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Biomedical subjects

R G Pifer

Publications and source records attributed to R G Pifer.

7 recordsLinked to original sources
PubMed1999

Proposed cephalometric diagnosis for osteogenic obstructive sleep apnea (OSA): the mandibular/pharyngeal ratio.

The purpose of this laboratory study is to devise a simple, diagnostic test to assess possible osteological deficiency as a probable cause of OSA. Modern day skulls of fifty males and forty eight females of Tuscan origin and an additional seventy-five skulls, from India, with their cephalograms were used for this study. Mandibular length and antero-posterior dimension of the nasopharynx--pharyngeal tubercle (PhT) to posterior nasal spine (PNS)--were measured on the Tuscan skulls. The nasopharynx was similarly measured on the Indian skulls and readings multiplied by 1.14, the magnification factor of the cephalometric apparatus used. The PhT-PNS distance was then plotted on the cephalogram of Indian skulls with point PhT at the basiocciput. The possible presence of an osteogenic etiology of OSA can be determined by comparison of the mandibular/pharyngeal ratio obtained from the skull cephalograms to that of the individual patient.

Adolescent↗
PubMed1998

Interrelationships of brain, cranial base and mandible.

The purpose of this study is to evaluate the neural and masticatory growth factors that contribute to the development of the cranial base. Cephalometric and submentovertex (SMV) radiographs of 66 adult human skulls, of Caucasian (India) origin and unknown gender were used in this study. Results indicate that the cranial base, posterior to the foramen caecum, develops in response to brain growth. The part anterior to the foramen caecum develops in response to the mandible. Our findings indicate that: 1. the glabella instead of the nasion should be considered as the most anterior point of the cranial base. Mandibular dimensions (the height and the length) have a better correlation with CG than CN. 2. Instead of a single parameter, sella-nasion (SN), two parameters, the foramen caecum-glabella (CG) and the foramen caecum-sella (CS) should be considered. In cephalometry the more stable line CS, rather than SN, can be used for registration of successive radiographs; 3. The typical mandibular retrognathia, and/or the decrease in the posterior height (ascending ramus) of a Class II malocclusion could be explained by their positive correlation with SB (sella-basion) and the negative correlation with angle GSB.

Adult↗
PubMed1990

Evaluation of image quality in individual films of double film packets.

A total of 47 double film packets were exposed of a radiographic standard (step-wedge), a clinical model (dried skull), and a clinical situation (endodontic therapy). Dentists were employed as expert observers to compare detail and definition between front and back films within each packet. Front films (those closest to the source) had significantly superior image quality compared to back films (those further from the source). In vitro radiographic trials were significantly similar to in vivo radiographic results.

Chi-Square Distribution↗
PubMed1989

Bilateral bifid mandibular condyles. Report of three cases.

Bilateral bifid mandibular condyles are a rare anomaly that had previously been described only by Hrdlicka in material from skull collections. We present here three cases of bilateral bifid mandibular condyles in patients who sought treatment for other reasons. The radiographic appearance of this anomaly and its embryology are discussed.

Adult↗
PubMed1983

Transcranial radiographs in the evaluation of craniomandibular (TMJ) disorders.

To use a radiographic technique to evaluate patients, one must be aware of the limitations of the study. A TR can be used to show both structural and positional changes of the lateral third of the condyle and fossa. TR obtained at vertical angulations greater than 20 degrees will add significant distortion to the full open-mouth radiograph. The structural changes seen in the joints of patients with the TR who had further diagnostic studies were confirmed with tomography. The changes seen with tomography were either as severe or more extensive than those noted on the TR. Three patients who had extensive structural changes on both the condyle and fossa were shown by arthrography to have a perforation in the joint's soft tissues. While the lateral position of the condyle does not represent the entire joint, this study has shown that it may qualitatively serve as a positional indicator for the joint. The TR together with the rest of a patient's examination data can be used in the treatment. For the patient who has not responded to therapy or whose TR disagrees with the clinical examination, tomographic and arthrotomographic studies are suggested. In the group of 61 patients, 11 (18%) fell into this category. Further diagnostic studies were not felt to be necessary for the remaining 50 patients.

Diagnosis, Differential↗