Relationship between Class III malocclusion and hyoid bone displacement during swallowing: a cine-magnetic resonance imaging study

Expert consensus on pediatric orthodontic therapies of malocclusions in children

Malocclusion, identified by the World Health Organization (WHO) as one of three major oral diseases, profoundly impacts the dental-maxillofacial functions, facial esthetics, and long-term development of ~260 million children in China. Beyond its physical manifestations, malocclusion also significantly influences the psycho-social well-being of these children. Timely intervention in malocclusion can foster an environment conducive to dental-maxillofacial development and substantially decrease the incidence of malocclusion or reduce the severity and complexity of malocclusion in the permanent dentition, by mitigating the negative impact of abnormal environmental influences on the growth. Early orthodontic treatment encompasses accurate identification and treatment of dental and maxillofacial morphological and functional abnormalities during various stages of dental-maxillofacial development, ranging from fetal stages to the early permanent dentition phase. From an economic and societal standpoint, the urgency for effective early orthodontic treatments for malocclusions in childhood cannot be overstated, underlining its profound practical and social importance. This consensus paper discusses the characteristics and the detrimental effects of malocclusion in children, emphasizing critical need for early treatment. It elaborates on corresponding core principles and fundamental approaches in early orthodontics, proposing comprehensive guidance for preventive and interceptive orthodontic treatment, serving as a reference for clinicians engaged in early orthodontic treatment.

Effect of orofacial myofunctional therapy along with preformed appliances on patients with mixed dentition and lip incompetence

BACKGROUND

Various preformed early orthodontic appliances for correcting oral habits and training orofacial muscles have emerged on the market. However, there are few reports on the effectiveness of these appliances for orofacial myofunctional training.

METHODS

This retrospective study evaluated children with lip incompetence and mixed dentition treated at the Pediatric Dentistry Department of Shanghai Ninth People's Hospital from 2016 to 2018. A total of 109 children (54 males, 55 females; age range: 7-10 years, mean age: 8.2 years) were selected from an overall sample of 870 patients. During the first visit, all patients were instructed to perform active lip and tongue training at home daily and were divided into two groups according to the kind of appliances worn. The first group consisted of 56 subjects (30 females; 26 males), with a mean age of 8.1 years (SD 1.1 years), treated with preformed appliances. The second group consisted of 53 subjects (25 females; 28 males), with a mean age of 8.2 years (SD 1.0 years), treated with conventional early orthodontic appliances (arch expansion devices along with "2*4" local fixed appliances). For each subject in the two groups, initial (pretreatment, T1) and final (posttreatment, T2) intraoral and external photos, dental casts, lateral cephalograms, and orthopantograms were taken, and lip strength was measured. SNA, SNB, ANB, APDI, FMA, U1SN, and IMPA before and after treatment were measured by The Dolphin Imaging Cephalometric Analysis Software. The hyoid bone position was also recorded. Differences between groups were identified with an independent sample t-test (P < 0.05).

RESULTS

In the first group, a statistically significant forward movement of the mandible was detected by an increase in SNB of - 1.06 degrees (P < 0.01) and an increase in APDI of - 2.23 degrees (P < 0.01). The increase in IMPA (- 3.21 degrees, P < 0.01) demonstrated a statistically significant protrusion of the lower incisors. Lip strength significantly increased (- 2.44, P < 0.01). The increase in HC3 (- 1 mm, P < 0.01) and HFH (- 2.95 mm, P < 0.01) implied a forward and downward movement of the hyoid bone. In the second group, a statistically significant forward movement of the mandible was also detected by an increase in APDI of -1.96 degrees (P < 0.01). Lip strength also significantly increased (- 1.24, P < 0.01). The increase in HFH (- 2.55 mm, P < 0.01) implied a downward movement of the hyoid bone. Compared with the treatment in the second group, orofacial myofunctional therapy combined with the preformed appliances led to a statistically significant lip strength increase (- 2.30, P < 0.05). Significant differences were observed in SNB and IMPA between the two groups (P < 0.05).

CONCLUSIONS

Orofacial myofunctional therapy effectively improved patient lip strength and was a good option for mixed dentition patients with lip incompetence. Preformed appliances could enhance the orofacial myofunctional therapy effect and result in significant improvements in lip strength and forward movement of the mandible, which can optimize the jaw relationship.

MRI in Dentistry- A Future Towards Radiation Free Imaging - Systematic Review

INTRODUCTION

Magnetic Resonance Imaging (MRI), being a technique with huge potential, has become the primary diagnostic investigation for many clinical problems. Its application now has been successfully used in dentistry to maximize the diagnostic certainty.

AIM

The present review aims to analyze the applicability, feasibility and efficacy of MRI in the field of dentistry.

MATERIALS AND METHODS

A literature search was performed in main databases like Pub Med Central, Cochrane Library, Embase and Google Scholar from 1970 up to December 2015. The 2672 titles that appeared, 25 fulfilled the criteria and were included in the review. Two articles were hand searched and three articles through e-mail were also included.

RESULTS

The review highlights the increasing role of MRI in dentistry. In the available literature, it was found that T1 and T2 weighted images were the acceptable diagnostic images for detection of dental related diseases.

CONCLUSION

MRI can be used in diagnosis and treatment planning of implants, jaw lesions, diseases of Temporomandibular Joints (TMJ), orthodontic treatment, endodontic treatment etc., to achieve better prognosis.