Claudio Costa

Comparative study of two autogenous graft techniques using piezosurgery for sinus lifting

PURPOSE Maxillary sinus lifting is a technique, in which, a possible complication is sinus membrane perforation. The aim of this study was to compare two techniques using ultrasound surgery to perform autogenous graft for maxillary sinus lifting. METHODS Ten rabbits were used in the study, one of them did not undergo surgery. The other nine rabbits had their maxillary sinuses filled with autogenous bone grafts collected from the external skull diploe in particulate form on the right side, and shaved on the left side, both with ultrasonic device. Data on bone density in left and right maxillary sinus, obtained by computed tomography in transverse and longitudinal sections, recorded 90 days after the grafts, were statistically compared. RESULTS There were no statistically significant differences between the two techniques that used shaved and particulate bone collected by means of ultrasonic device from rabbit skulls. CONCLUSION Assessment of operative procedures led to the conclusion that piezoelectric ultrasound was shown to be a safe tool in the surgical approach to the maxillary sinus of rabbits, allowing sinus membrane integrity to be maintained during surgical procedures.

Assessment of Bone Healing in Rabbit Calvaria Grafted with Three Different Biomaterials

This study evaluated the bone regeneration process in rabbit calvaria induced by three types of biomaterials: two xenogenous, consisting of deproteinized bovine bone, while the other was alloplastic, based on biphasic calcium phosphate. Five New Zealand white rabbits weighing between 2,900 and 3,500 g were submitted to four standard 8 mm-diameter perforations at the parietal bone. Three perforations were filled with three grafts and biomaterials, two of them received bovine Bio-Oss® and Endobon® Xenograft Granules, and the other consisted of fully alloplastic Straumann® Bone Ceramic. The fourth remaining cavity was used as control with coagulum. After eight weeks, the animals were sacrificed, and the samples were prepared for morphometric and qualitative analysis. The cavities filled with alloplastic biomaterials showed higher percentages of newly formed bone (p<0.05), while the cavities with xenogenous biomaterials showed higher amount of residual graft (p<0.05). Although the results showed greater bone formation with Straumann® Bone Ceramic, further studies are required to prove which is the more effective biomaterial for bone induction process.

Sensitivity and Specificity of Radiographic Methods for Predicting Insertion Torque of Dental Implants

BACKGROUND Subjective radiographic classifications of alveolar bone have been proposed and correlated with implant insertion torque (IT). The present diagnostic study aims to identify quantitative bone features influencing IT and to use these findings to develop an objective radiographic classification for predicting IT. METHODS Demographics, panoramic radiographs (taken at the beginning of dental treatment), and cone-beam computed tomographic scans (taken for implant surgical planning) of 25 patients receiving 31 implants were analyzed. Bone samples retrieved from implant sites were assessed with dual x-ray absorptiometry, microcomputed tomography, and histology. Odds ratio, sensitivity, and specificity of all variables to predict high peak IT were assessed. RESULTS A ridge cortical thickness >0.75 mm and a normal appearance of the inferior mandibular cortex were the most sensitive variables for predicting high peak IT (87.5% and 75%, respectively). A classification based on the combination of both variables presented high sensitivity (90.9%) and specificity (100%) for predicting IT. CONCLUSIONS Within the limitations of this study, the results suggest that it is possible to predict IT accurately based on radiographic findings of the patient. This could be useful in the treatment plan of immediate loading cases.

Evaluation of bone alterations in the jaws of HIV-infected menopausal women.

The advent of highly active antiretroviral therapy (HAART) has caused a reduction in mortality, thus contributing to an increase in the number of women with HIVࢧAIDS who reach the climacteric period, experience decline in ovarian function, and develop complications of viral infection and HAART, which can accelerate bone loss. The aim of this study was to detect possible alterations in the jaws of HIV-infected women by panoramic radiography. The study comprised a total of 120 women above 40 years of age who were divided into the following two groups: women who are HIV positive (Group I) and women with no known HIV infection (Group II). Measurement of the following three radiomorphometric indexes was performed by panoramic radiography: Mental Index (MI), Panoramic Mandibular Index (PMI) and Antegonial Depth (AD). A total of 70% of women in the control group and 50% of women in the HIV group were in the postmenopausal period, and the average values of both MI (p = 0.0054) and AD (p < 0.0001) for this period were lower in the HIV group than in the control group. For patients who were in the premenopausal period, the average AD was lower in the HIV group than in the control group (p = 0.0003). Despite the difference in the average age between groups, greater bone resorption in the mandible was found in the group of HIV-positive women.

Assessment of alveolar bone marrow fat content using 15 T MRI

OBJECTIVES Bone marrow fat is inversely correlated with bone mineral density. The aim of this study is to present a method to quantify alveolar bone marrow fat content using a 15 T magnetic resonance imaging (MRI) scanner. STUDY DESIGN A 15 T MRI scanner with a 13-mm inner diameter loop-gap radiofrequency coil was used to scan seven 3-mm diameter alveolar bone biopsy specimens. A 3-D gradient-echo relaxation time (T1)-weighted pulse sequence was chosen to obtain images. All images were obtained with a voxel size (58 µm3) sufficient to resolve trabecular spaces. Automated volume of the bone marrow fat content and derived bone volume fraction (BV/TV) were calculated. Results were compared with actual BV/TV obtained from micro-computed tomography (CT) scans. RESULTS Mean fat tissue volume was 20.1 ± 11%. There was a significantly strong inverse correlation between fat tissue volume and BV/TV (r = -0.68; P = .045). Furthermore, there was a strong agreement between BV/TV derived from MRI and obtained with micro-CT (interclass correlation coefficient = 0.92; P = .001). CONCLUSIONS Bone marrow fat of small alveolar bone biopsy specimens can be quantified with sufficient spatial resolution using an ultra-high-field MRI scanner and a T1-weighted pulse sequence.

A INFLUÊNCIA DO ENSINO DA TÉCNICA RADIOGRÁFICA PERIAPICAL DO PARALELISMO PRELIMINARMENTE AO DA TÉCNICA RADIOGRÁFICA PERIAPICAL DA BISSETRIZ

The present study evaluates dental students, which are beginners in executing radiographic periapical techniques, both paralleling and bisecting-angle, according to two teaching strategies. Performance levels were found to be different according to the utilized strategy. The best results regarding the bisecting-angle technique were found when the paralleling technique was taught first.

CALCIFICAÇÃO DISTRÓFICA EM SEIO MAXILAR DE PACIENTE PEDIÁTRICO COM TRANSPLANTE HEPÁTICO E PIGMENTAÇÃO DO ÓRGÃO DENTAL

ABSTRACT Objective: To report a case of severe dystrophic calcification in maxillary sinus of a child with liver transplantation and dental organs pigmented by hyperbilirubinemia. Case description: female patient, 12 years old, with liver transplantation performed at the age of 7 due to extrahepatic biliary atresia (EHBA). The patient was receiving the immunosuppressant tacrolimus (2 mg daily). Intraoral clinical exam showed tooth green pigmentation by bilirubin. Cone-beam volumetric computed tomography (CT) was performed to verify radiographic density of pigmented dental elements. Hounsfield scale measurement did not show changes in radiographic density of dental structures. However, CT scan showed intense dystrophic calcification in the maxillary sinus region. Comments: CT scan indicated relevant radiographic findings, with radiopacity of the maxillary sinus due to fungal or non-fungal sinusitis. This case report highlights the presence of radiographic image associated with acute infectious processes that could compromise the systemic state of immunosuppressed patients.

The use of panoramic radiographs modified by an open access software to determine Mandibular Cortical Index

OBJECTIVE: to compare assessment of panoramic radiographs using Mandibular Cortical Index (MCI) by a radiologist with experience and two dentists with no experience in this index using original radiograph images and inverted images. METHODS: 64 panoramic radiographs were analyzed by three observers: a radiologist with previous experience in MCI and two trained dentists with no previous experience. First, the original images were assessed by the radiologist and defined as the gold standard. Then, dentists received training in the MCI. Assessment results obtained from the three observers were analyzed. RESULTS: When compared results from the experienced radiologist to positive and inverted images, no statistical significant difference was found. When considering the two trained observers, we found that inverted images had a lower agreement between the gold standard original images. CONCLUSION: We concluded that, within the limitations of this study, inverted radiographs are not recommended for MCI assessment.

Effect of photodynamic therapy with malachite green on non-surgical periodontal treatment in HIV patients: a pilot split-mouth study

A number of oral lesions are among the early features of HIV infection [1, 2]. It has been described that HIV patients are at risk for severe periodontal diseases [3, 4]. In addition, there is a higher prevalence of periodontal pathogens such as Actinobacillus actinomycetemcomitans (Aa), Porphyromonas gingivalis (Pg), and Tannerella forsythensis (Tf) in HIV patients compared with non-HIV patients [5, 6]. Polymerase chain reaction (PCR) is a diagnostic method that enables assessing microorganisms with very high levels of accuracy. For this reason, PCR is helpful to detect periodontal pathogens at levels below the ones detectable by cell culture or other diagnostic methods [7]. In most cases, the sole use of repeated scaling and root planing (SRP) as periodontal therapy leads to satisfactory clinical outcomes. However, the aforementioned approach may not be enough to achieve periodontal health in more challenging cases, such as residual deep pockets and furcation areas [8]. In addition, SRP often needs to be followed by adjunctive therapy such as local delivery and systemic antimicrobials and host modulation [9, 10]. One of the most recent methods used in combination with SRP in the periodontal treatment is the photodynamic therapy (PDT). In PDT, a photosensitizing agent is used to apply light therapy selectively to target specific cells. It is useful for sensitizing bacterial cells, leading to effective antimicrobial activity due to the production of cytotoxic oxygen free radicals (singlet oxygen) [11]. However, the efficacy of PDT is dependent on various factors, such as the laser wavelength and its interaction with the photosensitizer. One of the photosensitizers that have been used for the aforementioned purpose is the malachite green (MG) [12], which leads to dissipation of the cell membrane potential in both gram-positive and negative bacterial species. MG is defined as a cationic dye of the triarylmethane family that shows satisfactory absorption at the red end of the visible spectrum [13]. However, little is known on the effect of PDTwith MG as an adjunctive periodontal treatment in combination with SRP. Thus, the aim of this pilot split-mouth study was to assess clinical and microbiological effects of PDTwith MG on nonsurgical periodontal treatment in HIV patients.

Accuracy of linear measurements performed with two imaging software in cone-beam computed tomography scans of dry human mandibles

The present study aimed to assess the accuracy of linear measurements performed with two software packages in multislice (MSCT) and cone beam (CBCT) computed tomography (CT) images. The sample consisted of 10 human mandibles marked standardly 8 times with metallic orthodontic wires. The mandibles underwent both MSCT and CBCT scanning and were measured linearly and digitally with two software packages, namely Studio 3.1® (Anne Solutions®, SP, Brazil) (ST) and Implant Viewer 2.817® (Anne Solutions®, SP, Brazil) (IV). The linear measurements were the mandibular height (MH) and width (MW), and the distance from the alveolar ridge to the mandibular canal (AC). To validate the measurements, the mandibles were sectioned in the marked regions and measured with a digital caliper. Statistically significant differences were not observed between the measurements (MH, MW, and AC) taken digitally with the two software packages from images obtained from the two scanning modalities (MSCT and CBCT) and the measurements taken manually with a digital caliper (p>0.05). MSCT and CBCT images measured digitally with ST and IV software packages resulted in reliable outcomes when compared to measurements obtained manually. Both software and imaging modalities are reliably useful for planning surgical procedure in the dental practice.