Two-point discrimination values vary depending on test site, sex and test modality in the orofacial region: a preliminary study

Abstract The two-point discrimination (TPD) test is one of the most commonly used neurosensory tests to assess mechanoperception in the clinical settings. While there have been numerous studies of functional sensibility of the hand using TPD test, there have been relatively not enough reports on TPD in the orofacial region. Objective The aims of the present study were to determine the normal values of TPD in the six trigeminal sites (the forehead, cheek, mentum, upper lip, lower lip, and the tongue tip) and to investigate the effect of the site, sex, and test modality on the TPD perception. Material and Methods Forty healthy volunteers consisting of age-matched men (20) and women (20) with a mean age of 27.1 years were recruited. One examiner performed the TPD test using a simple hand-operated device, i.e., by drawing compass with a blunt or sharp-pointed tip. The static TPD with a blunt-pointed tip (STPDB), moving TPD with a blunt-pointed tip (MTPDB), and static TPD with a sharp-pointed tip (STPDS) were measured. The predictors were the site, sex, and test modality, and the outcome variable was the TPD value. Three-way ANOVA was used for statistics. Results The analysis showed a significant effect of the site, sex and test modality on the TPD values. Significant differences between the test sites were observed with the descending order from the forehead and cheek>mentum>upper lip and lower lip>tongue tip and index finger. Women showed lower TPD values than those of men. The STPDS measurements were consistently lower than those of the STPDB and MTPDB. Conclusions The normal values of TPD in this study suggest that the cheek and forehead were less sensitive than other regions evaluated and women were more sensitive than men. The STPDS was the most sensitive test modality.

Oseopercepción: una puesta al día / Osseoperception: an update

La incorporación de implantes dentales al Sistema Estomatognático genera muchos cuestionamientos, entre ellos: ¿Cómo se explica que el paciente “sienta” a través de estos sistemas de anclaje?; ¿Por qué el paciente dice que mastica mejor que con las prótesis mucosoportadas?;¿Por qué a pesar de haber perdido dos componentes fisiológicos esenciales (dientes y periodonto) no se aprecian clínicamente importantes problemas dentro del sistema?; ¿Qué reordenamientos del sistema nervioso determinan la regulación motora luego de rehabilitado con estas técnicas? Es probable que las respuestas surjan a través del conocimiento de una nueva modalidad sensorial descriptacomo oseopercepción, la cual implica un reordenamiento de las áreas sensitivas y motoras de la corteza cerebral (neuroplasticidad).

Many questions arise from the introduction of dental implants into the stomatognathic system, for example: How can patients “feel” through these anchorage structures? Why does the patient feel that his mastication is improved with respect to the classic complete dentures? Why there are not remarkable alterations in the function of the stomatognathic system despite the loss of two essential componentsof this system? What rearrangements of the nervous system take place after the placement of dental implants that control the motor regulation of the stomatognathic system? Probably, the answer to these questions may come from the study of a new sensorymodality known as osseoperception, which involves a rearrangement of sensory and motor areas of the brain cortex (neuroplasticity).

Study of descendent course of buccal nerve in adults individuals / Estudio del trayecto descendente del nervio bucal en individuos adultos

The knowledge of the buccal nerve anatomy is of fundamental importance not only for the anesthesia but also for a safe intervention in the retromolar area. The aim of this work was to study its trajectory, in the area where it is related to the anterior margin of the ramus of the mandible, therefore providing important data for a safe intervention in the region. In this study we used 10 hemi-heads from male and female adults, from different ethnic groups. They were fixed in formol, and belong to the Anatomy Laboratory at the Faculty of Dentistry in Araraquara UNESP. These hemi-heads were dissected by lateral access, preserving the buccal nerve in its trajectory related to the anterior margin of the ramus of the mandible until its penetration in the buccinator muscle. Next, we desinserted the masseter muscle so that all the ramus of the mandible were exposed. Then, the following measurements were carried out: from the base of the mandible until the buccal nerve and from the base of the mandible until the apices of the mandibular coronoid process. These measurements were accomplished with a Mitutoyo CD-6'' CS digital paquimeter. The following average values were obtained: 32.26 mm (to the left side) and 32.04 mm (to the right side), from the base of the mandible until the buccal nerve and 59.09 mm (to the left side) and 58.95 mm (to the right side) from the base of the mandible until the apices of the coronoid process. We have concluded that normally, the buccal nerve crosses the anterior margin of the ramus of the mandible in an area which is above the superior half of the ramus of the mandible and also that the interventions in the retromolar region do not offer great risks of injury in the buccal nerve.

El conocimiento de la anatomía del nervio bucal es de importancia fundamental no sólo para la anestesia, sino también para una intervención segura en la zona retromolar. El objetivo de este trabajo fue estudiar la trayectoria del nervio bucal, en la zona en que se relaciona con el margen anterior de la rama de la mandíbula, proporcionando datos importantes para una intervención segura en la región. En este estudio fueron utilizadas 10 hemi-cabezas de hombres y mujeres adultos, de diferentes grupos étnicos. Las cabezas fueron fijadas en formol, y pertenecen al Laboratorio de Anatomía de la Facultad de Odontología de Araraquara UNESP. Las hemi-cabezas fueron disecadas por medio de un acceso lateral, preservando al nervio bucal en su trayectoria en relación con el margen anterior de la rama de la mandíbula hasta su penetración en el músculo buccinador. A continuación, el músculo masetero fue desinsertado de modo que toda la rama de la mandíbula fue expuesta. A continuación, se llevaron a cabo las siguientes mediciones: desde la base de la mandíbula hasta el nervio bucal y de la base de la mandíbula hasta los ápices de los procesos coronoides mandibular. Estas mediciones se realizaron con un caliper digital CD-6'' CS Mitutoyo. Los siguientes valores promedio fueron obtenidos: 32,26 mm (a la izquierda) y 32,04 mm (a la derecha) de la base de la mandíbula hasta el nervio bucal y 59,09 mm (a la izquierda) y 58,95 mm (a la derecha) de la base de la mandíbula hasta los ápices de los procesos coronoides. En conclusión, normalmente, el nervio bucal cruza el margen anterior de la rama de la mandíbula en una zona que está por encima de la media superior de la rama de la mandíbula, y también que las intervenciones en la región retromolar no ofrecen grandes riesgos de lesiones en el nervio bucal.