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This study was a histomorphometric comparison of the transmandibular implant (TMI) system and titanium implant using a confocal laser scanning microscope (CLSM). Two dogs were used. In each dog, 16 implant holes were made in the bilateral mandibular angle. Four cortical screws in the TMI, four titanium plasma spray (TPS) implants, and four hydroxyapatite (HA) coating implants were inserted and four holes were left as a control. Two dogs were sacrificed at 3 and 6 months. The samples were cut longitudinally and examined under CLSM. The contact rate of trabecular bone was smaller than that of cortical bone in all implants. The contact rates in TMI at 3 and 6 months was significantly smaller than those of TPS and HA and there was no difference between TPS and HA. Although the contact rate of TMI was low, only a small contact area may be enough for TMI because of its box form structure.

Finite element analysis (FEA) was used to study the influence of bony height and baseplate effect on the transmandibular implant (TMI). FEA was used to assess the stress distribution in the mandible, with and without a baseplate. Forces were applied to the center of a bar space. The von Mises stress (SEQV) was displayed in bone, and shear stress also was measured. Tensile stress was always seen at the so-called saddle area; compressive stress was seen at the inferior border. Tensile strain at the saddle area of a 6-mm height mandible is always 9.1 times greater (corresponding to more SEQV) than that of an 18-mm mandible. At same bone heights, saddle area stresses are similar with or without a baseplate. However, stress at the lateral transossseous post interface with bone was significantly different between different bone height groups. Shear stress around the lateral transossseous post was smaller than does the SEQV of the same site. Decreased bone height dramatically increases stress at the saddle area independent of the baseplate presence. These data suggest that bone apposition is found in the severely atrophic mandibles. Thus, there is no need for a baseplate in a slight to mild atrophic mandible.

Objectives : A clear understanding of the relationship between the micromechanical properties and orientation of the osteons within the mandible is important to understand mandibular function, fracture repair, treatment of temporo-mandibular joint disorders, the materials and organization of dental implants. The objective of this research was to obtain the micromechanical properties of human mandibular cortical bone as a function of orientation from TMJ to TMJ. Methods : A mandible obtained from a deceased 66 year-old female free of bone disease was used. The mandible was embedded in polymethylmethacrylate. The micromechanical properties analysis was obtained using the UH3 scanning acoustic microscope (SAM; Olympus Co., Tokyo, Japan). The coordinates system is defined such that the inferior border of mandibular is positioned on the x – y plane. x is along the anterior–posterior direction, y is in the horizontal direction and z is in superior–inferior direction. Results : The osteonal orientations were almost parallel to the x axis and eventually branched into two directions towards the coronoid process and condylar head. The SAM revealed that almost the whole area of the mandible body was found to be transversely isotropic in the plane perpendicular to the x axis. In the parallel and oblique directions, all data were transversely isotropic with respect to the x axis. Data of the perpendicular osteons were transversely isotropic with respect to the z axis. Significance : Having actual micromechanical properties as a function of orientation in the mandible could provide base line data for: fracture repair; choice of bone replacement materials.

In 1937, W.W. Eagle documented cases in which elongation of the styloid process (over 25 cm), or calcification of the stylohyoid ligament, appeared to be the cause of pharyngeal and cervical pain.1 The prevalence of an elongated styloid process is somewhat varied, although Fritz reports it as a common finding.2 Eagle believed that approximately 4% of the population had an elongated styloid process, and that only 4% of these persons showed symptoms.3 Kaufman et al4 radiographically found a 7.3% incidence of elongation in their sample, but no correlation to clinical symptoms was noted. Most cases are found in women, with an age distribution greater than 30 years of age.1,5,6 There are no data on the prevalence of an elongated styloid process in children. Eagle’s syndrome comprises symptoms that may include a dull, acing pain localized in either or both Received from the University Hospitals of Cleveland; Case Western Reserve University, Cleveland, OH. * Assistant Professor, Department of Oral and Maxillofacial Surgery. † Resident, Department of Oral & Maxillofacial Surgery. ‡ Chairman, Department of Otolaryngology/Head and Neck Surgery. § Chairman, Department of Oral & Maxillofacial Surgery. Address correspondence and reprint requests to Dr Quereshy: 2123 Abington Rd, Case Western Reserve University, Department of Oral and Maxillofacial Surgery, Cleveland, OH 44106. © 2001 American Association of Oral and Maxillofacial Surgeons 0278-2391/01/5901-0018$3.00/0 doi:10.1053/joms.2001.19302 94 EAGLE’S SYNDROME IN AN 11-YEAR-OLD PATIENT

This study used a cephalometric analysis that isolated tipping and bodily tooth movements of the upper and the lower incisors and measured vertical skeletal changes in the anterior region of the maxilla and mandible to evaluate the outcome of two-phase nonextraction treatment for open bite malocclusion. Twenty-nine subjects treated with an active vertical corrector (AVC) followed by fixed 022 orthodontic appliances were selected by one orthodontist from his private practice. All subjects lacked vertical incisor contact at the start of treatment and had adequate initial, end of phase 1, and deband lateral cephalograms. Each subject in the treated group was matched by age and sex with an untreated subject from the Broadbent Bolton Collection, Cleveland, OH. Data were collected for three time intervals; phase 1 treatment with the AVC (T1 to T2), phase 2 fixed-appliance treatment (T2 to T3), and over the total treatment period (T1 to T3). Analysis of the data showed no statistically significant (P < or = .002) changes between treated subjects and controls for any variables during the phase 1 (T1 to T2) or phase 2 (T2 to T3) treatment intervals. However, overbite was significantly improved compared with controls (P < or = .002) during the T1 to T3 time interval. It was concluded that two-phase treatment with the AVC followed by fixed orthodontic appliance treatment results in a statistically significant increase in incisor overbite. The observed increase in overbite was the result of small but clinically significant changes in relative mandibular vertical growth, bodily incisor movement toward the occlusal plane, and lingual tipping of the lower incisors.

Transmandibular implants (TMI) are indicated both for functional reconstruction of the severely atrophic mandible and when routine augmentation is unpredictable. This study investigates the interface of bone around a TMI, retrieved from the cadaver. The TMI had successfully functioned for 7 years. The mandible was immersed in 10% formaldehyde and sectioned into nine appropriate pieces. Samples were embedded in polymethylmethacrylate, and cut around the transosseous posts and cortical screws in both vertical and horizontal sections. Samples were analyzed at 400 MHz (nominal lateral resolution, 2.5 μm) using a UH3 Scanning Acoustic Microscope (Olympus, Tokyo, Japan). The middle of implant specimens 1–4 were cut to 50 μm, and stained by toluidine blue for light microscopy. Dental X-rays showed no bone resorption around any implant. On a 2-mm lateral scan, almost uniform interface space was seen between bone and implant surface in cortical screws. There are wider spaces around the transmandibular posts in the superior area. Histology revealed the small area of direct contact. There is bone marrow space in the interface, with no significant fibrous tissue. We interpret these results at the interface to be because of adaptation for stress distribution © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2006

The micromechanical elastic properties of potential bone-graft materials were compared with that of the human mandible. Six different potential bone-replacement materials were used: Bio-Oss (Osteohealth), OsteoGraf/N-700 (Ceramed), Pepgen P15 (Ceramed), Interpore200 (Interpore Cross International), Allogro (Ceramed), and Dynagraft (GenSci Dental). As a control, mandibular cortical bone was obtained from a 17-year-old woman. Micromechanical elastic property analysis was obtained with the use of a UH3 scanning acoustic microscope (Olympus Co., Tokyo, Japan) (SAM) at 400 MHz in the burst mode. Each sample was measured at three areas. The data were analyzed statistically by SPSS (SPSS, Inc.) with the use of the Student t test. In human bone, the reflection coefficients r of the x dimension (r = 0.75 ± 0.01) was statistically higher than those of the y (0.72 ± 0.05) and the z (0.72 ± 0.01) directions. The order of stiffness magnitude was found to be Pepgen (r = 0.73 ± 0.05) ≥ OsteoGraf (0.72 ± 0.03) > Bio-Oss (0.71 ± 0.02) > Interpore (0.69 ± 0.10) > Dynagraft (0.43 ± 0.05) > Allogro (0.36 ± 0.04). For these samples, Interpore alone showed a large deviation in properties in the same specimen. With regard to the elastic properties solely, bone-grafting materials made from bovine or processed marine coral appear to be reasonable choices as graft materials. © 2005 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 73B: 29–34, 2005

Micromechanical properties of human mandibular trabecular bone, with particular interest to any site differences were investigated. A mandible was harvested from a 66 year-old female cadaver free from bone disease. It was embedded in PMMA, cut into 2mm sections and polished. Micromechanical property measurements were obtained using the UH3 Scanning Acoustic Microscope (SAM) (Olympus Co., Tokyo, Japan) at 400MHz in the burst mode. 6 vertical slices from the right and 6 horizontal slices from the left were chosen. In each of the 12 samples, 3 points were measured; first in the center, the other 2 from the margins. Data were analyzed statistically by SPSS (SPSS, Inc.) using Student's t-test. The average value of reflection coefficient r is 0.58+/-0.079 with the range from 0.46 to 0.64; E=25.0+/-5.64 GPa. There is no significant difference in properties in the osteonal direction of related cortical bone and those found between the marginal area and center areas. The average value of r from the right side, 0.60+/-0.07, is statistically higher than the average value of from the left side, 0.56+/-0.07. Micromechanical properties of both mandibular trabecular and cortical bone have almost the same values.

Glucose-6-phosphate dehydrogenase (G-6-PD) deficiency is the most common human enzyme deficiency; an estimated 200 million people worldwide are affected by this enzymopathy.1 G-6-PD deficiency is an inherited disease characterized by hemolytic anemia caused by the inability to detoxify oxidizing agents. This X-linked enzyme disorder comprises a family of deficiencies caused by over 400 different mutations in the gene coding for G-6-PD.2 Only some of these mutations cause clinical symptoms. One possible benefit to having G-6-PD deficiency is that it confers a resistance to malaria. In G-6-PD–deficient persons, anemia is usually caused by certain oxidative drugs, infections, or fava beans. When any of these agents enter a red blood cell in a G-6-PD–deficient person, hemoglobin becomes denatured, thus destroying its function as the principal oxygen-carrying molecule. The following report describes a patient in whom a G-6-PD deficiency was recognized as a result of a maxillofacial infection.

Purpose In a prospective study, 146 consecutive transmandibular implant (TMI) patients were treated according to revised surgical and prosthetic protocols to induce and control bone growth. Revisions included 1) placement of transosseous posts and cortical screws between the mental foramina so that two threads extended beyond the alveolar crest of the mandible without protruding through the mucosa and 2) fabrication of an implant-borne prosthesis that rested on the retromolar pads with a gap of 2 mm between the denture base and the mucosal tissues in the saddle areas. Patients and Methods Measurements of the height of the mandible were made using a digital millimeter calliper and panoramic radiographs, with the enlargement calculated for each radiograph. The follow-up period ranged from 18 to 51 months. Results Bone growth was present in 131 of the 146 patients whereas the bone resorption was arrested in the remaining patients. Increase in bony apposition varied from 9 mm in patients with severe mandibular atrophy to 2 mm in patients with mild atrophy. Conclusion The revised surgical and prosthetic protocols for TMI insertion and rehabilitation are advocated to prevent further alveolar resorption and to promote bone growth in patients with mandibular atrophy.

The transmandibular implant has been designed to provide the patient with a severely atrophic mandible an implant that will bear the masticatory load. Thirteen edentulous patients treated with maxillary complete dentures and mandibular overdentures retained by the transmandibular implant were examined biannually for 2 years. Prosthodontic complications included the development of parafunctional habits, “combination syndrome”, and epulis in association with the mandibular denture. Surgery was necessary to control chronic mucosal irritation related to muscle pull in one patient. Among the soft tissue parameters, plaque index, gingival index, and sulcus depth demonstrated statistically significant correlations (Spearman). All patients reported an absence of discomfort and those with previous functional complaints reported the ability to masticate all foods. Patient response to overdenture reconstruction with the transmandibular implant seems to be similar to that observed with the combination case. Oral hygiene appears to be directly related to the soft tissue response.

Thirteen consecutive patients with complaints of dysfunction and pain associated with a mandibular denture were treated with the transmandibular implant. The implant was placed from a submental approach with an atraumatic surgical technique. No load was placed on the implant for 12 weeks. Patients were evaluated for pain, paresthesia, healing of the submental wound, soft tissue response, radiographic change, and mobility of the implant for a period of 2 years. Patient satisfaction was recorded at the 1- and 2-year examinations. The results demonstrate the reliability and reparability of the transmandibular implant system.