Intra-pulp temperature increase of equine cheek teeth during treatment with motorized grinding systems: influence of grinding head position and rotational speed

Abstract

BackgroundIn equine practice, teeth corrections by means of motorized grinding systems are standard procedure. The heat resulting from that treatment may cause irreparable damage to the dental pulp. It has been shown that a 5.5°C temperature rise may cause severe destruction in pulp cells. Hence, the capability to continuously form secondary dentine is lost, and may lead, due to equine-typical occlusal tooth abrasion, to an opening of the pulp cavity.To obtain reliable data on the intra-pulp increase in temperature during corrective treatments, equine cheek teeth (CT) were modified in a way (occlusal surface smoothed, apical parts detached, pulp horns standardized) that had been qualified in own former published studies. All parameters influencing the grinding process were standardized (force applied, initial temperatures, dimensions of pulp horns, positioning of grinding disk, rotational speed). During grinding experiments, imitating real dental treatments, the time span for an intra-pulp temperature increase of 5.5°C was determined.ResultsThe minimum time recorded for an intra-pulp temperature increase of 5.5°C was 38 s in mandibular CT (buccal grinding, 12,000 rpm) and 70 s in maxillary CT (flat occlusal grinding, 12,000 rpm). The data obtained showed that doubling the rotational speed of the disk results in halving the time span after which the critical intra-pulp temperature increase in maxillary CT is reached. For mandibular CT, the time span even drops by two thirds.ConclusionThe use of standardized hypsodont CT enabled comparative studies of intra-pulp heating during the grinding of occlusal tooth surfaces using different tools and techniques. The anatomical structure of the natural vital hypsodont tooth must be kept in mind, so that the findings of this study do not create a deceptive sense of security with regard to the time-dependent heating of the native pulp.

Does thermal injury affect teeth during dentistry?

“…(), and Haeussler et al . (, ) to be a threshold where pulp damage becomes likely and therefore should be avoided. Although it is reasonable to assume that pulpal tissues in mammalian species may respond in similar fashion to thermal insult, it is unclear whether anatomical differences in hypsodont teeth when compared with brachydont teeth influence the outcome of such insults in a positive or negative manner.…”

“…Haeussler et al . () suggested that thermal insults in the hypsodont tooth may be of greater significance, as the outer layer of the pulp is comprised of a single layer of odontoblasts whose responsibility is the production of secondary and tertiary (reparative) dentine in response to occlusal stimuli. Damage or disruption might lead to a decreased ability to produce dentine, thereby resulting in pulp exposure from the continued wear.…”

“…Haeussler et al . () looked at both rotational speed and head position as factors in temperature increases in maxillary and mandibular teeth. In this study the thermocouples were placed a uniform 5 mm from the occlusal surface to reduce variability in results created by individual anatomy.…”

“…() and, given the differences seen between maxillary and mandibular teeth reported by Haeussler et al . (), it is difficult to support the implementation of this when applied to small teeth with different anatomy. There were no other studies discussing thermal trauma in relation to incisors or canines.…”

“…A search for ‘equine dental heat’ resulted in further in vitro research from Haeussler et al . (). Finally, a research paper by Haeussler et al .…”