Mineralized bone loss in partially edentulous trabeculae of ovariectomized rabbit mandibles.

OBJECTIVE: The purpose of this study was to evaluate trabeculae changes in partially edentulous bone in ovariectomized rabbits. BACKGROUND: Numerous clinical studies have suggested that the greater risk for oral bone loss in females may be correlated with osteoporosis after menopause. Knowledge of trabecular changes in partially edentulous bone in animals with loss of ovarian function may be beneficial in the diagnosis and treatment of partially edentulous patients of postmenopausal women. METHODS: Twelve adult female Japanese white rabbits were examined. The mandibular incisors were initially extracted to simulate the partially edentulous bone. Six animals were bilaterally ovariectomized and the other six sham-ovariectomized 12 weeks after tooth extraction. The partially edentulous parts of distal mandibular bodies were processed undecalcified 12 weeks after ovariectomized or sham-ovariectomized surgeries and examined by quantitative trabecular bone histomorphometry. RESULTS: In ovariectomized rabbits, there were significant increases in trabecular separation, osteoid volume, osteoid thickness, osteoid width, eroded surface, and mineral apposition rate, and a significant decrease in trabecular number. CONCLUSION: The results of sparser trabecular structure, more trabecular osteoid, and increased trabecular bone turnover demonstrate mineralized bone loss in partially edentulous trabeculae of ovariectomized rabbit mandibles and suggest that the same loss may occur in postmenopausal women.

Acoustic characteristics of sounds from temporomandibular joints with and without effusion: an MRI study.

Joint effusion has been associated with temporomandibular joint (TMJ) pain but can only be diagnosed by magnetic resonance imaging (MRI). For screening of patients with suspected effusion a simple and less expensive method would be desirable. We recorded joint sounds during jaw opening and closing movement from 34 TMJs with internal derangement (ID). Seventeen joints had joint effusion seen on MRI. Spectrograms of the sounds were displayed as waterfall plots showing profiles of the consecutive Hamming windows. If the profiles were similar, as judged by initial evaluation, the displayed pattern was classified as stable. If some profiles were distinctly deviating in their pattern, this was classified as unstable. Joints with effusion showed unstable sound pattern more often than joints without effusion (P < 0.001). It was concluded that TMJ sound analyses have a potential to identify joints with effusion based on their unstable sound pattern.

Bone mineral density in mandibles of ovariectomized rabbits.

The purpose of this study was to evaluate the association between loss of ovarian function and bone mineral density changes in the mandibles of ovariectomized rabbits using peripheral quantitative computed tomography. Twenty-four adult female Japanese white rabbits were used in this experiment. The mandibular incisors were initially extracted to create implant bone. Twelve animals were bilaterally ovariectomized and the other twelve sham-ovariectomized 12 weeks after tooth extraction. All rabbits were sacrificed at 4 and 12 weeks after ovariectomy and sham-ovariectomy, with 6 rabbits in each of the four resultant groups. The edentulous parts of distal mandibular bodies were measured by peripheral quantitative computed tomography. There were significant decreases in total bone mineral density and trabecular bone mineral density in the mandibles of rabbits at 12 weeks post-ovariectomy. The results demonstrate the mineralized bone loss in the mandibles of ovariectomized rabbits.

Perception of lateral misarticulation and its physical correlates.

In order to clarify the relationship between perceptual diagnosis of lateral misarticulation (LM) by sophisticated listeners and the physical correlates of LM, three experiments using sustained speech /integral/ were conducted. Experiment 1 was designed to compare the spectral envelopes of normal speech (NS) /integral/ with those of LM /integral/. Experiment 2 was designed to collect the auditory impressions of sophisticated listeners listening to LM and NS /integral/ with specific spectral envelope bands replaced by LM. These two experiments showed that: (1) the spectral envelopes of LM are flat or decrease along the frequency axis in the frequency band above approximately 4 kHz, and there is a substantial peak at around 3.2 kHz in LM, which varies peculiarly with time; (2) the replacement of the spectral envelope between 2.5 and 4.5 kHz of NS with that of LM resulted in a remarkable increase in auditory impressions of LM. The facts suggest that the spectral envelope characteristic of LM has a peculiar variation at around 3.2 kHz. Additionally, experiment 3 estimated the spectrum of sustained speech /integral/ using vocal tract area functions. The results suggest that typical peaks of LM are related to the length and position of the vocal tract constriction region.

The effects of transplantation of osteoblastic cells with bone morphogenetic protein (BMP)/carrier complex on bone repair.

We investigated the effects of transplantation of osteoblastic cells with a bone morphogenetic protein (BMP)/carrier complex on bone repair by in vitro and in vivo experiments. Poly-D,L-lactic-co-glycolic acid/gelatin sponge (PGS) was used as a carrier for cell transplantation. In the in vitro experiments, three cell types, C3H10T1/2 cells, MC3T3-E1 cells, and primary osteoblastic cells, isolated from newborn rat calvariae (ROB cells), were cultured for 2 weeks on PGS alone or PGS containing BMP-2 (PGS/BMP). C3H10T1/2 cells cultured on PGS/BMP expressed several markers related to differentiation of both osteoblasts and chondrocytes, such as alkaline phosphatase (ALP) activity and mRNAs for osteocalcin and aggrecan, whereas the cells cultured on PGS alone expressed no such markers. MC3T3-E1 cells cultured on PGS/BMP exhibited a more ALP-positive cells than those cultured on PGS alone. PGS/BMP promoted ROB cell differentiation into both osteoblasts and chondrocytes. In the in vivo experiments, we transplanted ROB cells, which had been cultured on PGS alone or PGS/BMP in vitro for 2 weeks, into bone defects created in rat calvariae. Transplantation of ROB cells cultured on PGS alone generated little new bone. Transplantation of ROB cells cultured on PGS, which absorbed a low dose (10 ng) of rhBMP-2,; induced significantly higher bone mineral content than PGS/BMP alone, although application of a high dose (1 microg) of rhBMP-2 induced no difference in bone mineral content between transplantation of PGS/BMP with or without ROB cells. These results show that transplantation of osteoblastic cells after induction of osteoblast maturation in vitro by cultivation on PGS/BMP is a potent technique for cell therapy of bone repair.

A histomorphometric study of the tissue reaction around hydroxyapatite implants irradiated after placement.

PURPOSE: The tissue reaction around hydroxyapatite (HA) implants irradiated at 3 different time points after placement was histologically and histomorphometrically analyzed to further determine the relation between irradiation and tissue reaction. MATERIALS AND METHODS: Cylindrical high-density HA implants were placed in the mandibles of 48 Japanese white rabbits. The mandible was then irradiated with a single 15-Gy dose 5, 14, or 28 days after implantation. The rabbits were sacrificed on days 7, 14, 28, or 90 after irradiation. Nonirradiated rabbits with implants were used as controls. Nondecalcified specimens stained with toluidine blue were used for histologic analysis and histomorphometric measurements. RESULTS: In the rabbits irradiated 5 days after implantation, the HA-bone contact occurred later than in the controls. The bone-implant contact surface ratio was lower than in the controls at each time of sacrifice because of necrosis of the newly formed bone just after irradiation. The HA-bone contact in rabbits irradiated 14 and 28 days after implantation was similar to that of the controls. Bone remodeling was suppressed in the rabbits in each group sacrificed 90 days after irradiation. CONCLUSIONS: Therapeutic irradiation shortly after implantation inhibits direct contact between the HA implant and the surrounding bone. Bone contact occurring before irradiation was minimally affected. Regardless of the interval between implantation and irradiation, postimplantation irradiation inevitably delays bone remodeling.

Effect of ovariectomy on bone remodeling adjacent to hydroxyapatite-coated implants in the tibia of mature rats.

PURPOSE: The purpose of this study was to examine the effects of estrogen deficiency on bone remodeling adjacent to implants in the tibia of mature rats. MATERIALS AND METHODS: Hydroxyapatite-coated implants were placed bilaterally in the proximal metaphysis of the tibia of 18 female Wistar rats (48 weeks old), and ovariectomy was performed 168 days later. As a control, sham ovariectomy was performed in a similar group of 18 rats. Six animals from each group were killed at 28, 84, and 168 days after ovariectomy. Undecalcified sections were prepared, and changes in the bone tissue around the implants were evaluated histologically. Histomorphometric measurements were made with a computer-based image analyzer to quantify the unit bone mass around each implant and the amount of implant-bone contact. RESULTS: In the cortical bone area, ovariectomy induced only a slight decrease in bone contact with the implant, compared with that in the sham-operated rats. However, both the bone volume around the implant and implant-bone contact were significantly decreased in the cancellous bone area in ovariectomized rats compared with the sham-operated rats. CONCLUSION: Thinning of the bone trabeculae holding dental implants may occur with estrogen deficiency.

Clinicoanatomic examination of the fibula: anatomic basis for dental implant placement.

The advantages of the free vascularized fibular flap include its ability to be shaped with relative ease and to be grafted at the same time tumors are resected, with consequent reduction in operation time. In addition, few complications occur at donor sites. However, a large, systematic, and detailed investigation of clinicoanatomic problems of the fibula has not been performed. Therefore, in the present study, the fibula was examined morphologically and morphometrically, with special attention to regions important in the placement of dental implants. Eighty fibulae obtained from cadavers of 41 Japanese individuals aged 46 to 92 years (mean, 72.7 years) were fixed with 70% alcohol after infusion of about 6 liters of 10% formalin via the femoral artery. Morphometric examination showed the nutrient foramen was located posteriorly in 85.0% of sections, the maximal width of fibular cross sections was 13.1 mm, and the maximal cortical thickness of fibular cross sections was 4.1 mm.

Bone reactions to titanium screw implants in ovariectomized animals.

OBJECTIVE: The purpose of this study was to investigate the reactions of bone tissue after the placement of implants into the tibiae of osteopenic model rats. STUDY DESIGN: Commercially pure titanium screw implants were placed in the bilateral proximal tibial metaphyses 168 days after ovariectomy had been performed on 12-week-old female Wistar rats. For control purposes, implants were similarly placed in sham-ovariectomy rats. The healing process was examined histologically by means of undecalcified sections at various intervals from 7 to 168 days after implantation. Through use of an automated imaging analytic system, changes in relative bone mass and implant-bone contact were histomorphometrically evaluated. RESULTS: In the cortical bone area, only a slight difference in bone contact was noted with the implant until 28 days after implantation. However, ovariectomy significantly affected bone contact at 56 days after implantation. The rate of bone contact in the cancellous bone area and the relative bone mass around the implant were significantly lower in the test group than in the control group. CONCLUSIONS: It is considered that a decrease in bone mass causes a reduction in the contact area between implant and bone and may also cause a reduction in the supporting ability of the implant because of thinning of the surrounding bone tissue.

Salivary gland aplasia with cleft lip and palate: a case report and review of the literature.

We report the case of a patient with lifelong symptoms of xerostomia and a repaired bilateral cleft lip and palate. The clinical evaluation demonstrated aplasia of the major salivary glands. A review of the literature pertaining to salivary gland aplasia is presented, along with a summary of the data regarding patient gender, defect sites, hereditary background, and combined manifestations. The diagnostic methods, possible pathogenesis, and management are also discussed.

Bone reactions around hydroxyapatite-coated implants in ovariectomized rats.

OBJECTIVE: The purpose of this study was to investigate bone reaction after implantation in an estrogen-deficient state by examining the changes in bone reactions within tissue surrounding implants in ovariectomized rats. STUDY DESIGN: Ninety-six 12-week-old female Wistar rats were used in the study; they were divided into 2 groups, an ovariectomized group and a sham-operated group. Hydroxyapatite-coated implants were placed in the proximal metaphyses of the tibiae 21 days after surgery. The tibiae were examined histologically by undecalcified sections at various intervals from 7 to 168 days after surgery. RESULTS: In the cortical bone area of the ovariectomized rats, the procedure did not induce any apparent changes in bone volume around the implant or in bone contact with the implant in comparison with the sham-operated rats. In contrast, both bone volume around the implant and contact of the implant with new bone were significantly decreased in the cancellous bone area in the ovariectomized rats in comparison with the sham-operated rats. CONCLUSIONS: Ovariectomy did not seriously affect bone healing after the placement of implants in cortical bone areas, but it reduced the bone contact ratio and the bone in the cancellous bone area.

Histomorphometric evaluation of the effect of hyperbaric oxygen treatment on healing around hydroxyapatite implants in irradiated rat bone.

The effect of hyperbaric oxygen (HBO) on the tissue reaction around hydroxyapatite (HA) implants in irradiated bone of rats was investigated. A single dose of 15 Gy was delivered to the right leg of 20 rats. HA implants were placed in the bilateral tibial proximal metaphysis 3 months after irradiation. HBO was administered to half of the rats before and after 15-Gy irradiation. The healing process was examined histologically and histomorphometrically. The results indicated that HBO slightly improved trabecular bone formation in the irradiated bone, accelerated bone remodeling in the nonirradiated bone, and improved HA-bone contact in both the irradiated and nonirradiated bones.

Amplitude and frequency spectrum of temporomandibular joint sounds from subjects with and without other signs/symptoms of temporomandibular disorders.

Temporomandibular joint (TMJ) sound is one of the most commonly recognized signs in patients with temporomandibular disorders (TMD) but is also frequently seen in asymptomatic individuals. Sound recording is therefore only meaningful if the sounds from a normal healthy joint can be differentiated from those in patients. In this study, the amplitude and power spectrum of the TMJ sounds from symptomatic patients and asymptomatic individuals were recorded and compared. The result showed that TMJ sounds from symptomatic patients had a larger amplitude than sounds from asymptomatic subjects. A significant proportion of sounds had frequencies between 2000 and 3000 Hz. It was concluded that the characteristic amplitude is worthy of further study as a sign of possible diagnostic value. Secondly, the bandwidth of the sensors used at electronic TMJ sound recording should not be less than 3000 Hz.

Anatomy of microvascular anastomosis in the neck.

Structural and morphometric investigations of the vessels of the neck region were carried out on 30 cadavers (15 male and 15 female in the age range of 45 to 93 years old) to gain more knowledge of the anatomy for microvascular surgery. Our results briefly are as follows: (1) The non-common-truck type of the external carotid artery (in which each branch arises separately from the external carotid artery) was found in 76.6 percent of cases, the truncus linguofacialis type was found in 21.7 percent, and the truncus thyrolingualis type was found in 1.7 percent. (2) The smallest internal diameter (the average was 1.2 mm) was found in the superficial cervical artery. (3) The largest internal diameter (4.4 mm) was measured in the external carotid artery. (4) The longest arterial section (127.8 mm) was measured between the clavicle and mandibular margin. This vascular section or stem consisted of three parts: the supraclavicular part of the common carotid artery, the proximal section of the external carotid artery, and the first 3 cm of the facial artery. (5) In 46.6 percent of cases, the facial, lingual, and superior thyroid veins joined together and formed a thyrolinguofacialis vein. (6) The type with one external jugular vein accounted for 83.0 percent of cases, and the type with one anterior jugular vein for 67.4 percent of cases. (7) The middle thyroid vein exhibited the smallest internal diameter (average of 2.0 mm). (8) The largest internal diameter (7.9 mm) was measured in the internal jugular vein. (9) The longest vessel to receive a vascular pedicle vein was the external jugular vein, the average length of which was 99.7 mm. (10) The frequency and location of valves in the facial vein were also determined.

Morphometric examination of the free scapular flap.

In this study we investigated the clinicoanatomic basis of the scapular flap by morphometric examinations of 42 cadavers. Our findings were as follows: With common-trunk type scapular vessels, the maximal lengths of arteries and veins that could be used for a flap pedicle were 93 and 91 mm. With direct-type scapular vessels, the maximal lengths were 95 and 71 mm. In common-trunk type vessels, the mean internal diameter 2 mm distal from the confluence of the scapular vessel was 2.8 mm for arteries and 3.3 mm for veins. In the direct-type vessels, the mean internal diameter 2 mm distal from the confluence of the circumflex scapular vessel was 1.8 mm for arteries and 3.3 mm for veins. The maximal superoinferior dimension of the scapular graft was 28 mm. The maximal lateral dimension of the scapular graft was 12 mm.

Tissue reaction around miniplates used for the fixation of vascularized iliac crest bone grafts.

MATERIAL/METHOD: In six miniature pigs revascularized autologous iliac crest bone grafts were fixed with two 2.0 mm titanium miniplates to a defined defect in the angle of the mandible. Tissue reaction around the implants was examined histologically and histomorphometrically at 2, 4, and 8 weeks after surgery. RESULTS: According to the evaluation of fluorescence microradiography, the cortical and medullary circulation and healing processes of bone in the vicinity of the implanted material were not disturbed after 2 weeks. At 4 weeks after surgery osseous healing occurred at the mandibula/graft interface. The histomorphometric results for the calculated percentage of direct bone/screw contact at 2 weeks were 24% with the grafted bone and 53% with the mandible. Intensive bone formation was observed in all parts of the graft by 4 weeks. The results of direct bone/screw. contact at 4 weeks were 56% and 64% and at 8 weeks 75% and 77% for the grafted and the mandibular bone, respectively. CONCLUSION: With 2.0 mm titanium miniplates used in the animal model, stable osteosynthesis and osseous healing was evident after 8 weeks of surgery. In addition, intensive remodeling of the transplanted bone without signs of creeping substitution was noted, and the bone/screw contact of the miniplate system increased with time.

Analysis of the articulation after glossectomy.

Rehabilitation of the oral cancer patient should aim to achieve not only morphological restoration but also post-operative functions. However, there are few reports describing quantitative evaluation of the latter. The authors have attempted quantitative evaluation of post-operative articulatory function after glossectomy, and report the evaluation of it by speech intelligibility, electropalatography (EPG), and acoustical analysis. Subjects were five directly sutured patients and five patients reconstructed with forearm flap, all after glossectomy. The target syllable was /ta/ from among speech intelligibility test samples. The speech intelligibility and acoustical analysis were investigated pre-operation, and 1,6 and 12 months post-operation. EPG data were collected by DP-01(RION) at 6 months post-operation. Acoustical analyses were carried out by consonant frequency characteristics and formant variance from consonant to vowel transitions. As a result, subjects reconstructed with a forearm flap showed higher restorative tendency than directly sutured subjects. Articulatory characteristics expected from acoustical analysis were more in agreement with the results of EPG than with the results of the speech intelligibility test. From the results, it was suggested that the acoustical analysis used for this research could reveal changes in articulatory movement and will be useful for quantitatively evaluating post-operative articulatory functions.

An anatomical study on the forearm vascular system.

The purpose of the present study was to establish the clinicoanatomical basis for the radial forearm flap. We conducted a morphometric investigation on 52 Japanese cadavers, of forearm vessels, for use in free forearm flaps. The mean inner diameter of the cephalic and median cubital veins at the interepicondylar line was 1.9 +/- 1.2 mm and 1.8 +/- 1.1 mm, respectively. Mean inner diameter of the radial artery and venae comitantes 1 cm distal to the origins of the radial and ulnar arteries was 2.3 +/- 0.5 mm and 1.6 +/- 0.5 mm, respectively. The longest segment of a superficial vein was 28.7 +/- 4.6 cm, it was measured between the basilic vein 5 cm proximal to the interepicondylar line and the cephalic vein at Lister's tubercle. The length of the radial artery was 18.1 +/- 1.7 cm. There were fewer valves in the basilic vein and cephalic vein proximal to the median cubital vein and in the brachial veins than in the distal antebrachial veins. From these results some of the clinicoanatomical considerations of forearm vessels which will form the clinicoanatomical basis of the free forearm flap should be clarified.