in the left side of the jaw area. They were divided into three groups: 1 - Control; 2 - Laser irradiation during the activation period; 3 - Laser irradiation during the fixation period. The irradiation was carried out in five sessions, on every other day, with 4,0J/cm(2) doses applied to four pre-established areas, totaling 16J per session. After four days of latency under post-operative care, ten days of distractor activation (at 1mm/day) and twenty-one days of fixation the animals were sacrificed and the devices removed for microscopic analysis. RESULTS The groups that received laser irradiation (GaAlAs) presented a greater amount of mineralized bone trabeculae when compared to the Control Group. Despite that, cartilaginous tissues were also found in Group 2. CONCLUSION The laser has been more favorable when used in the consolidation period, after bone elongation.

Calcitonin: A non-invasive giant cells therapy

This paper reports four cases of central giant cell granuloma (CGCG) treated with calcitonin, attesting the efficacy and safety of its use as the chosen therapy for large CGCG. Four patients presenting CGCG treated with calcitonin were included in this study. Salmon calcitonin was administered for 6-28 months. It was observed determination of clear lesion limits for surgery, reduction and limitation of lesions. In aggressive cases, the calcitonin therapy was an excellent option, since it does not harm the patient, and a far less aggressive, complementary surgery may be performed in certain cases, avoiding life-long sequelae.

Comparative histomorphometric analysis between α-Tcp cement and β-Tcp/Ha granules in the bone repair of rat calvaria

This study compared the effect of two bioceramics on the process of bone repair: α-tricalcium phosphate (α-TCP) cement and β-tricalcium phosphate hydroxyapatite particles (β-TCP/HA). Calvarial defects were created in 50 rats, divided into two groups (α and β/HA). Software was used at 7, 21, 60, 90 and 120 days to assess bone formation. Mean new bone formation rates were as follows: α group, 1.6% at 7 days, 5.24% at 21 days, 24% at 60 days, 30.21% at 90 days and 50.59% at 120 days; β/HA group, 1.94% at 7 days, 2.53% at 21 days, 12.47% at 60 days, 26.84% at 90 days and 38.82% at 120 days; control group, 0.15% at 7 days, 10.12% at 21 days, 15.10% at 60 days, 18.94% at 90 days, 48.50% at 120 days. Both materials are osteoconductive and biocompatible. Perhaps the larger rate of new bone formation observed in the α-TCP group, it also occurs in the β-TCP/HA group within a longer time period.

A preliminary study of hardness and modulus of elasticity in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy

Objectives: To investigate the quality of newly formed bone in sheep mandibles submitted to distraction osteogenesis and low-level laser therapy (LLLT), based on hardness and modulus of elasticity values. The ideal moment for laser application (during the latency/activation period vs. during the bone consolidation period) was also evaluated. Computed tomography imaging was used to assess relapse as a result of early device removal. Study design: Extraoral distraction devices were placed in five sheep so as to achieve 1.5 cm of lengthened bone in 60 days. Distraction devices were removed 50, 40, and 33 days after surgery. Four animals were treated with LLLT, at different times, and one was used as control (no LLLT). Results: When applied during the bone consolidation period, LLLT caused an increase in hardness and modulus of elasticity values. On the other hand, animals irradiated with LLLT during the latency/activation period presented a delay in bone healing. A period of consolidation of 13 days (early device removal) was associated with relapse. Conclusions: Nanoindentation tests were able to detect slight abnormalities in bone metabolism and proved to be important tools for the assessment of bone quality following distraction osteogenesis. LLLT provided increased benefits when applied during the bone consolidation period, once it promoted an increase in hardness and modulus of elasticity values. According to our results, the bone consolidation period should be of at least 3 weeks, so as to prevent relapse. Key words: Osteogenesis distraction, low-level laser therapy, elastic modulus, hardness tests.

Is nevoid basal cell carcinoma syndrome really so rare? Proposal for an investigative protocol based on a case series.

Because the initial clinical suspicion of NBCCS isoften triggered by oral manifestations, the presence ofKOT, and other features of the syndrome (cleft palate,maxillary hypoplasia, mandibular hyperplasia, higharched palate, etc), oral surgeons play an importantrole in recognizing and diagnosing them.

IS 3D-CT REFORMATION USING FREE SOFTWARE APPLICABLE TO DIAGNOSIS OF BONE CHANGES IN MANDIBULAR CONDYLES?

Objectives: This study evaluated the agreement of computed tomography (CT) imaging using 3D reformations (3DR) with shaded surface display (SSD) and maximum intensity projection (MIP) in the diagnosis of bone changes in mandibular condyles of patients with rheumatoid arthritis (RA), and compared findings with multiplanar reformation (MPR) images, used as the criterion standard. Material and Methods: Axial CT images of 44 temporomandibular joints (TMJs) of 22 patients with RA were used. Images were recorded in DICOM format and assessed using free software (ImageJ). Each sample had its 3DR-SSD and 3DR-MIP results compared in pairs with the MPR results. Results: Slight agreement (k = 0.0374) was found in almost all comparisons. The level of agreement showed that 3DR-SSD and 3DR-MIP yielded a number of false-negative results that was statistically significant when compared with MPR. Conclusions: 3DR-SSD or 3DR-MIP should only be used as adjuvant techniques to MPR in the diagnosis of bone changes in mandibular condyles.

Histologic and Biomechanical Evaluation of 2 Resorbable-Blasting Media Implant Surfaces at Early Implantation Times

This study evaluated 3 implant surfaces in a dog model: (1) resorbable-blasting media + acid-etched (RBMa), alumina-blasting + acid-etching (AB/AE), and AB/AE + RBMa (hybrid). All of the surfaces were minimally rough, and Ca and P were present for the RBMa and hybrid surfaces. Following 2 weeks in vivo, no significant differences were observed for torque, bone-to-implant contact, and bone-area fraction occupied measurements. Newly formed woven bone was observed in proximity with all surfaces.

Submandibular myofibroma: a case report

PurposeMyofibroma is a rare benign spindle cell neoplasm, and the aim of the present study was to carry out a literature review and present a clinical case of a patient with a myofibroma in the submandibular region and its management.ConclusionsDiagnosis of myofibroma can be reached by a histopathologic and immunohistochemical analysis and surgical excision is the treatment of choice.

Chondroma in temporomandibular region—case report and therapeutic considerations

PurposeChondromas are benign tumors composed of mature hyaline cartilage. These tumors are quite common in the bones of the hands and feet but extremely rare in jaw bones, and few such cases are reported in the literature. The aim of the present study was to carry out a literature review and present a clinical case of a patient with a chondroma in the right mandibular condyle treated with excision of the tumor.ConclusionsThe importance of early diagnosis and treatment in order to impede or minimize any lasting effects is discussed.