Biomedical subjects
Publications and source records attributed to A J Cronin.
The aetiology of recurrent temporomandibular joint dislocation is numerous. A case is described of frequent dislocation which was finally treated using a carbon fibre sling. However this was removed 3 years later due to the presence of a radiolucency in the head of the condyle. Radiographic and photographic appearances of this carbon fibre induced radiolucency are shown.
In order to determine what effect the anterior cranial base has on the developing craniofacial skeleton, mechanical expansion of the growth of one segment of the anterior cranial base was performed. New Zealand white rabbits were used for this study. A sham-treated group (n = 16) underwent implantation of dental amalgam markers to either side of the frontonasal, coronal, and lambdoid sutures at 9 days of age to serve as markers of vault growth. The experimental group (n = 7) underwent the same marker placement at 9 days of age, but, in addition, at 30 days of age these animals underwent placement of a mechanical spring, unilaterally, at the frontosphenoid suture. A second control group (n = 8) underwent the same exposure of the frontosphenoid suture, but the spring was laid only on the surface of the bone. All animals were followed by radiographic cephalometry at 9, 30, 60, and 90 days of age. The experimental group demonstrated statistically significant expansion of the cranial base and ipsilateral coronal suture. The midface skeletal dimensions were unchanged by spring distraction of the cranial base. These findings indicate that cranial base sutural growth can be manipulated mechanically and that growth changes can be attained secondarily in the cranial vault skeleton.
Eosinophilic granuloma is a condition which may initially present with oral symptoms. Its variable oral clinical manifestations can result in a potential diagnostic problem for the dental surgeon. Two cases are presented which illustrate the difficulties in making a definitive diagnosis. The importance of a biopsy in diagnosis and the use of a whole-body skeletal scan in formulating a treatment plan are highlighted.
Craniofacial anomalies, such as Apert's and Crouzon's syndromes, are presumed to be related to premature growth arrest of cranial base growth sites. However, premature growth arrest at cranial vault sutures in animals appears to play a causative role in the development of cranial deformities characteristic of single-suture, or simple, craniosynostosis in humans. To study the possible causative role of cranial vault and other (interface) suture stenoses on the development of craniofacial deformity, a vault suture and an interface suture between the cranial vault and facial skeleton were simultaneously immobilized. Thirty-one New Zealand White rabbits at 9 days of age underwent implantation of dental amalgam growth markers adjacent to cranial vault and facial sutures. In the experimental group (n = 15), methylcyanoacrylate adhesive was applied over the coronal (vault) and frontonasal (interface suture between vault and facial skeleton) sutures to immobilize them. The remaining 16 animals served as sham-treated controls. All animals underwent serial radiographic cephalometry to document growth effects in the cranial vault, cranial base, and facial skeleton. Application of adhesive resulted in statistically significant (p less than 0.05) reduction in growth at the coronal and frontonasal sutures. This was accompanied by an overall significant reduction in neurocranial vault length during the first 30 days of development.(ABSTRACT TRUNCATED AT 250 WORDS)
Three techniques combining the shaping of calvarial and facial bone with onlay of methyl methacrylate are presented for use in the late treatment of unilateral coronal synostosis deformities. The procedures described are suggested as possible alternatives to extensive bone repositioning procedures. They have the advantage of being quicker and are therefore potentially safer operations. Acrylic is malleable and does not resorb; thus, permanent superior esthetic results may be achieved. The two most serious risks when using this technique are infection and limitation of growth. The risk of infection may be reduced by attaching the acrylic implant securely to surrounding bone, under sterile conditions, beneath well-vascularized skin. Growth limitation may be obviated by not placing acrylic across sutures in children with enlarging skulls.
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