Background Dental implantation is a standard procedure for replacing missing teeth. The utilization of a cone beam computed tomography (CBCT)-assisted surgical template allows predictable flapless results, with implant placement plans performed with accuracy before the actual surgery. Aim/Hypothesis The study was conducted to evaluate the accuracy degree of computer-guided 3D planning program 3Shape for implant insertion in partially edentulous patients. Material and Methods Computer-guided implant surgery was performed in 23 patients with 57 implants in total. Preoperative CBCT scans were fused with patient's casts to produce the surgical templates. Postsurgery CBCTs were also performed after the implant placement. The collected data were used to analyze the possible differences of the implant fixture body placement between preoperative plan and postoperative actually placed implant, evaluating the angulation and distance errors. Results The mean angulation errors between the preoperative planned and postoperative placed implant was 5.84 ± 1.87 + the mean distance errors between the planned and actually placed implants were 0.67 ± 0.38 mm horizontally and 0.74 ± 0.48 mm vertically at the implant neck and 0.82 ± 0.51 mm horizontally and 0.74 ± 0.39 mm vertically at the implant apex for all 57 implants. Conclusions and Clinical Implications Computer-guided implant planning and insertion with 3Shape software, seems to provide sufficient accuracy, although more clinical studies should be conducted. Deviations are mainly related to CBCT accuracy and the implementation of the digital radiographic data to the 3D model through the software planning system.

INTRODUCTION:Foreign bodies' entrapments in the mandibular and submandibular regions are quite common.CASE PRESENTATION:We report an unusual case of foreign body (amalgam filling) entrapment over the mental foramen causing dysaesthesia in the distribution of the mental nerve. An interesting sign was blue discoloration of the overlaying oral mucosa which was interpreted as amalgam tattooing.CONCLUSION:Surgical removal of the foreign object eliminated the reported symptoms.

On the basis of computer prediction of biological activity by PASS and toxicity by DEREK, the most promising 32-alkylaminoacyl derivatives of 3-aminobenzo[d]isothiazole were selected for possible local anaesthetic action. This action was evaluated using an in vitro preparation of the isolated sciatic nerve of the rat and compared with lidocaine which was used as a reference compound. QSAR studies showed that the polarizability, polarity and molecular shape of molecules have a positive influence on their local anaesthetic activity, while contributions of aromatic CH and singly bonded nitrogen are negative. Since the estimated PASS probabilities to find local anaesthetic activity in the most active compounds are less than 50%, these compounds may be considered to be possible NCEs.

N-acetyl-L-cysteine (NAC), at a concentration of 1-60mM, has been previously used extensively for protection in a variety of cell cultures against the deleterious effects of various compounds. The results of this in vitro study show that NAC has certain unusual effects on the evoked compound action potential (CAP) of the rat sciatic nerve fibers. Firstly, at concentrations of 5.0, 3.5 and 2.5mM, concentrations used by others as a protectant for cell cultures, NAC inhibits the action potentials of the sciatic nerve fibers completely in a concentration-dependent manner within a few minutes or hours (2.5mM). Secondly, the acute inhibitory action of NAC on the CAP of the nerve fibers was not spontaneously reversible, but as soon as NAC was replaced with saline there was a partial (approximately 75%) recovery in the function of the nerve fibers. Thirdly, the no observed effect concentration for NAC was estimated to be 1mM. The paradox is that NAC at 1 mM not only had no effect on the nerve fibers, but it became an excellent neuroprotective compound, giving almost 100% neuroprotection against cadmium-induced neurotoxicity. The results show a possible effect of NAC on voltage-gated sodium and potassium channels. The observed neuroprotective-neurotoxic properties of NAC require careful reconsideration of its use in either in vitro studies or in vivo pharmaceutical applications.

The effects on nerve tissue of three dental impression pastes were compared in this study. Two of the impression pastes, Examix and Express 3M, contained vinyl polysiloxane while the other, Xanthopren, did not. An in vitro model based on the isolated sciatic nerve of the frog and rat was used. As an indication of the proper functioning of the fibres in the nerve, the amplitude of evoked compound action potential (CAP) was monitored continuously. The results clearly showed that the number of active nerve fibres in the isolated sciatic nerves of either rat or frog exposed directly to impression pastes containing vinyl polysiloxane, decreased much faster than those of the nerves in contact to impression material without vinyl polysiloxane. When the nerve of the frog was exposed to Xanthopren there was a decrease in the CAP to 50% of the control values within 56.87 ± 2.42 h (n = 6). This value was called inhibition time to 50%, IT50 and for Examix it was found to be 9.97 ± 1.53 h. When the nerve of the rat was exposed to Xanthopren, the IT50 was 15.34 ± 2.97 h (n = 6) for the Xanthopren and only 2.86 ± 1.20 h for Examix and 2.76 ± 0.48 h for Express 3M (n = 6). There was no significant difference between the action of the last two compounds (P = 0.85). This fast nerve fibre inactivation could be caused either by the chemical used for the synthesis of the two impression pastes, Examix and Express 3M, or by the unusual constriction of the nerve when it is embedded in the materials with vinyl polysiloxane. There is strong evidence to support the first case, since the incubation of the nerve in the presence of Examix, Express 3M and Xantopren in a way so the nerve was not in contact with the impression pastes, shows a much faster decrease of the CAP in the presence of the first two pastes. The decrease is caused by the death of nerve fibres, since there is no recovery in the CAP after the removal of Examix from the incubating saline.

A male patient, 65 years old presented to the clinic with generalized gingival overgrowth on the anterior mandible. The nifedipine intake, a calcium channel antagonist, caused this pathological condition. The diode laser applied on gingival tissues without injected anaesthesia. The healing was assessed and found to be uneventful. The advantages and disadvantages of this technique are discussed.