Oral perception in tongue thrust and other oral habits

Evaluation of the Association of Oral Stereognosis with Malocclusion in Children

Aim and objective

To evaluate the association between oral stereognosis with malocclusion in children.

Materials and methods

Stereognostic investigation was made with a set of seven different geometric configurations (circle, square, triangle, star, clover, diamond, and heart shapes) cut out from fresh, raw carrots using preformed iron molds. Any five of the seven geometric forms were randomly placed inside the mouth on the dorsum of the tongue by the investigator with the subject's eyes closed. A minimum of three shapes correctly identified out of the five offered to each child was considered as an indicator of the adequate stereognostic ability of that particular child.

Results

Among the children under Index of Orthodontic Treatment Needs (IOTN) grade I group, 82.4% of children came under the positive response group. Among IOTN grades II, III, and IV, the percentages of children with positive responses were 72.1%, 58.1%, and 18.8%, respectively. There is a statistically significant (p < 0.001) decrease in positive response with increasing IOTN grades.

Conclusion

The observations from the present study show that there is altered oral sensory perception in children graded as with malocclusion according to the index used and belonging to the age group selected in the study.

Clinical significance

Sensory and motor components of the orofacial region, like any other part of the human body, are inseparable in their structure and function, the association between orofacial growth and development and sensory maturation cannot be overlooked.

How to cite this article

Janardhanan R, Soman A, George S, et al. Evaluation of the Association of Oral Stereognosis with Malocclusion in Children. Int J Clin Pediatr Dent 2021;14(S-1):S18–S21.

Prediction of oral discomfort and dysfunction in lingual orthodontics: a preliminary report

INTRODUCTION

The purpose of this prospective study was to examine the influence of malocclusion on the amount of discomfort of patients who were treated with Incognito lingual brackets (T.O.P. Service, Ormco, Amersfoort, the Netherlands; ibraces in North and South America, Lingualcare, Dallas, Tex).

METHODS

Twenty-one female patients (mean age, 24.8 years; SD 10.7) participated in the investigation and completed a standardized questionnaire before and the day after placement of the appliance. One experienced orthodontist, blinded to the results of the questionnaires, evaluated their initial cephalograms and casts with respect to the parameters SNA, SNB, and ANB angles; overjet; overbite; maxillary and mandibular anterior contact-point displacement; crossbite; open bite; and missing teeth.

RESULTS

Malocclusion measured on the casts had no significant impact on the amount of discomfort or dysfunction reported by the patients. The SNA (r = -0.619, P = .003) and SNB (r = -0.615, P = .003) angles, however, correlated significantly with the restriction of tongue space; patients with an SNB angle that was smaller than 1 SD from the norm were significantly more prone to experience severe restriction of tongue space (P = .003).

CONCLUSIONS

The SNA and SNB angles are predictors for the level of tongue-space restriction after placement of lingual brackets: the smaller the angles, the more prone the patients are to experience discomfort.

Establishing a reliable protocol to measure tongue sensation

The relationship between tongue sensation and tongue function for speech, mastication and deglutition are growing areas of interest among rehabilitative professionals. To determine the potential effect that sensation has on function, it is imperative that, first, reliable and valid measures of tongue sensation be established. The aim of this study was to develop a protocol to test tongue sensation across a spectrum of sensory functions that included two-point discrimination, light-touch discrimination, thermal sensation, texture recognition, oral stereognosis and taste recognition. Materials tested within each domain respectively included: (i) the MacKinnon-Dellon Disk-criminator, paperclip and caliper; (ii) the Semmes-Weinstein monofilament and cotton wisp; (iii) dental mirrors and glass test tubes; (iv) spheres of textured acrylic resin on rods; (v) acrylic resin forms with differing shapes on rods and (vi) salty, sweet, sour, bitter and neutral solutions. Materials were tested on 40 healthy subjects between the ages of 20 and 55. The results from this study indicated that thermal, texture and taste sensations appear robust for accuracy and discrimination. Two-point discrimination and light touch seem to be influenced by location of stimulation on the tongue and force applied, whereas stereognosis was influenced by stimulus complexity. The results of this study indicate that clinicians may choose instruments as practical as paperclips and test tubes for testing two-point discrimination and thermal sensation, respectively. For the other sensations, it may be important to use more sophisticated instrumentation to control variables of force, surface area stimulated and assessing sensations in graded steps.

Relationship between oral sensitivity and masticatory performance

The size of a bolus determines how it will be manipulated in the mouth and swallowed. We hypothesized that mucosal sensitivity would be important for masticatory function. The accuracy of solid object size perception, spatial acuity, and food particle size reduction during mastication were measured in 22 healthy adults with/without topical anesthesia of their oral mucosa. Topical anesthesia had no effect on the perception of sphere sizes, but significantly reduced spatial sensitivity. Without anesthesia, there was a correlation between an individual's ability to perceive the sizes of steel spheres (diameter, 4-9 mm) and the sizes of food particles chewed for 15 cycles and at swallowing. There was no correlation between spatial sensitivity and food particle size. We suggest that the stimuli used to test two-point discrimination stimulates only superficial receptors, which involve light touch and are easily anesthetized, while the spheres might excite more deeply-set receptors. The latter appear to be more important for masticatory performance and swallowing.

Speech performance in lingual orthodontic patients measured by sonagraphy and auditive analysis

Esthetically appealing, externally invisible, lingually applied orthodontic brackets are in increasing demand. Because the brackets are placed lingually, however, they appear to cause some problems with respect to speech. This study is the first to present a prospective evaluation of the articulation of 23 patients with lingual brackets by means of an innovative combination of test methods. An acoustic, objective evaluation of articulation measured by digital sonagraphy was related to a semiobjective auditive evaluation by 10 speech professionals, to a semiobjective auditive evaluation by close contacts of the patients, and to a subjective auditive evaluation by the patients themselves, the latter 2 using standardized questionnaires. The tests were performed before (T1), within 24 hours after (T2), and 3 months (+/- 1 week) after (T3) the start of therapy. In comparison with the initial findings, a significant deterioration in articulation was recorded with all test methods at T2 and T3. Using a new combination of methods, our investigations show the need for detailed briefing of patients about the extent and duration of changes in speech resulting from lingual brackets.