The aim of this review is to offer dentists a summary of the recent and important progress being made in the neurophysiological and psychological bases of orofacial pain. In this paper, 1) the function of nociceptive primary neurons with special reference to the polymodal receptor, 2) long-lasting effects of the neuropeptides released from the central terminals of nociceptive afferents on the dorsal horn or trigeminal caudal neurons, 3) the ascending nociceptive tracts : the spinothalamic and spinoreticular tract, 4) descending pain-control systems, 5) the central mechanism of chronic pain, are briefly reviewed. The author hopes that this guidebook of the recent neurophysiological research will result in progress of clinical pain control in dentistry and help readers develop a better understanding of pain mechanisms.
There is a potential risk of cross contamination in a dental clinic through air turbine handpiece system, since regular air turbine handpiece produce a small amout of air "suckback" whenever rotation of a handpiece stops. Perfect sterilization of a handpiece and a connected hose which may contain debris including bacteria and viruses, is necessary but neither easy nor being done routinely.
This study was performed to evaluate the effectivness of an anti cross contamination device (AIR MEDICATM) for dental handpiece by using three bacterial strains. It was found that the use of AIR MEDICA efficiently reduces the contamintion level inside the handpiece and hoses to less than 0.04%.
The commercialized model of the division method electronic root canal length measuring device, which simultaneously measures two impedances of a canal at two frequencies and computes the quotient of two impedance values, has been developed.
The characteristics of this device were as follows :
1. The meter value of the device was hardly affected by the electric conditions of the canal, but it considerably changed near apical constriction.
2. The relationship between the meter value and the location of the file tip in the canal became more linear by the correction of the quotient using the conversion table on the microcomputer of the the device.
3. Without any adjustment of the device, an accurate electronic measurement of the root canal length was performed by the device.
In order to carry out an ideal root canal treatment there are some principles concerning with the endodontic procedures. Among them, the hermetic cavity sealing of root canals can be mentioned. Of course, a lot of researches have been conducted for the purpose of producing the ideal cavity sealing materials. But, there were always some disadvantages.
This time, in order to improve the disadvantages such as smell, taste and irritation, a new caviy sealing material for a root canal treatment was developed in cooperation with Showa Yakuhin Co. and was named Canseal.
Based upon the basic and experimental animimal researches, we carried out its clinical application by using 10 incisor and 40 molar teeth of 41 patients.
As a result, clinical problems such as the falling off, wear and fracture were minor. In addition, the smell and taste were also greatly improved and did not produced a unpleasant sensation like the zinc oxide eugenol cement. The mixing procedure was no difference in comparision with the zinc oxide eugenol cement.
From the above results, it can be concluded that this newly developed non-eugenol cavity sealing material Canseal does not have any serious clinical problems and that this material can be used for the rutine endodontic treatment.
A 12-yrs-old man came to our office to complaining of severe pain in the periapical area of upper left second incisor. Although no carious lesion was found, a large radiolucent image was clarified at its corresponding area by a x-ray examination. Since an anaerobic infection was suspected, Taribid eye drop was used as an intracanal irrigant and a disinfectant. The Tarivid containing 3% Ofloxacin shows strong antibacterial effect on anaerobes.
Intracanal exudate was collected at the first visit and was sent to a commercial laboratory, and several examinations were performed there. They reported as follows : 1. Gram-negative rod (+), anaerobic culture (+), microorganisms were identified as Bacteroides Sp. 2. Sensitivity test was negative only in the case of AMPC.
Besides these examinations, anaerobic culture using Pradia anaerobic culture kit (Showa) was performed, and smear preparation of the canal fluid was stained to examine microorganisms and inflammatory cells, by ourselves at each visit.
Succesful repair of the periapical bone was confirmed by a 2-yr-postoperative x-ray examination.
To avoid cross contaminations or infections during dental treatments such as extractions, incisions, and periodontic treatments, aseptic treatments, necessary are although they are not possible at all.
But for endodontics, we use a lot of instruments, rubber dum, endodontic meters, irrigator, etc., and their good sterilization and disinfection enable to make a perfect aseptic treatment.
The following study describe a method of sterilization and disinfection of endodontic instruments and a root canal filling technique of the Obturation System.