Tongue volume in adults with skeletal Class III dentofacial deformities

Head & Face Medicine, Mar 2016

Background The size of the tongue is implicated as an essential etiological factor in the development of malocclusions. The aim of our study was to assess tongue size in skeletal Class III (SCIII) patients in comparison to adults with normal occlusion, using three-dimensional (3D) ultrasound. Methods The SCIII group consisted of 54 subjects; 34 females and 20 males and the control group contained 36 subjects, 18 from each gender with Class I relationship. 3D ultrasound images of the tongues were acquired, and then the tongues’ volumes were assessed. Results The males in both the SCIII and control groups had significantly larger tongue volumes than the female subjects (mean SCIII 100.8 ± 6.3 and control 92.4 ± 9.8 cm 3 in males vs. SCIII 77.4 ± 10.2 and control 67.2 ± 5.6 cm 3 in females). The highly significantly larger tongue volumes were in SCIII patients of both genders (p were less than 0.01 for female and 0.03 for male). The tongue volumes within the whole SCIII group were significantly larger with more negative Wits values. Conclusion The tongue volumes are significantly bigger in SCIII subjects than normal. Larger tongues correlate with more severe SCIII. The clinical importance of this data is that limited mandibular setback planning is necessary to prevent narrowing of respiratory airways.

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Tongue volume in adults with skeletal Class III dentofacial deformities

Ihan Hren and Barbič Head & Face Medicine Tongue volume in adults with skeletal Class III dentofacial deformities N. Ihan Hren 0 U. Barbič 0 0 Department of Maxillofacial and Oral Surgery, University Medical Centre Ljubljana , Zaloška cesta 2, 1000 Ljubljana , Slovenia Background: The size of the tongue is implicated as an essential etiological factor in the development of malocclusions. The aim of our study was to assess tongue size in skeletal Class III (SCIII) patients in comparison to adults with normal occlusion, using three-dimensional (3D) ultrasound. Methods: The SCIII group consisted of 54 subjects; 34 females and 20 males and the control group contained 36 subjects, 18 from each gender with Class I relationship. 3D ultrasound images of the tongues were acquired, and then the tongues' volumes were assessed. Results: The males in both the SCIII and control groups had significantly larger tongue volumes than the female subjects (mean SCIII 100.8 ± 6.3 and control 92.4 ± 9.8 cm3 in males vs. SCIII 77.4 ± 10.2 and control 67.2 ± 5.6 cm3 in females). The highly significantly larger tongue volumes were in SCIII patients of both genders (p were less than 0.01 for female and 0.03 for male). The tongue volumes within the whole SCIII group were significantly larger with more negative Wits values. Conclusion: The tongue volumes are significantly bigger in SCIII subjects than normal. Larger tongues correlate with more severe SCIII. The clinical importance of this data is that limited mandibular setback planning is necessary to prevent narrowing of respiratory airways. Skeletal Class III; Tongue; Volume Background Skeletal class III (SCIII) better known as mandibular prognathism in spite the fact that this term describes only one form of this dentofacial deformity. It is a severe dentofacial disharmony which frequently shows combinations of skeletal and dentoalveolar characteristics resulting in different facial appearances. The common characteristic is changed anteroposterior relationship between maxilla and mandible with their changed sizes and positions in relation to the anterior cranial base. The more common clinical sign of that is Class III dental malocclusion. The etiology of SCIII appears to be a result of interactions amongst the genetically determined factors and many internal and external environmental factors but the precise roles of both have as yet to be clarified. Amongst them traditionally the muscle equilibrium among intraoral and buccal forces has been understood for the normal development of dental arches but this simple theory was revisited because any equilibrium between the force of the tongue and the force of lips couldn’t be found [ 1 ]. It is hypothesised that the tongue volume, besides posture and function, is of crucial importance in the etiology of malocclusions and dentofacial deformities [ 2 ]. Macroglossia and its consequences are well-known in Beckwith-Wiedemann syndrome [ 3 ] and acromegaly [ 4 ], it was suggested as a possible cause of open bite and mandibular prognathism [ 5 ]. However the role of tongue volume in mandibular prognathism was also rejected [ 6 ]. The studies of tongue reductions have reported about changing the skeletal Class III into Class I in the early preadolescent period [ 7 ] and about dental arch lingual collapse after a decrease in tongue volume [ 8 ]. Clinical studies have reported that tongue volume is correlated with mandibular arch size [ 9 ], vertical facial height, and chin position [ 6 ]. The dilemma is longstanding about tongue adaptation to existing oral morphology or actively moulding its surrounding tissues [ 10, 11 ]. So determining the size of the tongue in different facial morphological variants and the examination of other possible tongue roles such as pressure, mobility, and rest postures are still to be clarified. It has also been suggested that an increase in the volume of soft tissues induces osteogenic reaction at the growth site of the bone. With the relative increase of tongue volume, which means a decreased volume of the oral cavity as consequence of orthognathic surgical procedures with normal volume of the tongue, the relapse can be explained and indications for tongue reductions determined [12]. The aim of this study was to evaluate the tongue size at its normative volume in SCIII patients in comparison to patients with normal occlusion using three-dimensional ultrasound as valid and non-invasive methods. Therefore, the null hypothesis assumes that there is insignificant correlation between the tongue volume and the maxillamandibular relationship CIII. Methods The study was approved by the Ethics Committee of the Republic of Slovenia, and informed consents were obtained from all subjects involved in the study. The SCIII group consisted of 54 subjects, 34 females (aged 25.5 ± 10.3 years) and 20 males (aged 21.5 ± 4.6 years), with Class III molar relationships, negative overjet and skeletal defo (...truncated)


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N. Ihan Hren, U. Barbič. Tongue volume in adults with skeletal Class III dentofacial deformities, Head & Face Medicine, 2016, pp. 12, 12, DOI: 10.1186/s13005-016-0110-4