Shape and Symmetry of Human Condyle and Mandibular Fossa
Total Page：16
File Type：pdf, Size：1020Kb
Int. J. Odontostomat., 9(1):65-72, 2015. Shape and Symmetry of Human Condyle and Mandibular Fossa Forma y Simetría del Cóndilo Humano y Fosa Mandibular Eduardo Cotecchia Ribeiro* ; Monique Lalue Sanches* * ; Luis Garcia Alonso* * * & Ricardo Luiz Smith* * * * RIBEIRO, E. C.; SANCHES, M. L.; ALONSO, L. G. & SMITH, R. L. Shape and symmetry of human condyle and mandibular fossa. Int. J. Odontostomat., 9(1):65-72, 2015. ABSTRACT: The aim of the study was to determine and classify the shape of the mandibular fossa and the corresponding condyle in different types, relating them to sex and symmetry, in adult human skulls, from lateral, posterior and superior views. The sample included 50 human skulls from 23 to 82 years old, 32 males and 18 females. The condyle and silicone casting molds of the fossa were photographed to assess shape in the three views. Shapes were classified, validated by intra- and inter-rater analysis and frequency, sex distribution and symmetry verified. Shapes were classified as rounded, angled, flattened and mixed types in the lateral and posterior views; and as biconvex, flat-convex, biflattened and mixed in the superior view. Rounded condyle and fossa were more frequent in the lateral (57% and 66% respectively) and posterior (53% and 83%) views. In the superior view, mixed shape presented higher frequency in condyle (59%) while in fossa the biconvex shape (46%) was most common. There was no significant difference in shape distribution by sex. The same shape (symmetry) or otherwise (non-symmetry) in right and left side condyle and fossa were separately assessed and showed various combinations. KEY WORDS: temporomandibular joint, condyle, mandibular fossa, anatomy, shape, symmetry. INTRODUCTION The temporomandibular joint (TMJ) is a complex, The bone components of TMJ need careful study highly specialized joint, and there is nothing compara- and understanding for the simple reason that changes ble in the human skeleton. Anatomical knowledge of the in them imply functional disorders (temporomandibular TMJ is one of the foundations of clinical practice, allowing disorders - TMD) and pain, that are widely discussed understanding pathological alterations, diagnostic in the literature. evaluation through the resources of image diagnostics, and choice of appropriate therapeutic paths. The large topographical variability between the condyle and fossa is affected by the shape of the former Among the anatomic characteristics is the which suffers changes due to bone remodelment. In presence of an articular disk which guarantees the absence of condyle the fossa remains shallow, geometrical adaptation between joint faces. This disk maintaining the characteristics found in a newborn of dense connective tissue totally divides the joint cavity (Pandis et al., 1991). in upper compartment, where translational and lateral movements take place through sliding, and lower When there is congenital bilateral condyle compartment, where rotational movement takes pla- absence, morphogenesis constantly functions in ce. These two compartments are morphologically and seeking architectonic balance among the isolated parts functionally independent. (Enlow & Hans, 2002). * Associate Professor, Department of Morphology, Universidade Federal de São Paulo, São Paulo, Brazil. ** Preceptor, Department of Morphology, Universidade Federal de São Paulo, São Paulo, Brazil. *** Adjunct Professor, Department of Morphology, Universidade Federal de São Paulo, São Paulo, Brazil. **** Professor, Department of Morphology, Universidade Federal de São Paulo, São Paulo, Brazil. 65 RIBEIRO, E. C.; SANCHES, M. L.; ALONSO, L. G. & SMITH, R. L. Shape and symmetry of human condyle and mandibular fossa. Int. J. Odontostomat., 9(1):65-72, 2015. Most authors discussing the anatomical Skulls were selected randomly from the 440 in (reciprocal position) and functional relation between the collection. Inclusion criteria were: specimen condyle and fossa, including during development, integrity; absence of evident deformations or identified generically consider the fossa with a rounded shape or, pathologies; and the presence of teeth or dental alveoli. even, as being simply a depression in the squamous part of the temporal bone where the condyle articulates The condyle and mandibular fossa of skulls (Moore & Dalley, 2007), without seeking to classify were evaluated for shape. Right and left condyle were different shapes. Descriptions and consequential photographed (Sony digital camera -- Mavica® – FD classifications of the fossa shape are rare in the 90), maintaining a fixed distance of 30 cm in the late- literature. A few authors have examined condyle and ral, posterior and superior views. Molds of the fossa morphology in computed tomography (CT) images corresponding right and left fossa were obtained using obtained from patients with TMD and non-patients, silicon (Otoform R/C – dimethylpolysiloxane). Then describing four fossa shapes (Raustia & Pyhtinen, 1990). molds representing the fossa impressions were Others have analyzed the shape and location of the photographed in the same manner as the condyle in fossa and its relation with mandibulofacial asymmetry the same positions. by means of dry-skull Xrays (Pirttiniemi & Kantomaa, 1992). One author described the fossa as deeply Our findings were based on the analysis of concave sagitally, slightly concave transversally and different shapes, whose evaluation was considered the wider laterally (Gray et al., 1995). structure profile (condyle and fossa mold) according to a geometric criterion. This has not been the case for condyle, where shape classification has been presented by numerous In the lateral and posterior views, the shapes authors. There have been studies through the direct classified were: method in dry skulls (Yale et al., 1963; 1966; Mongini, 1977; Matsumoto & Bolognese, 1995); dry-skull Xrays Rounded – profile predominance of a circumferential (Yale, 1969; Pandis et al.) and others on mandibles arch; obtained from autopsy (Takenoshita, 1982); CT in Angled – profile slope at acute angle; patients with TMD, related to remodelation with dental Flattened – predominance of flattened profile abrasion (Mongini), in healthy individuals (Christiansen (“straight”); et al., 1987), and in patients with TMD and non-patients Mixed – combination of the previous or irregular. (Raustia & Pyhtinen). In the superior view, the shapes classified were: Viewing the bibliographic search, the scarcity of works related to the specific theme proposed and the Biconvex – convex anterior and posterior borders; morphological and clinical interest that the TMJ exci- Flat-convex – flat anterior border (“straight”) and convex tes, we were able to define the objective of the present posterior; study, to wit, determine and classify the mandibular Biflattened – anterior and posterior borders flat fossa and corresponding condyle shape for different (“straight”); types as regards sex and symmetry in adult human Mixed – combination of the previous or irregular. skulls from lateral, posterior and superior views. Intra- and inter-rater analyses were used to check observations, involving a blind evaluation of the MATERIAL AND METHOD shape of the 100 condyles and the 100 corresponding fossa molds by the researcher at two distinct times, and then by another professor of Anatomy. Statistical analysis The sample consisted of 50 adult human skulls of the intra- and inter-rater observations was done with (23 to 82 years old), with 32 male and 18 female, Chi squared test, through a linear correlation to verify without designation relative to ethnic group, and the extent of association and using a 5% level of belonging to Museum of Anatomy Collection of the significance. Federal University of Sao Paulo – Paulista School of Medicine (UNIFESP-EPM). The study was approved A descriptive, non-parametric statistical test (Chi by the Research Ethics Committee at UNIFESP-EPM squared) was used for analysis of variables, considering with the 0080/02 protocol number. a 5% level of significance (Siegel & Castellan Jr., 2006). 66 RIBEIRO, E. C.; SANCHES, M. L.; ALONSO, L. G. & SMITH, R. L. Shape and symmetry of human condyle and mandibular fossa. Int. J. Odontostomat., 9(1):65-72, 2015. RESULTS analyses, shape frequencies, shape distribution by sex and shape symmetry. Findings refer to the classification of the shapes Shape classification of the condyle and of the condyle and fossa molds, intra- and inter-rater mandibular fossa mold Shapes were classified for the lateral, posterior and superior views. A – Lateral view, shapes: rounded, angled, flattened and mixed (combination of the Fig.1 Condyle shapes left to right: rounded, angled, flattened and mixed. previous); condyle (Fig. 1) and fossa mold (Fig. 2). B – Posterior view, shapes: rounded, angled, flattened and mixed (combination of the previous); condyle (Fig. 3) and fossa mold (Fig.4). Fig.2. Fossa mold shapes left to right: rounded, angled, (flattened not found) and mixed. C – Superior view, shapes: biconvex, flat-convex, biflattened and mixed (combination of the previous); condyle (Fig.5) and fossa mold (Fig.6). Fig.3. Condyle shapes left to right: rounded, angled, flattened and mixed. Results of the intra-rater (test, retest) and inter-rater analyses were not statistically significant. Frequency of shapes. Sample distribution of condyle Fig.4. Fossa mold shapes left to right: rounded, angled, flattened and mixed. and mandibular fossa mold shapes is presented for the three views,