Takakazu Yagi

Maxillary Anterior Segmental Distraction Osteogenesis with the Dynaform System for Severe Maxillary Retrusion in Cleft Lip and Palate

Midfacial retrusion and velopharyngeal incompetence are the two major challenges in the treatment of cleft lip–cleft palate. Any simultaneous maxillary advancement procedure that includes Le Fort osteotomy, which is considered to be the most common and the safest procedure for correction of maxillary retrusion, may result in velopharyngeal incompetence or deterioration of hypernasality.1,2 There have been a number of reports recently that describe the advantages of distraction osteogenesis in combination with Le Fort osteotomy for cleft palate patients, with which the patient’s maxilla can be advanced with soft tissue in the distraction segment being regenerated.3–8 Some reports also suggest that the incidence of velopharyngeal incompetence is low with the abovementioned procedure except for cases that require excessive advancement.3,4 It is clear, however, that this procedure may sometimes induce a morphologic change in the pharynx. Also, there is a study showing that the risk of deterioration of hypernasality following maxillary distraction osteogenesis with the Rigid External Distraction system (KLS-Martin, L.P., Tuttlingen, Germany) is as high as that following simultaneous maxillary advancement.9 Nevertheless, it is true that morphologic changes of the velopharynx following maxillary distraction osteogenesis may cause velopharyngeal incompetence. Therefore, future discussion is required with regard to velopharyngeal function following maxillary distraction osteogenesis based on a large number of case reports. An ideal treatment of maxillary retrusion in cleft palate patients must correct the deformity without affecting the patient’s velopharyngeal function and diminish the frequency of simultaneous mandibular osteotomy in case the patient has a normally grown mandible. In recent years, reports have been presented regarding maxillary anterior segmental distraction osteogenesis that does not affect the morphologies in the posterior part of the oral cavity including the nasopharynx.10–12 This procedure has not been used widely yet because a standardized surgical technique has not been established. With the intention of establishing a standardized maxillary anterior segmental distraction osteogenesis for cleft patients, we developed a new conventional procedure using a mandibular distractor13 (Dynaform system; Stryker Leibinger Micro Implants, Kalamazoo, Mich.) as a palatal distractor in 2002. So far, we have applied this procedure in several cases with a severely retruded maxillary bone and have obtained satisfying clinical results in both velopharyngeal function and advancement of bone segment. The following report is intended to detail the procedure of this new maxillary anterior segmental distraction osteogenesis method by presenting a typical case treated with this procedure. From the First Department of Oral and Maxillofacial Surgery and Department of Orthodontology, Osaka University Graduate School of Dentistry, and Department of Orthodontology, Asahi University, Graduate School of Dentistry. Received for publication June 20, 2005; accepted December 29, 2005. Copyright ©2007 by the American Society of Plastic Surgeons

Posterior scissors-bite: masticatory jaw movement and muscle activity

Scissors-bite is a malocclusion characterised by buccal inclination or buccoversion of the maxillary posterior tooth and/or linguoclination or linguoversion of the mandibular posterior tooth. This type of malocclusion causes reduced contact of the occlusal surfaces and can cause excessive vertical overlapping of the posterior teeth. This case-control study is the first to evaluate both masticatory jaw movement and masseter and temporalis muscle activity in patients with unilateral posterior scissors-bite. Jaw movement variables and surface electromyography data were recorded in 30 adult patients with unilateral posterior scissors-bite malocclusion and 18 subjects with normal occlusion in a case-control study. The chewing pattern on the scissors-bite side significantly differed from that of the non-scissors-bite side in the patients and of the right side in the normal subjects. These differences included a narrower chewing pattern (closing angle, P < 0.01; cycle width, P < 0.01), a longer closing duration (P < 0.05), a slower closing velocity (P < 0.01) and lower activities of both the temporalis (P < 0.05) and the masseter (P < 0.05) muscles on the working side. In 96% of the patients with unilateral posterior scissors-bite, the preferred chewing side was the non-scissors-bite side (P = 0.005). These findings suggest that scissors-bite malocclusion is associated with the masticatory chewing pattern and muscle activity, involving the choice of the preferred chewing side in patients with unilateral posterior scissors-bite.

Influence of maximum bite force on jaw movement during gummy jelly mastication

It is known that maximum bite force has various influences on chewing function; however, there have not been studies in which the relationships between maximum bite force and masticatory jaw movement have been clarified. The aim of this study was to investigate the effect of maximum bite force on masticatory jaw movement in subjects with normal occlusion. Thirty young adults (22 men and 8 women; mean age, 22.6 years) with good occlusion were divided into two groups based on whether they had a relatively high or low maximum bite force according to the median. The maximum bite force was determined according to the Dental Prescale System using pressure-sensitive sheets. Jaw movement during mastication of hard gummy jelly (each 5.5 g) on the preferred chewing side was recorded using a six degrees of freedom jaw movement recording system. The motion of the lower incisal point of the mandible was computed, and the mean values of 10 cycles (cycles 2-11) were calculated. A masticatory performance test was conducted using gummy jelly. Subjects with a lower maximum bite force showed increased maximum lateral amplitude, closing distance, width and closing angle; wider masticatory jaw movement; and significantly lower masticatory performance. However, no differences in the maximum vertical or maximum anteroposterior amplitudes were observed between the groups. Although other factors, such as individual morphology, may influence masticatory jaw movement, our results suggest that subjects with a lower maximum bite force show increased lateral jaw motion during mastication.

The role of ghrelin in patients with functional dyspepsia and its potential clinical relevance (Review)

Functional dyspepsia (FD) is a functional gastrointestinal disorder (FGID). According to the Rome III consensus, FD is divided into 2 subgroups: epigastric pain syndrome (EPS) and postprandial distress syndrome (PDS). Although multiple mechanisms of FD pathogenesis have been suggested, its underlying etiology and pharmacological therapy remain unclear. Ghrelin is a gut-derived peptide found in the stomach. It plays a role in the regulation of gastric motility and appetite. The ghrelin gene encodes 3 molecular forms, acyl ghrelin, des-acyl ghrelin and obestatin. Acyl ghrelin acts as an endogenous ligand for growth hormone secretagogue receptor; furthermore, it is orexigenic, with effects on food intake, energy homeostasis and gastrointestinal motility. Des-acyl ghrelin exerts an opposite effect to acyl ghrelin. Obestatin exerts an inhibitory effect on the motor activity of the antrum and duodenum in fed animals. These peptides exert differential effects on gut motility and food intake. The therapeutic potential of ghrelin has attracted attention due to its varied bioactivities. Certain studies have shown that total ghrelin levels are significantly lower in patients with FD compared with healthy volunteers and that the acyl ghrelin levels of patients with FD are higher compared with healthy volunteers. However, a recent study demonstrated that acyl ghrelin levels in patients with PDS were lower compared with healthy volunteers; the association between FD and other ghrelin family gene products also remains unclear. Although certain studies have demonstrated the beneficial effects of acyl ghrelin administration and its agonist in patients with FD, only a few clinical reports exist. Further studies are required in order to examine the effects of ghrelin on FD.

The Role of Zinc in the Treatment of Taste Disorders

In the 1990s the number of patients diagnosed with taste disorders in the USA and Japan was over one million people each year, and the number is increasing annually. Taste disorders are caused by several factors such as genetic disease, head trauma, structural changes, glossodynia, cancer, change of lifestyle, and more. The role of zinc in the treatment of taste disorders has been studied since the oral administration of zinc by patients was reported to improve their taste disorders. Carbonic anhydrase (CA), a zinc metalloenzyme, has also been studied in association with taste disorders, since the regulation of serum CA levels was shown to influence the effect of orally administrated zinc in the treatment of taste disorders. Zinc is an essential trace element that contributes to the active center of approximately 300 enzymes. Studies have revealed that zinc is involved in various physiological functions. Moreover, some medications have been shown to induce a zinc deficiency, which has been associated with a variety of clinical conditions. Hence, since the relationship between taste disorder and serum zinc concentration has been discussed for long time, taste disorder may be useful in diagnosing zinc deficiency. Moreover, it appears that medicines of the zinc-containing supplement type contribute to the treatment of taste disorders caused by zinc deficiency. Orally administered zinc has been shown to directly stimulate food intake via neuropeptide in the hypothalamus. Therefore, zinc administration may potentially be used to treat taste disorders, as well as several other diseases by stimulating feeding. The article presents some promising patents on the role of zinc in the treatment of taste disorders.

The Role of Ghrelin, Salivary Secretions, and Dental Care in Eating Disorders

Eating disorders, including anorexia and bulimia nervosa, are potentially life-threatening syndromes characterized by severe disturbances in eating behavior. An effective treatment strategy for these conditions remains to be established, as patients with eating disorders tend to suffer from multiple relapses. Because ghrelin was originally discovered in the stomach mucosa, it has been widely studied over the past decade in an effort to uncover its potential roles; these studies have shed light on the mechanism by which ghrelin regulates food intake. Thus, studying ghrelin in the context of eating disorders could improve our understanding of the pathogenesis of eating disorders, possibly resulting in a promising new pharmacological treatment strategy for these patients. In addition, early detection and treatment of eating disorders are critical for ensuring recovery of young patients. Oral symptoms, including mucosal, dental, and saliva abnormalities, are typically observed in the early stages of eating disorders. Although oral care is not directly related to the treatment of eating disorders, knowledge of the oral manifestations of eating disorder patients may aid in early detection, resulting in earlier treatment; thus, oral care might contribute to overall patient management and prognosis. Moreover, ghrelin has also been found in saliva, which may be responsible for oral hygiene and digestion-related functions. This review discusses the pharmacological potential of ghrelin in regulating food-intake and the role of saliva and oral care in young patients with eating disorders.

Patient with oculo-facio-cardio-dental syndrome treated with surgical orthodontics

Oculo-facio-cardio-dental (OFCD) syndrome is a rare syndrome characterized by ocular, facial, cardiac, and dental disorders. Only about 20 cases have been reported to date. The most prominent of the various features of this syndrome is canine radiculomegaly. Other features include a long and narrow face, a high nasal bridge, a broad and pointed nose, a bifid nose, ear deformity, cleft palate or submucous cleft palate, maxillary growth retardation, a large gonial angle, open apices, delayed eruption, persistent deciduous teeth, extreme overbite, and constricted maxilla. Orthodontic and prosthodontic treatment has been reported for several patients, but surgical-orthodontic treatment for OFCD has not been reported. An 18-year-old woman with skeletal Class III malocclusion and OFCD syndrome was treated with edgewise appliance therapy combined with orthognathic surgery. We applied a light force during the treatment so as not to induce ankylosis. At the end of the surgical and orthodontic treatments, functional occlusion and an improved facial profile were achieved. After the retention period, stomatognathic function was improved. The results of this treatment suggest that surgical-orthodontic treatment is an effective method for improving skeletal disharmony, facial profile, occlusion, and stomatognathic function in patients with OFCD.

Influence of surgical orthodontic treatment on masticatory function in skeletal Class III patients

Skeletal Class III patients exhibit malocclusion characterised by Angle Class III and anterior crossbite, and their occlusion shows total or partially lateral crossbite of the posterior teeth. Most patients exhibit lower bite force and muscle activity than non-affected subjects. While orthognathic surgery may help improve masticatory function in these patients, its effects have not been fully elucidated. The aims of the study were to evaluate jaw movement and the electromyographic (EMG) activity of masticatory muscles before and after orthognathic treatment in skeletal Class III patients in comparison with control subjects with normal occlusion. Jaw movement variables and EMG data were recorded in 14 female patients with skeletal Class III malocclusion and 15 female controls with good occlusion. Significant changes in jaw movement, from a chopping to a grinding pattern, were observed after orthognathic treatment (closing angle P < 0.01; cycle width P < 0.01), rendering jaw movement in the patient group similar to that of the control group. However, the grinding pattern in the patient group was not as broad as that of controls. The activity indexes, indicating the relative contributions of the masseter and temporalis muscles (where a negative value corresponds to relatively more temporalis activity and vice versa) changed from negative to positive after treatment (P < 0.05), becoming similar to those of control subjects. Our findings suggest that orthognathic treatment in skeletal Class III patients improves the masticatory chewing pattern and muscle activity. However, the chewing pattern remains incomplete compared with controls.

Replacement of a first molar and 3 second molars by the mesial inclination of 4 impacted third molars in an adult with a Class II Division 1 malocclusion.

This case report presents the successful replacement of 1 first molar and 3 second molars by the mesial inclination of 4 impacted third molars. A woman, 23 years 6 months old, had a chief complaint of crowding of her anterior teeth and linguoclination of a second molar on the left side. The panoramic radiographic images showed that the maxillary and mandibular third molars on both sides were impacted. Root resorption on the distal surfaces of the maxillary second molars was suspected. The patient was given a diagnosis of Angle Class II Division 1 malocclusion with severe crowding of the anterior teeth and 4 impacted third molars. After we extracted the treated maxillary second premolars and the second molars on both sides, the treated mandibular second premolar and the second molar on the left side, and the root canal-filled mandibular first molar on the right side, the 4 impacted third molars were uprighted and formed part of the posterior functional occlusion. The total active treatment period was 39 months. The maxillary and mandibular third molars on both sides successfully replaced the first and second molars. The replacement of a damaged molar by an impacted third molar is a useful treatment option for using sound teeth.

Hesperidin potentiates ghrelin signaling.

Hesperidin, a flavanone glycoside consisting of the flavone hesperitin bound to the disaccharide rutinose, is found in highly nutritious foods, such as oranges, tangelos, tangerines, grapefruits, and other citrus fruits. Exogenous hesperidin has been shown to influence a wide variety of biological functions, including induction of apoptosis and suppression of proliferation in human cancer cells; inhibition of tumor development in various tissues; and expression of antibacterial, antiviral, and antifungal activities. Previous in vivo studies have revealed that hesperidin may play a role in ghrelin secretion from the stomach through antagonism of the serotonin receptors. Because ghrelin appears to be involved in the pathophysiological mechanisms of several human disorders, hesperidin could be a promising target for the treatment of various diseases. This review addresses studies focused on the orexigenic and prokinetic activities of hesperidin in the context of ghrelin secretion. This article also presents some promising patents of hesperidin.