Effects of temporal muscle detachment and coronoidotomy on facial growth in young rats

Morphological variations of the condylar head among children aged 4-15 years: A panoramic study

BACKGROUND

Growth and development of dentocraniofacial complex occurs during various stage of development of dentition with TMJ as one of its centres of growth. The condition of temporomandibular joint can be visible from its condylar head form; therefore, it is crucial to recognize the normal morphology of condylar head during different stages of development of dentition.

AIMS

The aim of the study is to view the morphological appearance of condylar head during primary dentition, mixed dentition and permenant dentition.

SUBJECT AND METHODS

400 panoramic images of 194 boys and 296 girls were collected and were divided into three groups bases on the stage of dentition. Shape of the condylar head were determined by tracing the print out of the panoramic image on an X ray viewer.

RESULTS

The study showed that during primary dentition stage shape of the conylar head was dominated by round shape and as growth and development occurs the condylar head shape changes to convex.

CONCLUSION

The study describes the normal morphology of mandibular condyles in a child population attending The dentition status as well as growth of craniofacial has a significant role in determining condylar morphology.

Is Coronoidectomy Superior to Coronoidotomy for Improving Maximum Incisal Opening in Patients With Oral Submucous Fibrosis?

PURPOSE

In the management protocol of the oral submucous fibrosis (OSMF), multiple studies have advocated that an additional step of coronoidectomy or coronoidotomy helps achieve better and more consistent postoperative results. But, there are no studies that validate if one has an advantage over the other. This study aimed to compare the outcome of the coronoidectomy with coronoidotomy for OSMF cases.

METHODS

A randomized controlled trial was designed in patients with OSMF requiring operative intervention. Patients were randomized into 2 groups based on a computer-generated randomization table: group I coronoidectomy and group II coronoidotomy. The primary predictor variables were the 2 different adjunct surgical steps - coronoidectomy and coronoidotomy. The primary outcome variable was the postoperative maximum incisal opening (MIO). Secondary outcome variables were duration of surgery and blood loss.

RESULTS

The study sample was composed of 32 patients (16 each group). Both the groups were comparable in terms of demographic profile. The MIO after surgery was comparable throughout the study between the groups. Repeated measures analysis of variance for comparison of mouth opening within the group showed that there was a significant improvement in postoperative MIO in both the groups (group I P value <.001 and group II P value 0.004). A statistically significant difference was found in the duration of the surgery (3.5 ± 0.73 hours vs 2.06 ± 0.87 hours) and blood loss (393 .75 ± 278.6 mL vs 90.62 ± 58.36 mL) with the shorter time and less blood loss in coronoidotomy compared with coronoidectomy. All these cases were followed for 1 year.

CONCLUSIONS

Coronoidotomy as an adjunctive treatment in OSMF provides comparable treatment outcome in terms of MIO compared with coronoidectomy with the added advantage of shorter operating time and less blood loss.

nkx3.2 mutant zebrafish accommodate jaw joint loss through a phenocopy of the head shapes of Paleozoic jawless fish

The vertebrate jaw is a versatile feeding apparatus. To function, it requires a joint between the upper and lower jaws, so jaw joint defects are often highly disruptive and difficult to study. To describe the consequences of jaw joint dysfunction, we engineered two independent null alleles of a single jaw joint marker gene, nkx3.2, in zebrafish. These mutations caused zebrafish to become functionally jawless via fusion of the upper and lower jaw cartilages (ankylosis). Despite lacking jaw joints, nkx3.2 mutants survived to adulthood and accommodated this defect by: (a) having a remodeled skull with a fixed open gape, reduced snout and enlarged branchial region; and (b) performing ram feeding in the absence of jaw-generated suction. The late onset and broad extent of phenotypic changes in the mutants suggest that modifications to the skull are induced by functional agnathia, secondarily to nkx3.2 loss of function. Interestingly, nkx3.2 mutants superficially resemble ancient jawless vertebrates (anaspids and furcacaudiid thelodonts) in overall head shape. Because no homology exists in individual skull elements between these taxa, the adult nkx3.2 phenotype is not a reversal but rather a convergence due to similar functional requirements of feeding without moveable jaws. This remarkable analogy strongly suggests that jaw movements themselves dramatically influence the development of jawed vertebrate skulls. Thus, these mutants provide a unique model with which to: (a) investigate adaptive responses to perturbation in skeletal development; (b) re-evaluate evolutionarily inspired interpretations of phenocopies generated by gene knockdowns and knockouts; and (c) gain insight into feeding mechanics of the extinct agnathans.