Lip incompetence and myofunctional therapy

Lip incompetence, which is a state in which the upper and lower lips are constantly apart, is thought to induce mouth breathing that may result in the development of gingivitis and periodontal disease. In the orthodontic field, lip incompetence has major problems for diagnosis, when determining the treatment goal and at the time of retention. We have been performing studies on lip incompetence and have obtained the following results : (1) it is possible to predict to some extent the state of lip closure during sleep by examination only in an awake state, (2) anterior teeth are positioned forward in individuals with lip incompetence, and (3) a training method called Button Pull is effective as a myofunctional therapy for improving lip incompetence, but there remains a need to clarify the background

Study of training for improving lip incompetence

Purpose: We have been using myofunctional therapy in orthodontic treatment to improve orofacial disorders. Our previous study showed that lip training increased orbicularis oris muscle strength and endurance. The aim of this study was to determine the effectiveness of hypoxic lip training for improving lip incompetence. Subjects and methods: Twenty healthy subjects (10 males and 10 females, 23.6 +/- 2.3 years old) with lip incompetence participated in this study. We recorded the sealed lip ratio calculated by using the formula "(lip-sealingtime/totalrecorded time) x 100" during relaxation (listening to soothing music) and during concentration (performing a mathematical calculation). Then the subjects performed a standardized hypoxic lip training (5 repetitive contractions with 80% of maximum tensile strength of the orbicularis oris muscle) with a traction plate. Training was repeated daily for 4 weeks. To estimate training effects, the sealed lip ratios during relaxation and concentration were recorded before training (T1), at 2 weeks (T2) and 4 weeks (T3) after the start of training, and at 4 weeks (T4) and 8 weeks (T5) after the end of training. Results: The sealed lip ratios in both the relaxation and concentration conditions significantly (p < 0.003 after Bonferroni correction) increased during the training period. Although the sealed lip ratios slightly decreased during the post-training period, they were not significantly different from those at T3. Conclusions: Hypoxic lip training increases the sealed lip ratio and is thus effective for improving lip incompetence. Sealed lip ratios were maintained after 8 weeks of training. (C) 2016 Published by Elsevier Ltd

Orthodontic force, tooth movement, and interleukin-1β

This review presents the basic knowledge and understanding of the biological processes involved in the orthodontic force and tooth movement. It also explains one of the basic inflammatory markers that was the “interleukin-1β” (IL-1β). Because orthodontic mechanic has to be carefully used during treatment, traumatic effects on the periodontium and teeth may occur. Proper understanding of biological events will help design orthodontic force that will produce minimal tissue damage. In addition, inflammatory markers such as IL-1β play a critical role in bone remodeling and tooth movement. This may be of benefit in understanding how it works and the relevance of the concepts to clinical practice

Microvasculature of Dental Pulp in a Rat Molar in an Occlusal Hypofunctional Condition

In clinical orthodontics, hypofunctional teeth are a common problem as it is necessary to move these teeth to be able to restore the occlusal function. Previous studies reported that hypofunctional occlusion could lead to atrophic changes in the microvasculature of the periodontal ligament. However, there is a lack of empirical research on the relationship between hypofunctional occlusion and microvasculature of dental pulp. The purpose of this study is to elucidate details of changes in pulpal microvasculature in the occlusal hypofunctional condition. Twenty-four 7-week-old male Wistar rats were divided into 4 groups: 1 week, 1 month, 3 months, and 6 months after extraction of opposing teeth. To establish an occlusal hypofunctional condition, maxillary left first and second molars were extracted. The mandibular left molar region was used as the experimental group and the opposite sides of the mandible in the same animals were used as the control group. Paraffin cross-sections of the mandibular first molars were stained with hematoxylin-eosin for light microscopic observations. In this study, the terms “Pulpal vascular area” and “Pulp cell nuclear area” refer to the total blood vessel crosssectional area of the dental pulp and the total nuclear area of the dental pulp cells, respectively. The pulpal vascular area and the pulp cell nuclear area in the mesial half of the mandibular first molars were examined at 3 places: 1） in the pulp horn zone, 2） the middle zone, and 3） the root apex zone. All data were expressed as percentages of the measured area. Comparisons of the data in the two groups were performed. The percentages of the vascular area and pulp cell nuclear area in the pulp horn zone were statistically significantly smaller in the experimental group than in the control group at 1 month, 3 months and 6 months, while there were no statistically significant differences between the two groups was observed in the middle and root apex areas. The results suggest that occlusal stimulation affects the microvasculature and the cellular density of the dental pulp in the coronal area of teeth

RANKL regulates differentiation of microfold cells in mouse nasopharynx-associated lymphoid tissue (NALT)

Murine nasopharynx-associated lymphoid tissue (NALT), located at the base of the nasal cavity, serves as a major site for the induction of mucosal immune responses against airway antigens. The follicle-associated epithelium (FAE) covering the luminal surface of NALT is characterized by the presence of microfold cells (M cells), which take up and transport luminal antigens to lymphocytes. Glycoprotein 2 (GP2) has recently been identified as a reliable marker for M cells in Peyer's patches of the intestine. However, the expression of GP2 and other functional molecules in the M cells of NALT has not yet been examined. We have immunohistochemically detected GP2-expressing cells in the FAE of NALT and the simultaneous expression of other intestinal M-cell markers, namely Tnfaip2, CCL9, and Spi-B. These cells have been further identified as M cells because of their higher uptake capacity of luminal microbeads. Electron microscopic observations have shown that GP2-expressing cells on the FAE display morphological features typical of M cells: they possess short microvilli and microfolds on the luminal surface and are closely associated with intraepithelial lymphocytes. We have also found that the receptor activator of nuclear factor kappa-B ligand (RANKL) is expressed by stromal cells underneath the FAE, which provides its receptor RANK. The administration of RANKL markedly increases the number of GP2+Tnfaip2+ cells on the NALT FAE and that of intestinal M cells. These results suggest that GP2+Tnfaip2+ cells in NALT are equivalent to intestinal M cells, and that RANKL-RANK signaling induces their differentiation

maxillofacial features of Apert syndrome

Apert syndrome is a rare craniosynostosis syndrome characterized by irregular craniosynostosis, midface hypoplasia, and syndactyly of the hands and feet. Previous studies analyzed individuals with Apert syndrome and reported some facial and intraoral features caused by severe maxillary hypoplasia. However, these studies were performed by analyzing both individuals who had and those had not received a palate repair surgery, which had a high impact on the maxillary growth and occlusion. To highlight the intrinsic facial and intraoral features of Apert syndrome, five Japanese individuals with Apert syndrome from 5 years and 2 months to 9 years and 10 months without cleft palate were analyzed in this study. A concave profile and a skeletal Class III jaw-base relationship caused by severe maxillary hypoplasia were seen in all patients. The patients exhibited anterior and posterior crossbites possibly due to a small dental arch of Maxilla