Morphological and Functional Parameters in Patients with Tooth Wear before and after Treatment

Abstract

Advanced tooth wear often results in lost vertical dimension and impacts facial aesthetics. Complex restorative treatment can replace the lost tooth structure and improve functional occlusal and facial skeleton parameters.

Purpose: The aim of the study is to assess changes in the morphological and functional occlusal parameters of the facial skeleton after prosthetic rehabilitation that increased lost occlusal vertical dimension.

Material and methodology: 50 patients with advanced tooth wear were clinically examined, to assess the degree of wear. Each subject underwent cephalometric analysis, digital occlusal analysis, and electromyographic analysis, of the anterior temporalis, superficial masetter, anterior digastric, and the sternocleidomastoid muscles. Prosthodontic treatment was performed to restore the occlusal vertical dimension of each subject's occlusion, which was followed by repeating the pretreatment analyses. Pre and post treatment parameters were statistically compared.

Results: Pre-treatment cephalometric analysis showed that lost vertical dimension reduced anterior facial height and resulted in small angular skeletal parameters. Post treatment anterior facial height increased from the increased occlusal vertical dimension. The mean value of functional electrical activity during clenching post treatment, increased compared to pretreatment.

Conclusion: Increasing the vertical dimension of occlusion improved facial aesthetics by positively affecting facial skeletal angles. The restored occlusal surface morphology changed the pre treatment flat broad occlusal contacts into more point contacts. The increased vertical dimension of occlusion after treatment also increased muscle activity levels over the pretreatment levels after three months period of adaptation.

Keywords: Cephalometric analysis; EMG; T-Scan.; occlusal vertical dimension; rehabilitation; tooth wear.

Fig. (1). Reference points with regard to the cephalometric analysis according to Ricketts and McNamara.

Soft tissue cephalometric landmarks G’ (Glabella) – the most anterior soft tissue point of the frontal bone, Sn’ – the point at which the nasal septum merges mesially with the upper cutaneous lip in the mid-sagittal plane Me’ (Soft tissue Menton) – the point on the lower contour of the chin opposite to the hard tissue Menton Skeletal / hard tissue cephalometric landmarks A (Subspinale) - the deepest point in the midsagittal plane between the anterior nasal spine and prosthion, Pr (Prosthion) - the point of the upper alveolar process that projects most anteriorly in the midline, ANS (Anterior nasal spine) - the anterior point of the nasal floor, B (Sm) (Supramentale) - the deepest point in the midsagittal plane between infradentale and Pg, Ir (Infradentale) - the most anterior point of the alveolar process of the mandible, Co (Condylion) - the most superior posterior point on the outline of the mandibular condyle, Gn (Gnathion) - most anterior and lowest point of the symphysis, Me (Menton) - the lowest point of the contour of the mandibular symphysis, N (Nasion) - most anterior point of nasofrontal suture in the midsagittal plane, Or (Orbitale) - the lowest point on the margin of the orbit, Pm (Suprapogonion) - point where curvature of the anterior contour of the symphysis changes from concave to convex, Po (Porion) - the midpoint on the upper edge of the external auditory meatus, S (Sella) middle point of sella turcica, PT – the junction of the pterygopalatine fossae and foramen rotundum located at the posterosuperior border of the averaged pterygopalatine fossae, Ba (Basion) – the lowest point on the anterior medial margin of the foramen magnum in the mid-sagittal plane, Pg (Pogonion) - the most anterior point on the symphysis of the mandible Constructional points Go (Gonion) – formed by the junction of the ramus with the lower border of the mandibular body on its posteroinferior aspect, FC (Facial centre) - intersection of the Frankfort plane and the perpendicular through the posterior side of the pterygomaxillary fissure (PTV), CC (Centre of the cranium) - the point of intersection between the BaN plane and the facial axis (PTGn) plane, Xi (Xilion) - the point placed in the center of the mandibular ascending ramus, determined by the Frankfort plane and pterygomaxillary fissure Cephalometric planes and lines PTV (Pterygoid vertical) – used to represent the posterior border of the maxilla. A line perpendicular to FH and tangent to the posterior contour of the PTM (Pterygomaxillary fossa) at the level of the foramen ovale. Anteroposterior extent of the anterior cranial base. Represents the cranial base in the mid-sagittal plane. ML (Mandibular plane) – a line tangent to the most prominent points on the lower border of the mandible, MLP - ML straight line perpendicular to passing through the Pg, NSL (Sella-Nasion plane) – anteroposterior extent of the anterior cranial base. Represents the cranial base in the mid-sagittal plane, FH (Porion-Orbitale plane, horizontal plane, Frankfurt plane) – represents the cranial base.