Estimation of single-root surface area from true thickness data and from thickness derived from digital dental radiography.

OBJECTIVES: The prognosis of a tooth affected by periodontitis may depend on the amount of bone remaining around the root surface. The aim of this study was to find how the surface area of a single root is related to the true thickness data and the calculated thickness data from digital dental radiographs. METHODS: Eight extracted single-root teeth were digitized three-dimensionally for direct surface area measurement. Meanwhile, they were also exposed to a digital dental X-ray system. The true thickness of the tooth root was measured. The estimated circumference data were calculated from both the measured thickness and the thickness estimated from the digital image and then measured and estimated circumferences were compared. RESULTS: (1) The largest circumference difference mean for measured thickness and for estimated thickness was -4.94% (+/-0.07%) and 23.02% (+/-1.12%) respectively. (2) The largest 95% confidence interval for difference means for measured thickness and for estimated thickness was (-2.82%, -1.87%) and (-5.42%, 2.22%), respectively. CONCLUSIONS: When the thickness data are available, the surface area of a single-root tooth can be estimated to an error of less than 5%. Theoretically, the root thickness can be derived from the projected radiological image of the tooth. However, the error of estimated circumference from digital dental radiography may be over 20%. This error can be minimized if the estimated thickness from digital dental radiography can be made more accurate.

Role of laparoscopic cholecystectomy in the management of polypoid lesions of the gallbladder.

This retrospective clinicohistopathologic study was performed to delineate the role of laparoscopic cholecystectomy in the management of polypoid lesions of the gallbladder. One hundred forty-three consecutive patients who had a preoperative sonographic diagnosis of polypoid lesions of the gallbladder with a diameter less than 1.5 cm and who underwent laparoscopic cholecystectomy at Cathay General Hospital were included in the analysis. Histopathologic study showed that 22 (15.4%) patients had true tumors, including adenoma (16), adenoma with focal adenocarcinoma (2), adenocarcinoma (3), and carcinoid tumor (1). Tumorlike lesions were found in 121 (84.6%) patients and included cholesterol polyp (106), adenomyomatous hyperplasia (10), inflammatory polyp (3), and papillary hyperplasia (2). The mean diameter of malignant polypoid lesions of the gallbladder was 1.35 +/- 0.42 cm, which was significantly larger than that of cholesterol polyps (0.66 +/- 0.40 cm, P = 0.0001) but not significantly larger than that of adenomyomatous hyperplasias (1.12 +/- 0.42 cm) and adenomas (1.08 +/- 0.47 cm). The mean age of patients with malignant polypoid lesions of the gallbladder (61.2 +/- 13.3 years old) was significantly older than that of patients with adenomyomatous hyperplasia (46.6 +/- 13.4 years, P = 0.03), cholesterol polyps (44.5 +/- 10.5 years, P = 0.0003), and adenomas (41.4 +/- 9.4 years, P = 0.0008). Clinical follow-up showed that most (98.6%) patients benefited from the minimal invasiveness of laparoscopic cholecystectomy with satisfactory surgical results. We conclude that laparoscopic cholecystectomy is a reliable, safe, and minimally invasive biopsy procedure and definite management of polypoid lesions of the gallbladder with a diameter less than 1.5 cm.

Acoustic and intelligibility characteristics of sentence production in neurogenic speech disorders.

The purpose of this study was to examine the relationship between scaled speech intelligibility and selected acoustic variables in persons with dysarthria. Control speakers and speakers with amyotrophic lateral sclerosis (ALS) and Parkinson's disease (PD) produced sentences which were analyzed acoustically and perceptually. The acoustic variables included total utterance durations, segment durations, estimates of the acoustic vowel space, and slopes of formant transitions; the perceptual variables included scaled speech intelligibility and severity of speech involvement. Results indicated that the temporal variables typically differentiated the ALS group, but not the PD group, from the controls, and that vowel spaces were smaller for both neurogenic groups as compared to controls, but only significantly so for the ALS speakers. The relation of these acoustic measures to scaled speech intelligibility is shown to be complex, and the composite results are discussed in terms of sentence vs. single-word intelligibility estimates and their underlying acoustic bases.

Effect of speaking rate manipulations on acoustic and perceptual aspects of the dysarthria in amyotrophic lateral sclerosis.

The current study explored the acoustic and perceptual effects of speaking rate adjustments in persons with amyotrophic lateral sclerosis (ALS) and in neurologically normal individuals. Sentence utterances were obtained from the participants at two self-selected speaking rates: habitual and fast. Total utterance durations, segment durations, and vowel formant frequencies comprised the acoustic measures, whereas magnitude estimates of speech intelligibility and severity of speech involvement were the perceptual measures. Results showed that participants in both the neurologically normal and ALS groups were able to increase their speaking rate when asked to do so, but that the participants with ALS were significantly slower than the neurologically normal participants at both rates. Both groups of participants also showed compression of the acoustic vowel space with increased speaking rate, with the vowel spaces of participants with ALS generally being more compressed than the vowel spaces of neurologically normal participants, at either rate. Most importantly, the perceptual measures failed to show any effect of the speaking rate adjustment on scaled intelligibility or severity, for either group. These findings are discussed relative to the general issue of slow habitual speaking rates among many speakers with dysarthria, and possible explanations for the slowness. The lack of an effect of increased rate on the perception of the speech deficit among speakers with ALS argues against the idea that the habitually slow rates are a form of compensation to reduce the complexity of speech production.

Adenocarcinoma of the gastric cardia: prognostic significance of pathologic and treatment factors.

The records of 146 patients who had surgery for adenocarcinoma of the gastric cardia between 1977 and 1992 at National Taiwan University Hospital were retrospectively analyzed. The prognostic significance of pathologic and surgical treatment factors was examined by log rank test and stepwise regression procedures. The overall 2-year and 5-year survival rates were 40.2% and 23.7%, respectively. The pathologic factors analyzed included: age, sex, tumor diameter, esophageal invasion, pathologic grading, vascular invasion, perineural invasion, depth of invasion, node-status, distant metastasis and number of positive lymph nodes. The surgical treatment factors analyzed included:surgical procedure, region of lymphadenectomy, resection margin and resection status. Resection status was classified into three categories: absolute curative, relative curative and palliative. Univariate analyses showed that esophageal invasion, vascular invasion, depth of invasion, node status, node number, resection margin and resection status were significant prognostic factors. The selected stepwise regression model identified three significant independent factors: node status, resection status and esophageal invasion. Aggressive surgical management, including combined resection and extended lymphadenectomy, may be helpful for patients with adenocarcinoma of the gastric cardia.