Digital subtraction radiography evaluation of longitudinal bone density changes around immediate loading implants: a pilot study.

OBJECTIVE: The aim of this study was to assess longitudinal quantitative changes in bone density around different implant loading protocols and implant surfaces measured by digital subtraction radiography (DSR). METHODS: 12 patients received bilateral homologous standard and TiUnite® (Nobel Biocare, Kloten, Switzerland) single-tooth implants under 2 implant-loading protocols: immediate loading (8 patients, 16 implants, 12 maxillary) and conventional loading (4 patients, 8 implants, 4 maxillary). Standardized periapical radiographs were taken immediately after implant placement (baseline image) and at the 3-month, 6-month and 12-month follow ups. Radiographic images were digitized and submitted to digital subtraction using the DSR system® (Electro Medical System, Nyon, Switzerland), resulting in three subtracted images. Quantitative analysis of bone density was performed using Image Tool® software (University of Texas Health Science Centre, San Antonio, TX) to assess pixel value changes in five areas around the implants (crestal, subcrestal, medial third, apical-lateral and apical). RESULTS: Repeated-measures analysis of variance showed that grey levels were significantly influenced by follow-up time and implant-loading protocol. A linear increase in grey levels was found for immediate loading (IML) implants and a significant decrease in grey levels was observed in the 12-month follow up for conventional loading implants. No effect of implant surface treatment was observed. CONCLUSION: In conclusion, IML protocol induced mineral bone gain around single-tooth implants after the first year under function for cases with favourable bone conditions.

Digital subtraction radiography evaluation of the bone repair process of chronic apical periodontitis after root canal treatment.

AIM: To monitor radiographically the progress of bone repair within chronic periapical lesions after root canal treatment using digital subtraction radiography (DSR). METHODOLOGY: Twelve patients with 17 single-rooted teeth with chronic apical periodontitis associated with an infected necrotic pulp were selected for root canal treatment. Periapical radiographs were taken before treatment (baseline) and immediately post-treatment, 45, 90, 135 and 180 days after treatment. The radiographic protocol included the use of individualized film holders with silicone bite blocks. The six radiographic images were digitized and submitted to digital subtraction using DSR software, resulting in five subtracted images (SI). Quantitative analysis of these SI was performed using Image Tool software to assess pixel value changes, considering a step-wedge as the gold standard and a cut-off value of 128 pixels. The aim was to identify any increase or decrease in mineral density in the region of the periapical lesion. RESULTS: A minor decrease in mineral density at the canal filling session and a significant progressive mineral gain in the following evaluations (P < 0.001) occurred. Pairwise comparison of pixel grey values revealed that only the 180-day follow-up differed significantly from the previous SI. CONCLUSION: Digital subtraction radiography is a useful method for evaluating the progress of bone repair after root canal treatment. Noticeable mineral gain was observed approximately 90 days after root canal filling and definite bone repair after 180 days.

Differential infiltration of CD8+ and NK cells in lip and oral cavity squamous cell carcinoma.

BACKGROUND: CD8+ and natural killer (NK) cells have been considered the most effective cells in the combat of cancer, contributing to better prognosis and longer survival. METHODS: The aim of this study was to evaluate the population of CD8+ and NK cells, by immunohistochemistry, in samples of oral cavity squamous cell carcinoma (OCSCC) and lip squamous cell carcinoma (LSCC), leukoplakia, actinic cheilitis, and healthy oral mucosa (control). The relationship of CD8+ and NK cells with survival data, lymph node metastasis, tumor size, and proliferative index was also evaluated. RESULTS: The number of peritumoral and intratumoral CD8+ and NK cells was significantly higher in LSCC, when compared with control, pre-malignant lesions, and OCSCC. A higher proportion of peritumoral CD8+ cells demonstrated correlation with a lower neoplastic proliferative index. Moreover, patients with OCSCC with a high density of peritumoral CD8+ cells showed a tendency towards a longer survival time. CONCLUSIONS: The differential CD8+ and NK cells infiltration in oral SCC might reflect a distinctive tumor microenvironment with a favorable local cytotoxic immune response against neoplastic cells.

In vivo study of pixel grey-measurement in digital subtraction radiography for monitoring caries remineralization.

OBJECTIVES: The aim of this study was to evaluate the performance of a quantitative method, based on pixel grey value measurements, for monitoring caries remineralization. METHODS: Proximal radiographs of 11 patients (61 enamel caries lesions) were taken both before and after a 2 month remineralization protocol. Radiographs were digitized and for each area a follow-up image was subtracted from a baseline image. A quantitative analysis was undertaken using ImageTool software (University of Texas Health Science Center, San Antonio, TX). For each caries lesion diagnosed, a mean pixel value was obtained in digital subtraction radiographs (SR) using a scale ranging from 0-255 grey values. To identify caries status after the remineralization protocol, a subjective analysis of SR was undertaken by 6 radiologists who graded the lesions as demineralized (n = 10), unchanged (n = 34) or remineralized (n = 17). RESULTS: There was a statistically significant difference between the mean pixel values for demineralized (112.1+/-14.4), unchanged (127.3+/-12.3) and remineralized (137.5+/-13.8) lesions. CONCLUSIONS: It was concluded that the status of proximal caries lesions after remineralization therapy can be assessed by pixel grey measurements in SR and may constitute a suitable complementary method for monitoring the results of remineralization protocol in clinical practice.

Persistent apical periodontitis associated with a calcifying odontogenic cyst.

AIM: To report a case of calcifying odontogenic cyst (COC) that was suggestive of apical periodontitis adjacent to the roots of the maxillary incisor teeth. SUMMARY: Tooth 21 presented with clinical and radiographic signs of secondary infection, a post within the root canal and substantial internal tooth destruction; it was scheduled for endodontic surgery. Teeth 12 and 22 were root filled following the placement of a calcium hydroxide intracanal dressing for 21 days. Three attempts at root canal disinfection in tooth 11 were unsuccessful, and a persistent purulent drainage precluded completion of root canal treatment. Surgical enucleation of the periapical lesion was undertaken and the tissues submitted for histopathological examination. A diagnosis of COC was established based on the microscopic analysis. COC is an unusual benign lesion that represents 2% of all odontogenic lesions. Depending on the stage of development, it can mimic a large lesion associated with apical periodontitis and should therefore be considered in the differential diagnosis. In the case of COC, the definitive diagnosis can only be made with histopathological analysis. KEY LEARNING POINTS: Persistent apical periodontitis may be of nonendodontic origin. * Histological examination is essential to establish the cause of persistent apical periodontitis. * Calcifying odontogenic cyst can mimic apical periodontitis.

Unicystic ameloblastoma in a child: a differential diagnosis from the dentigerous cyst and the inflammatory follicular cyst.

Unicystic ameloblastoma (UA) is a benign epithelial odontogenic tumor of the jaws with an aggressive potential that commonly occurs in children. This cystic odontogenic neoplasm is generally asymptomatic and found during routine radiographs. The purposes of this report were to describe a case of UA involving the crown of the unerupted right mandibular second premolar in an 11-year-old girl under orthodontic treatment, and discuss its diagnosis and radiographic and microscopic findings, emphasizing its distinction from the dentigerous cyst and the inflammatory follicular cyst.

Lichen sclerosus et atrophicus of the oral mucosa.

Lichen sclerosus et atrophicus (LSA) is a chronic, benign, depigmenting disease of the skin and mucous membranes most frequently affecting the female genitalia. Involvement of the oral mucosa without concurrent genital or skin lesions has been reported only occasionally in the literature. In view of the rarity of reported cases, one lesion affecting only the labial mucocutaneous area is presented along with a description of the disease's clinical and histopathological findings.

[Reliability of the declaration of underlying cause of infant deaths in the metropolitan region of southeastern Brazil]. / Confiabilidade da declaração de causa básica de mortes infantis em região metropolitana do sudeste do Brasil.

The quality of official information on underlying causes of infant deaths was studied on the basis of data collected for a population-based study of the surveillance of infant mortality in the metropolitan region of Belo Horizonte, Brazil in 1989. The survey included the analysis of a sample of infant deaths carried out by comparing the underlying causes of death as coded on death certificates to those recorded by a group of doctors who abstracted information from hospital records. We verified that 11.7% of neonatal deaths did not have the underlying cause of death confirmed by the investigation (kappa = 0.61), and neither did 44.0% of post-neonatal deaths (kappa = 0.47). It is believed that this major disagreement among post-neonatal deaths is due to the close correlation observed among the major causes of death within this group (pneumonia, diarrhoea and malnutrition). For example, associated malnutrition was observed in 76.9% of those cases in which diarrhoea was coded as the underlying cause of death. It was concluded that the quality of the death certificates is not satisfactory. However, the composition of the main groups of causes presented no significant alteration after investigation and may be used in public health surveillance, especially if we regard pneumonia, diarrhoea and malnutrition as a group with the same determinants. Unfortunately, this group still accounts for a great number of otherwise avoidable deaths in Brazil.