Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, UK.
Equine Vet J. 2013 May;45(3):355-60. doi: 10.1111/j.2042-3306.2012.00650.x. Epub 2012 Sep 26.
Although equine motorised dental instruments are widely used, there is limited information on their thermal effect on teeth. The recently described variation in subocclusal secondary dentine depth overlying individual pulp horns may affect heat transmission to the underlying pulps.
This study compared the effect of 3 different equine motorised dental instruments on the pulpar temperature of equine cheek teeth with and without the use of water cooling. It also evaluated the effect of subocclusal secondary dentine thickness on pulpar temperature changes.
A thermocouple probe was inserted into the pulp horns of 188 transversely sectioned maxillary cheek teeth with its tip lying subocclusally. Pulpar temperature changes were recorded during and following the continuous use of 3 different equine motorised dental instruments (A, B and C) for sequential time periods, with and without the use of water cooling.
Using motorised dental instrument B compared with either A or C increased the likelihood that the critical temperature was reached in pulps by 8.6 times. Compared with rasping for 30 s, rasping for 45, 60 and 90 s increased the likelihood that the critical temperature would be reached in pulps by 7.3, 8.9 and 24.7 times, respectively. Thicker subocclusal secondary dentine (odds ratio [OR] = 0.75/mm) and water cooling (OR = 0.14) were both protective against the likelihood of the pulp reaching the critical temperature.
Prolonged rasping with motorised dental instruments increased the likelihood that a pulp would be heated above the critical temperature. Increased dentinal thickness and water cooling had protective roles in reducing pulpar heating.
Motorised dental instruments have the potential to seriously damage equine pulp if used inappropriately. Higher speed motorised dental instruments should be used for less time and teeth should be water cooled during or immediately after instrument use to reduce the risk of thermal pulpar damage.
尽管马用机动牙科器械已广泛应用，但有关其对牙齿热效应的信息有限。最近描述的个体牙髓角上方近远中向继发性牙本质深度的变化可能会影响热向下方牙髓的传递。
本研究比较了 3 种不同马用机动牙科器械在使用和不使用水冷却的情况下对马颊牙牙髓温度的影响，并评估了近远中向继发性牙本质厚度对牙髓温度变化的影响。
将热电偶探头插入 188 个横向截断的上颌颊牙的牙髓角，其尖端位于近远中面。在连续使用 3 种不同的马用机动牙科器械（A、B 和 C）进行连续时间测量期间和之后，记录牙髓温度变化，同时使用和不使用水冷却。
与 A 或 C 相比，使用牙科器械 B 使牙髓达到临界温度的可能性增加了 8.6 倍。与 30s 锉牙相比，锉牙 45s、60s 和 90s 使牙髓达到临界温度的可能性分别增加了 7.3、8.9 和 24.7 倍。较厚的近远中向继发性牙本质（比值比[OR] = 0.75/mm）和水冷却（OR = 0.14）均对牙髓达到临界温度的可能性有保护作用。
长时间使用机动牙科器械锉牙会增加牙髓被加热到临界温度以上的可能性。增加牙本质厚度和使用水冷却在减少牙髓加热方面具有保护作用。
如果使用不当，机动牙科器械有可能严重损害马的牙髓。在使用更高转速的机动牙科器械时，应减少使用时间，并在器械使用期间或使用后立即对牙齿进行冷却，以降低热牙髓损伤的风险。
