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Biomedical subjects

E Ellis

Publications and source records attributed to E Ellis.

At least 127 records · Page 7Linked to original sources
PubMed1992

Growth of the mandible following replacement of the mandibular condyle with the sternal end of the clavicle: an experimental investigation in Macaca mulatta.

This study was designed to investigate the long-term effects of transplanted clavicles to the temporomandibular joint (TMJ) in juvenile monkeys. Sixteen juvenile female monkeys (Macaca mulatta) were used in this experiment. Eight animals were used as controls and were allowed to grow undisturbed for an 18-month period (group control). Eight animals were divided into two groups and underwent bilateral condylar excision via extraoral vertical ramus osteotomies. Four of these animals had their condylar segments removed and immediately replaced to serve as surgical controls (group condyle). The other four underwent condylar replacement with the sternal end of their clavicles (group SCJ). Standardized lateral cephalometric radiographs with the aid of tantalum bone markers were used to evaluate maxillary and mandibular growth. One-way analysis of variance (ANOVA) was used to determine the significance of differences between groups. All animals showed good mandibular function and a class I molar relationship following an 18-month evaluation period. Statistical analysis showed there was no significant difference in maxillary or mandibular growth between any of the three groups. The results of this investigation show that the sternal end of the clavicle may be a viable option in mandibular condylar transplant surgery.

Analysis of Variance↗
PubMed1992

A preliminary study of maximum voluntary bite force and jaw muscle efficiency in pre-orthognathic surgery patients.

The functional state of dentofacial deformity patients before orthognathic surgery has received relatively little study. In this study, the ability to generate occlusal force was compared between 84 patients before treatment for various dentofacial deformities and 57 controls. Maximal and submaximal bite forces were measured at the incisor and right and left first molar bite positions. Electromyographic activity (EMG) was recorded bilaterally from the anterior temporalis, posterior temporalis, and masseter muscles during each bite. An efficiency ratio was calculated for the jaw muscles by dividing the level of EMG by the occlusal force. There was a reduced ability to generate occlusal forces in the patients before surgery, especially among female patients. The reductions in maximal occlusal force were correlated with reduced efficiency of the jaw muscles.

Adult↗
PubMed1992

The effects of zygomatic complex fracture on masseteric muscle force.

The masseter muscle often has been implicated as a primary cause of postreduction displacement of the fractured zygomatic complex. However, this contention has never been proved. This study compared masseter muscle force in 10 male controls with that in 10 male patients who had sustained unilateral zygomaticomaxillary complex (ZMC) fractures. Calculation of muscle force was based on measured bite force, electromyogram, and radiographic determination of muscle vectors. It was found that the masseter muscle in patients with ZMC fractures developed significantly less force than masseter muscle in controls. Following fracture, the masseter force slowly increased, but at 4 weeks following surgery the majority of patients were still well below control levels. The results of this study cast uncertainty on the role of the masseter muscle in postreduction displacement of the fractured ZMC.

Adult↗
PubMed1992

A comparison of two methods for inserting lag screws.

This study compared the accuracy of two accepted methods of inserting lag screws. The ability of the two techniques to produce concentrically drilled holes between the inner and outer cortices, the ability to accurately overdrill a small hole, and the displacement of the cortices following application and tightening of the lag screw were investigated using an experimental model of bony cortices. The results indicate that when the gap between the cortices is large, both methods of lag screw insertion are equally inaccurate. For smaller gaps between the cortices, the drill guide technique is more accurate than the other.

Bone Screws↗
PubMed1992

A retrospective study of advancement genioplasty using a special bone plate.

This study evaluates skeletal stability and the remodeling process of the advanced genial segment when a single bone plate is used to stabilize the segment following osteotomy of the inferior border of the mandible. Thirty-nine patients with a minimum of 6 months follow-up who had advancement genioplasty stabilized with a Paulus chin plate were analyzed using cephalometrics and clinical examination. The results showed that stability of the result was excellent; pogonion maintained its immediate postsurgical horizontal position at longest follow-up. The remodeling pattern observed was similar to that reported in other studies using alternate forms of fixation in spite of the fact that the bone plate covered the areas where most remodeling occurs.

Adolescent↗
PubMed1992

Accuracy of face-bow transfer: effect on surgical prediction and postsurgical result.

One of the most common errors in model surgery for orthognathic surgery is in the mounting of the models on the articulator. This study assessed the ability of one type of face-bow to transfer the maxillary model to the articulator. Twenty-five consecutive mountings were evaluated by calculating the angle made between the maxillary occlusal plane on the cephalogram and comparing it with the maxillary occlusal plane angle on the articulator. An accurate face-bow transfer should transfer this angle, making the two similar. It was found that a significant difference between the maxillary occlusal plane angle on the cephalogram and the articulator was found in the average case. The implications of such errors and a technique to avoid them are presented.

Cephalometry↗
PubMed1992

Bone strain following application of a rigid bone plate: an in vitro study in human mandibles.

This study evaluated the effect of a bone plate on mandibular bone strain patterns during static loading. A stainless steel bone plate was unilaterally attached to five human mandibles, which were then subjected to static loads of 60 kiloponds. Four strain gauges attached to the cortical bone were used to measure the strain patterns within the mandible both before and after the bone plate was attached. The results showed that statistically significant alterations in the strain patterns occurred following plating of the mandible. The mandible with the plate attached became more stiff, presumably due to the difference in modulus of elasticity between the plate and the bone. However, this increase in stiffness was relatively small when compared with both total strain under load and strain produced by tightening of the bone screws.

Adult↗
PubMed1992

Rigid internal fixation for the treatment of infected mandibular fractures.

A review of the literature is presented that shows that treatment of infected fractures by rigid internal fixation is biologically sound. A protocol for managing infected mandibular fractures with plate and screw fixation was developed and used on 11 patients. All patients had osseous union of the fracture and none required removal of the bone plate. This protocol is recommended as a viable option in the treatment of infected mandibular fractures.

Abscess↗
PubMed1992

Peritoneal dialysis training in a patient with multiple congenital anomalies.

We report an adult patient with multiple congenital anomalies including absent right arm, short stature, and scoliosis who has been trained and successfully performs continuous cycling peritoneal dialysis independently. Motivated patients with end stage renal disease and various anomalies should be considered for peritoneal dialysis training.

Abnormalities, Multiple↗
PubMed1991

Effect of growth hormone on kidney growth and glomerular structure.

The effect of growth hormones (GH) on renal growth was measured in growing uremic rats using a five-sixths nephrectomy model and GH, 5 mg/kg per day. At the end of 8 weeks, somatic size was significantly smaller in the untreated uremic rats. The uremic rats given GH were the same size as the non-uremic control animals. Organ size (heart, liver and kidney) differed in that only untreated uremic animals had a significantly smaller kidney weight. Despite a five-sixths nephrectomy, the uremic animals receiving GH had kidneys the same size as sham-operated control animals. Renal function was not changed by GH therapy in either control or uremic animals. DNA content expressed as milligrams per kilogram kidney tissue was low only in the untreated uremic rats. Glomerular volume and proximal tubular area were elevated in both groups of uremic animals but were elevated to a significantly greater degree in those receiving GH. GH given in large doses to growing animals appears to induce both somatic and renal growth.

Animals↗
PubMed1991

Lag screw fixation of mandibular angle fractures.

This article presents a technique of applying lag screws for treating fractures of the mandibular angle. A review of 30 patients who had lag screws placed to treat such fractures showed that it is an extremely useful, but technique-sensitive, method of providing rigid internal fixation. The advantages and complications of this technique over bone-plate fixation are discussed.

Adolescent↗
PubMed1991

Lag screw fixation of anterior mandibular fractures.

A technique of applying lag screws for treating fractures of the anterior mandible is presented. A review of 41 patients who had lag screws placed to treat such fractures showed that it is a successful method of providing rigid internal fixation. The advantages of this technique over bone-plate fixation are discussed.

Adolescent↗