W. Robert Hiatt

Restoration of mandibular continuity defects using combinations of hydroxylapatite and autogenous bone: Microscopic observations

The purpose of this investigation was to assess by light, transmission, and scanning electron microscopy the healing of mandibular continuity defects reconstructed with varying ratios of an alloplastic hydroxylapatite implant material (HA) mixed with autogenous bone (AB). This study reports the microscopic observations of implant and control sites at 6 and 18 months postsurgery. The results confirm the biocompatibility of dense HA granules. Specimens exhibited differing degrees of osseous regeneration that appeared related to the percent composition of HA. At 18 months, 86% and 91% of the HA granules were completely surrounded by bone in those specimens reconstructed with implants consisting of 25% and 50% HA, respectively. In contrast, specimens receiving implants consisting of 75% and 100% HA features osseous encapsulation of 75% and 66% of the granules, respectively. The results of this limited study indicate that dense HA granules mixed with AB in ratios ranging from 3:1 to 1:1 (AB:HA) may be successfully used as a bone extender during reconstructive surgery.

Congenital teratoid cyst of the floor of the mouth

Erich’ first used the term “dysontogenetic,” meaning disturbance in embryologic development, in referring to the origin of dermoid cysts of the floor of the mouth. Several mechanisms have since been reported in the literature concerning the embryologic basis for their occurrence. Eppley3 listed four mechanisms. These included: 1) submergence of ectodermal cells that were pinched off at the time of closure of the anterior neuropore; 2) entrapment of ectodermal rests during closure of the first and second branchial arches at the midline position; 3) remnants of the anterior tongue precursor, the tuberculum impar; and 4) misplacement of the adjacent embryologic tissues (i.e., foregut). The term dermoid cyst appears frequently in the literature and Meyer4 suggested retaining its use for all types of developmental cysts of the mouth floor. In a review of the literature, Eppley3 states that two types of congenital floor of the mouth cysts exist; the dermoid and heterotopic gastrointestinal cysts. Gorlin,’ in a review of the literature, described 13 cases of the choriostomatic cyst of gastric or intestinal epithelium. He theorized that mixtures of endodermal and ectodermal tissue could give rise to cysts containing both germ layers. Dermoid cysts of the floor of the mouth are rare but well-documented in the literature. Erich and New6 reported 1495 dermoid cysts. In this population, 103 (6.9%) were located in the head and neck. Twenty-five percent of the head and neck dermoids were present in the oral

Nutrition and the head and neck cancer patient

Patients with head and neck cancer have a unique nutritional problem that can affect their response to treatment. To properly manage these patients the oral and maxillofacial surgeon must be able to accurately assess their nutritional status and implement the proper metabolic treatment. This article reviews the benefits of nutritional support, the methods of patient assessment and nutritional repletion, and the advantages and disadvantages of the various alimentation modalities. Also, an analysis of the relationship of nutritional status and the surgical course of the head and neck cancer patient at our institution is presented.

Extubation criteria for oral and maxillofacial surgery patients

An overview is presented of some of the factors that should be considered before extubating a patient who has undergone an oral and maxillofacial surgical procedure. A discussion of the possible preoperative assessment of the patient, complications of intubation, effects of narcotics and muscle relaxants, assessment of airway edema, and criteria for extubation is included.

Short communication & case reportAmeloblastic fibrosarcoma

Ameloblastic fibrosarcoma is an extremely rare tumor. To date only 43 cases have been reported in the literature. An additional case of ameloblastic fibrosarcoma is presented; the clinicial features, histologic characteristics, treatment, and the relevance of the presence of dental hard tissue are discussed.

Mechanical behavior of mandibular continuity defects reconstructed using combinations of hydroxylapatite and autogenous bone

The purpose of this investigation was to determine the mechanical behavior of primate (Macaca mulatta) mandibles with continuity defects reconstructed using varying ratios of an alloplastic hydroxylapatite (HA) implant material mixed with autogenous bone (AB). The defects were allowed to heal for 6 and 18 months before killing the animals and mechanical testing. Each animal had one side of the mandible restored with 100% AB as control. The fracture strength and section modulus of the opposite side of the mandible, containing the test ratio of HA-AB, were directly compared with the mechanical behavior of the control side. The fracture strength and section modulus were evaluated by a cantilever type of mechanical test that took into account the anisotropic, viscoelastic, and geometric nature of the mandible. The type of bone and tissue at the fracture site was examined by scanning electron microscopy and a direct correlation between the amount of bone and/or fibrous tissue growth around the HA implant material and the fracture strength and section modulus values was established. The average fracture strength of the AB graft sites at 18 months was 9,975 +/- 4,300 psi, with ratios of 25:75 and 50:50 HA-AB giving test results approaching those of the AB graft sites.

Use of preformed hydroxylapatite blocks for grafting in genioplasty procedures

Dense hydroxylapatite is a synthetic, biocompatible, immunologically inert material that can establish a chemical union with bone when placed in intimate contact in histologic studies. The following is a preliminary report of the use of preformed dense, non-resorbable hydroxylapatite blocks as a grafting material for use in advancement and vertical lengthening of the bony chin associated with orthognathic surgical procedures. In rare instances where an autogenous bone graft would be required for vertical lengthening without any advancement of bony pogonion, the need is obviated by utilization of the hydroxylapatite solid block.

EQUAL OPPORTUNITIES FOR ALL

From the combination of knowledge and actions, someone can improve their skill and ability. It will lead them to live and work much better. This is why, the students, workers, or even employers should have reading habit for books. Any book will give certain knowledge to take all benefits. This is what this equal opportunities for all tells you. It will add more knowledge of you to life and work better. Try it and prove it.

Technique for rigid fixation of Le Fort and palatal fractures

Abstract In the surgical repair of Le Fort fractures, fixation is accomplished with either stainless steel wires or bone plates. In 10 patients treated during the last three years at Truman Medical Center, we found that the posterior lateral wall of the sinus, or buttress, had been severely comminuted, making such fixation difficult. With midpalatal fractures, which often accompany Le Fort fractures, palatal collapse and buccal torque of the segments are additional problems. Head frames can be used to maintain vertical dimension in the former cases, but a much simpler technique is available. A similar technique can also be used for midpalatal fractures.

Apertognathia: Its challenge and conquest: Report of a case

Apertognathia or open-bite deformity is the cause of poor speech, loss of masticatory function, and the resultant embarrassment of patients. The treatment of these malocclusions embodies the use of our own technical, scientific, and physiologic knowledge, coupled with the research of others. This article gives a solution to an unusual case and points out the present techniques and research are only building blocks for the future.