Evaluation of protein undernourishment on the condylar process of the Wistar rat mandible correlation with insulin receptor expression

An assessment of masticatory efficiency and occlusal load distribution in adolescent patients undergoing orthodontic treatment with functional jaw orthopedics: A prospective cohort study

INTRODUCTION

Functional jaw orthopaedics, produces a radical change in the occlusal scheme and the masticatory apparatus, particularly in patients with Class II malocclusion. It remains to be seen how the changes brought about by a functional appliance alter the masticatory ability of a growing child, who needs the necessary nutrition to properly grow the craniofacial region.

MATERIALS AND METHODS

Pretreatment and Post-treatment values of masticatory efficiency and the distribution of the occlusal load at centric occlusion were evaluated and compared for 20 patients with Class II division 1 malocclusion undergoing functional jaw orthopaedics.

RESULTS

Significant increase in the masticatory efficiency was seen during and after treatment (p < 0.5) There was an increase in the anterior distribution of occlusal load associated with a concomitant decrease in the posterior region at centric occlusion.

CONCLUSION

Improvement in the masticatory efficiency was observed after treatment of a retrognathic mandible with functional jaw orthopaedics in the adolescent participants with Class II malocclusion. This highlights the importance of treatment with functional jaw orthopaedics, which apart from providing esthetic and functional improvement also improves the ability of a growing child to extract proper nutrition from his/her diet.

Intrauterine growth restriction affects bone mineral density of the mandible and the condyle in growing rats

OBJECTIVES

To investigate in growing rats the effect of intrauterine growth restriction (IUGR) on the bone mineral density of the mandible and tibia, as well as the quality of the mandibular and condylar bone.

METHODS

Twelve male rats were born IUGR by mothers sustaining 50% food restriction during pregnancy. Twelve control male rats were born by mothers fed ad libitum. Dual-energy X-ray absorptiometry (DEXA) of the tibia, proximal tibial metaphysis and the mandible, biochemical markers, histology and histomorphometrical analysis on the mandibular and subchondral bone of the condyle were performed.

RESULTS

IUGR significantly affected bone mineral density (BMD) of both tibial and mandibular bones. IUGR rats had significantly lower osteocalcin values (p=0.021) and phosphorus (p=0.028), but not 25-OH vitamin D (p=0.352). Bone area percentage in the mandible was significantly lower (51.21±5.54) in IUGR compared to controls (66.00±15.49), and for subchondral bone of the condyle for IUGR (47.01±6.82) compared to controls (68.27±13.37). IUGR had a significant reduction in the fibrous layer, but not the proliferating layer, with the hypertrophic layer significantly increased.

CONCLUSION

Maternal restricted nutrition during gestation can affect BMD of the mandible and the tibia of the offspring animals.

Effects of nutrition and hormones on functional appliance treatment outcome in patients with skeletal Class II malocclusion

BACKGROUND

Functional appliances has been used for treatment of skeletal Class II malocclusion for a long time; however, the real skeletal effects, mandibular growth particularly, remain insufficient. Several auxiliary approaches have been attempted with the hope of enhancing treatment effects. In this review, we summarize and discuss the use of additional nutrition and hormones to assist the functional appliance treatment on patients with skeletal Class II malocclusion.

METHODS

Relevant articles were identified by electronic research in MEDLINE Ovid using keywords such as "nutrition," "hormone," "functional appliance," "orthodontics," "maxillofacial development," and "maxillofacial abnormalities." References of related articles were assessed for relevant studies to identify additional published references.

RESULTS

The literature search yielded 239 studies. According to the current literature, use of additional nutrition and hormones, including growth hormones, sex hormones, insulin, and insulin-like growth factor I, seem to improve the effects of functional appliance treatment on patients with skeletal Class II malocclusion.

CONCLUSIONS

The current evidence indicates that additional nutrition or hormones might improve the treatment effects on mandibular hypoplasia compared with the functional appliance alone, which is a promising approach and calls for further studies.

Age-dependent changes of the mandible bone throughout the lifespan in female F344/N rat

Age-dependent changes of the mandible bone in female F344/N rats, aged 22-1196 days, were analyzed using physiological bone properties and morphology. Bone weight, bone area, bone mineral components, and bone mineral density were assessed using dual-energy X-ray absorptiometry. The bone weight, bone area, bone mineral components, and bone mineral density increased rapidly until approximately 150 days of age, increased gradually thereafter, and then stabilized or decreased after 910 days of age. The ratio of bone mineral components to bone weight (bone mineral ratio) increased rapidly until approximately 43 days of age and stabilized thereafter. Size of the mandible, which was measured at 13 points on mandible surface, increased with age, and the rate of change showed a similar pattern to the other parameters. From a principal component analysis on morphometric measurements, principal component 1 (size factor) increased proportionally with age, whereas principal component 2 (shape factor) decreased until approximately 88 days of age and then increased after 365 days of age. As a result, the scatter plots for principal component 1 and principal component 2 were V-shaped, which indicates that the mandible developed in size, with deformation at younger ages, and recovered its original shape later in life. Our results revealed the occurrence of inflection points at approximately 43, 88, 150, 365, and 910 days of age. Some of these ages corresponded to transition points revealed by the age-dependent changes of the occlusal mandibular condyle and tooth wear in the same rat.