A study of digital sampling in gnathosonics

Abstract

The purpose of this study has been to provide clinicians with a simple low cost system for gnathosonic investigation in the dental surgery, instead of referring patients to specialist centres. Hitherto the literature describing the sounds made by occlusion of the teeth has offered many conflicting hypotheses as to the relationship between the sounds produced and the condition of the gnathic system. Many techniques developed to investigate factors involved in tooth vibration or impact are cumbersome and time consuming. The simple system developed in this work is based on fast digital capture using an inexpensive microcomputer of a type commonly found in the home. Specific software has been developed to capture and manipulate the transient signals generated by tooth and other impacts. As part of the study the software has been rigorously verified for timings, frequency limits and program errors, and has been validated using both mathematically generated and other control signals such as those provided by a signal generator. The system has been used both in vitro and in vivo to investigate the manner in which shock waves from tooth impacts are received after transmission through the body structures. A meaningful interpretation of the data recorded has been established, although it has had to be accepted that scientific analysis of shock wave propagation through tissue requires further investigation and is beyond the scope of this work. In addition to sounds generated by occlusion of the teeth, sounds made by the percussion of implants set into the maxilla and mandible have also been recorded, on the assumption that serial recordings taken from the time of insertion could indicate integration or give early warning of failure. The technique of digital signal capture has been applied elsewhere in the body, for example sounds made by both natural and artificial joints. This limited study indicates that the developed system may have much wider application than gnathosonic measurement alone. It is suggested that the differing results of many researchers into gnathosonics may be due to lack of standardisation of the sensors and other equipment employed, and to misinterpretation of the sound recordings of the occlusion of the teeth. It is proposed that certain parameters should be established in the field of gnathosonics, particularly in regard to the sensors and recording apparatus. It is only then that the results from serial sessions, and the work of different investigators will stand comparison.