Оцінка безпечності видалення залишків фіксаційного цементу після процедури дебондингу непрямих реставрацій фронтальної групи зубів

Abstract

В даній статті представлено результати температурних показників всередині пульпової камери при видаленні залишків фіксаційного цементу з твердих тканин експериментальних зубів після дебондингу непрямих реставрацій фронтальної групи зубів, згідно яких можна стверджувати про перевагу твердотільних лазерів, використання яких забезпечує безпечність проведення процедури та не призводить до перевищення критичного порогу нагріву пульпи.

В данной статье представлены результаты температурных показателей внутри пульповой камеры при удалении остатков фиксационного цемента с твердых тканей экспериментальных зубов после дебондинга непрямых реставраций фронтальной группы зубов, согласно которых можно утверждать о преимуществе использования лазерной энергии, которая обеспечивает безопасность данной процедуры и не приводит к превышению критического порога нагрева пульпы.

In recent years, the use of veneers in prosthetic dentistry has substantially grown, largely as a result of not only scientific achievements in technology of their manufacturing, but also an increased interest of patients. It is because tooth preparation for a veneer is practically noninvasive, i.e. the most of the tooth tissues is kept in comparison with preparation for a crown. However, even such high-precision restorations have a failure rate and complications. The least common problems associated with porcelain laminate veneers are marginal discoloration, caries and loss of color stability. Removal of the scraps of cement for fixation after veneers debonding is generally performed with a rotary instrument. Using this method the scraps of cement for fixation removal is complete, but is relatively time consuming and this technique is not ideal as the underlying tooth structure may be damaged. Also the rotary instruments can generate heat and increase pulpul temperature above the critical 5,50С. Temperature increases in dental and pulp tissues can promote undesirable thermal damage. It has been shown that a temperature rise in the pulp chamber of 5.5°C for 1 min produced irreversible pulpal damage. With the recent introduction of lasers in dentistry, there may be beneficial application in removing scraps of cement for fixation with lasers. Debonding mechanisms that enable the adhesive resin to degrade by laser energy was explained by Tocchio et al. as thermal softening, thermal ablation, or photoablation. The methacrylate is a target chromophore in procedure of scraps removal. Overall, this method of removing the scraps of cement for fixation from tooth surface using Er-YAG and Er, Cr: YSGG laser is an effective clinical way. Further studies are necessary to investigate the thermal effects of this method on the pulpal tissues. Purpose. The aim of our study was to investigate the safety removal of the scraps of cement for fixation after debonding of ceramic restorations by comparing the dynamics of thermometric indicators. Object and methods. Experimental studies conducted at Shupyk National Medical Academy of postgraduate education. According to our study following groups were created: group 1 (control) – scraps removal using rotary instruments (24 teeth), group II – scraps removal using a solid-state laser (Er: YAG) (32 teeth), group III – scraps removal using a solid-state laser (Er, Cr: YSGG) (34 teeth). The intrapulpal temperature measurements perform with thermocouple. Results of the study. According to the results of our study using an Er:YAG and Er, Cr: YSGG lasers allows to remove the scraps of cement for fixation from teeth without aggressive destruction of underlying tooth structure. Both laser groups generated significantly less heat compared to bur group (p<0,05). None of the laser groups increased pulpul axial wall heat temperature above the critical 5,50С (3,30С for Er:YAG and 2,2 for Er,Cr:YSGG lasers). The bur group generated higher heat (more than 5,50С). According to the results of our experimental study on thermal safety Er:YAG and Er, Cr:YSGG lasers allow to remove the scraps of cement for fixation from teeth below the critical threshold described of 5,50С (Zach and Cohen).