Intraoral radiographs texture analysis for dental implant planning.

BACKGROUND AND OBJECTIVES: Computer vision extracts features or attributes from images improving diagnosis accuracy and aiding in clinical decisions. This study aims to investigate the feasibility of using texture analysis of periapical radiograph images as a tool for dental implant treatment planning. METHODS: Periapical radiograph images of 127 jawbone sites were obtained before and after implant placement. From the superimposition of the pre- and post-implant images, four regions of interest (ROI) were delineated on the pre-implant images for each implant site: mesial, distal and apical peri-implant areas and a central area. Each ROI was analysed using Matlab® software and seven image attributes were extracted: mean grey level (MGL), standard deviation of grey levels (SDGL), coefficient of variation (CV), entropy (En), contrast, correlation (Cor) and angular second moment (ASM). Images were grouped by bone types-Lekholm and Zarb classification (1,2,3,4). Peak insertion torque (PIT) and resonance frequency analysis (RFA) were recorded during implant placement. Differences among groups were tested for each image attribute. Agreement between measurements of the peri-implant ROIs and overall ROI (peri-implant + central area) was tested, as well as the association between primary stability measures (PIT and RFA) and texture attributes. RESULTS: Differences among bone type groups were found for MGL (p = 0.035), SDGL (p = 0.024), CV (p < 0.001) and En (p < 0.001). The apical ROI showed a significant difference from the other regions for all attributes, except Cor. Concordance correlation coefficients were all almost perfect (ρ > 0.93), except for ASM (ρ = 0.62). Texture attributes were significantly associated with the implant stability measures. CONCLUSION: Texture analysis of periapical radiographs may be a reliable non-invasive quantitative method for the assessment of jawbone and prediction of implant stability, with potential clinical applications.

The effect of marginal bone level changes on the stability of dental implants in a short-term evaluation.

OBJECTIVES: To evaluate whether changes in marginal bone level (MBL) around implants, in sites with different bone types, affect the over time implant stability measured by resonance frequency analysis (RFA). MATERIAL AND METHODS: Seventy-eight implants were inserted into jawbones of 32 patients using a two-stage surgical protocol, and implant bone sites were grouped according to the Lekholm and Zarb bone classification. The implant stability quotient (ISQ) was measured by RFA at four time points: implant placement, uncovering, rehabilitation, and at 1-year follow-up after loading. The MBL was measured on periapical radiographs at uncovering and at 1-year follow-up. Percent change in bone level was calculated based on the difference between the implant length and height from the crestal bone level to the implant apex. Descriptive statistics, Pearson's correlation, and repeated-measures ANOVA were used for data analysis. RESULTS: Significant improvement of ISQ was found between implant insertion and uncovering surgery (P < 0.001), while no significant changes were detected throughout the remaining follow-up period. The greatest improvement of ISQ was observed for bone type 4, compared with the other groups (P < 0.001). Percent change in bone level had no effect on longitudinal measures of ISQ (P = 0.337). The ISQ difference between uncovering and 1 year after loading was not correlated with percent change in bone level (r = 0.16; P = 0.157). CONCLUSION: There was increased implant stability after implant placement, but it was not affected by changes in marginal bone level during the first year of loading.

Bone quality assessment in routine dental implant treatment among Brazilian and Swedish specialists.

OBJECTIVES: To investigate the interpretation and assessment of bone quality among Brazilian and Swedish specialist performing implant treatment. MATERIAL AND METHODS: A questionnaire was developed containing open and closed questions on attitudes, knowledge, and understanding of diagnostic methods for bone quality assessment. The questionnaire was sent by mail to dental implant specialists in Brazil while the Swedish version was Web-based and sent to specialists in periodontology and maxillofacial surgery. The response rate in the Brazilian group was 15.4% and in the Swedish group 36.5%. RESULTS: Most respondents in both groups considered bone quality to be an important parameter for implant treatment outcome. Among Swedish specialists, bone quality, however, was considered to be of low relevance. The most popular method for assessing bone quality among Swedish specialists was the hand-felt perception of drilling resistance followed by radiography. The Brazilian specialists more often used peak insertion torque. Most respondents classified bone quality, and both groups used the classification proposed by Lekholm & Zarb (Tissue-Integratedprosthesis: Osseointegration in Clinical Dentistry, 1985, Quintessence, Chicago) most frequently. CONCLUSION: Specialists in both countries considered bone quality to be an important parameter for implant treatment outcome, but there was no consensus neither on what bone quality means nor on how to assess bone quality.

Low-grade central osteosarcoma of the mandible: a case study report.

Low-grade central osteosarcoma is a rare type of osteosarcoma with peculiar clinical radiographic and microscopic features. The aim of this article is to report and discuss a case of low-grade central osteosarcoma in the mandible of a 42-year-old woman. The patient reported sensing mild pain and tooth mobility for a period of 4 years, despite continuous dental treatment. Radiographic evaluation showed a mixed radiopaque/radiolucenct lesion in the body, ramus, coronoid process, and condyle of the left side of the mandible. Destruction of the mandibular cortex in the area was also observed. After incisional biopsy, the patient underwent hemimandibulectomy. Microscopic findings showed a tumor exhibiting spindle cells with nuclear hyperchromasia and no mitotic activity, irregular osteoid formation, and soft tissue infiltration. The immunohistochemical analysis of the expression of Ki-67, Cyclin B1, and PCNA proteins (cellular proliferation markers) revealed a very low Ki-67+ and Cyclin B1+ cell index (mean 7% and 3%, respectively), but a moderate number of PCNA+ cells (mean 49%). The 2 years of clinical and imaging postoperative follow-up showed no evidence of recurrence. Clinicians should be aware of these lesions, because histopathologicially low-grade central osteosarcoma may be misinterpreted as fibrous dysplasia.

Rhinolith: a radiographic finding in a dental clinic.

Rhinolith is a calcified mass found within the nasal cavity. This article is a case report of a 51-year-old woman with an unusual radiopaque lesion located in the nasal maxillary antrum cavity. It was asymptomatic and found accidentally on a routine panoramic radiograph. The rhinolith is presented along with the description of its clinical, radiographic (conventional and CT images), and histopathologic aspects. The objective of this report is to describe and discuss the differential diagnosis of the rhinolith with other oral injuries or conditions and to show how important it is for dental practitioners to be aware of their existence.

O papel da ressonância magnética no diagnóstico do adenoma pleomórfico: revisão da literatura e relato de casos / The role of magnetic resonance imaging in the diagnosis of pleomorphic adenoma: literature review and case reports

O diagnóstico precoce de lesöes como o adenoma pleomórfico (AP) de glândulas salivares pode ser limitado pela localizaçäo profunda e difusa destas glândulas nos tecidos moles da regiäo de cabeça e pescoço. Esta dificuldade agrava-se pelo fato de näo se poder estabelecer os limites de tais lesöes apenas pelo exame clínico. Das modalidades de exames por imagem, a ressonância magnética (RM) tem demonstrado papel de destaque no diagnóstico do AP por fornecer alta definiçäo dos tecidos moles, sem a utilizaçäo de radiaçäo ionizante, sendo uma das mais indicadas para esta finalidade. O objetivo deste estudo foi discutir, por meio de revisäo da literatura, a importância dos vários métodos de diagnóstico por imagem, suas vantagens e desvantagens, enfocando a utilizaçäo da RM no diagnóstico e plano de tratamento do AP de glândulas salivares. O relato de dois casos ilustra as principais justificativas para a superioridade das imagens por RM no diagnóstico da referida lesäo