Growth in width of the head of the Macaca rhesus monkey as revealed by vital staining

Differential growth among components of the palate in rhesus monkeys (Macaca mulatta)

To understand the etiology of maxillary hypoplasia better, which is common in individuals with cleft palate and other craniofacial anomalies, the relative growth and contribution of the maxillary and palatine segments to enlargement of the hard palate was examined in rhesus monkeys. The purpose of the study was to identify and evaluate sites of differential growth of the palatine and maxillary segments as they contribute to the development of the midface and facial prognathism. One hundred and eight male and 107 female skulls ranging from 1.0 to 7.0 years of age were examined. Measurements of the maxillary and palatine lengths, palatal width, midface depth, canine length, and molar surface areas in the ontogenetic sample were collected. Univariate and bivariate statistics were used to describe dimensional changes and evaluate region-specific sex differences. The relative growth of palatal dimensions was evaluated using allometric analysis methods. Significant sex differences were observed (t-test, p < or = .05) for all palatal dimensions by 4 years of age. However, proportions of the maxillary and palatine segments to overall palate length appeared to be similar throughout growth for both sexes. The results suggest that sutures of the midface, in particular the transverse palatine suture, may be important in the bony development of the palate during growth. These sutures may contribute to the overall modulation of palatal development.(ABSTRACT TRUNCATED AT 250 WORDS)

Transversal maxillary growth in experimental submucous mid-palatal clefts. A roentgen-cephalometric study in the cat

At the average age of 2 1/2 months the mid-palatal suture and adjacent bone was extirpated in 24 domestic cats resulting in a 5 mm wide submucous cleft in the hard palate. In 16 other animals the corresponding mucoperiosteal flap was elevated and replaced without resection of the suture, i.e. testing the effect of the soft resection of the suture, i.e. testing the effect of the soft tissue trauma implied. Twenty-eight unoperated cats of corresponding age served as controls. The transversal maxillary growth was then studied radiographically by measuring the increase in distance, on cephalograms, between metallic implants inserted into both sides of the hard palate. Up to 50% reduction of transversal growth appeared where the mid-palatal suture had been extirpated. The palatal dimensions of the sham operated- and the unoperated groups did not diverge. The results obtained seem to indicate that growth in the mid-palatal suture is a combination of active growth due to proliferation of the sutural tissue, and passive growth induced by external forces exerting a traction in lateral direction.

Alterations in the upper facial growth of Macaca mulatta resulting from high-pull headgear

Four prepubertal Macaca mulatta monkeys, ranging in age from 13 to 24 months, were used in an investigation of the effects of high-pull headgear (to a face-bow) therapy on the growth of the upper facial skeleton. Amalgam bone implants were placed across the frontomaxillary, frontozygomatic, zygomaticomaxillary, and zygomaticotemporal sutures in each animal. Three of the monkeys wore appliances consisting of a maxillary dental spling, a face-bow, two coil springs, and an acrylic helmet. The fourth monkey (control) wore only a dental splint and a face-bow. A continuous high-pull headgear force of 300 grams per side was applied to the three monkeys for 81, 87 and 89 days, respectively, before death. Procion brilliant red 8-HBS vital stain was administered to all four animals at the start of and 3 days before the end of the treatment period. The facial growth patterns were determined from lateral cephalograms taken before and after treatment, from direct measurement of implant separation at the sutures, and from histologic sections of the four mentioned facial sutures.

Growth of the palate and maxillary dental arch

A histological study of rats using bone markers revealed sites and directions of growth of the maxillas.

Postnatal development of the rat mandible

The postnatal development of the anterior segment of the mandible was studied in the rat. A bar of cartilage was observed in the symphyseal region of a 1-day-old rat, which exhibited endochondral-like bone formation up to 21 days of age. Then the hyaline cartilage became transformed into fibrocartilage, which persisted in the midline of the adult rat mandible.