Evaluation of an Electronic Periodontal Probe Versus a Manual Probe.

INTRODUCTION: Diagnosis of periodontal diseases requires reco-rding of clinical and periodontal variables. Possible measurement errors in recording the periodontal findings are dependent on the measurement method. AIM: The purpose of the trial was to investigate an electronic, pressure-calibrated probe compared with a standard, manual measurement probe used to take periodontal variables. MATERIALS AND METHODS: The study included 25 subjects suffering from periodontal disease. Their findings were taken by two users on a randomized basis using a standard probe and an electronic, pressure calibrated probe, at an interval of 24 hours. The recorded clinical variables contained Pocket Depth (PD), Attachment Level (AL), Bleeding on Probing (BOP), the complete time needed to take the findings and the sensation of pain experienced by a Visual Analogue Scale (VAS). The data were statistically analyzed using the paired t-test. RESULTS: The measurement values (24 patients) for PD (p=0.03) and BOP (p=0.01) indicated a significant difference (paired t test, p>0.05), while there was no statistical difference for AL (p=0.064). A classification of PD into groups of 1-3mm, 4-6mm and ≥7mm showed that the manual method measured higher values than the electronic method (p=0.001). The measurement values did not reveal any significant differences (p>0.05) with respect to the total time needed to take findings and the measurement time for PD/AL. There was a significant difference (Wilcoxon-test, p<0.05) in VAS values (p=0.048) and in terms of the time needed to record the findings for BOP (p=0.004). CONCLUSION: It can be assumed that the electronic probe should mainly be used in the supportive periodontal therapy. Present study showed that the use of a standard manual probe is essential to review conspicuous or unclear measurement values, or when treating deep pockets higher than 7mm.

In vitro analysis of laboratory-processed and CAD/CAM-generated occlusal onlay surfaces.

The purpose of this study was to evaluate the occlusion of all-ceramic onlay surfaces generated with a laboratory (LAB) and computer-aided design/computer-assisted manufacturing (COMP) system. The treatment of the mandibular left first molar was simulated on 16 casts. A minimum of three static contacts and their localization were defined beforehand (MIN3). The occlusal contacts obtained (CORR) were analyzed and the mean quotients (MIN3/CORR) for COMP- and LAB-processed restorations were calculated (1.06 +/- 0.17 and 1.03 +/- 0.13, respectively). The Wilcoxon signed ranks test revealed no significant differences (P <.05).

Marginal fit of heat-pressed vs. CAD/CAM processed all-ceramic onlays using a milling unit prototype.

The composite luting gap between ceramic and dental hard tissue can be termed an "Achilles heel". Therefore, one major goal of luting ceramics focuses on minimizing the inter-marginal gap area. This study evaluated the marginal accuracy of two all-ceramic systems. The null hypothesis was that there is no statistical difference between the marginal accuracy of the IPS Empress and Cerec 3D all-ceramic systems. On 16 casts, representing different clinical situations, the left first mandibular molar was prepared to receive large onlays (MOD and replacement of the distobuccal and distal cusps). For each cavity, one laboratory heat-pressed (IPS Empress) and one chairside CAD/CAM restoration (Cerec 3D) were manufactured. A newly developed milling unit was used for CAM processing. The restorations were placed in their respective cavities and die replicas were taken and examined under SEM for quantitative gap measurement. The gap width was measured at 11 defined landmarks by two different examiners. An overall gap width of 56 microm (+/- 31 microm) was measured for IPS Empress, compared to the significantly increased value of 70 pm (+/- 32 microm) for Cerec 3D. From a clinical viewpoint, the statistically significant difference between the two systems is not relevant, since both systems still exhibit a clinically acceptable gap width of less than 100 microm.