Displacement and stress distribution in the temporomandibular joint during clenching

The aim of this study was to analyze biomechanical reactions in the mandible and TMJ during clenching under various restraint conditions. A three-dimensional finite element model of the mandible, including the TMJ, was created for test purposes. The results were as follows: (1) Under any restraint conditions, displacement was greatest on the surface of the condyle and less on the articular disc and the surface of the glenoid fossa, in that order. Resultant stresses followed the same trend. (2) Displacement and stress were greatest when the lower central incisor was restrained and attenuated as the posterior teeth were restrained. Because the biomechanical reaction of the TMJ during clenching was greatest when the lower central incisor was restrained, premature contact of these teeth may be one of the factors involved in the initiation of temporomandibular arthrosis.

Cephalometric changes during self-correction of primary anterior crossbite

Longitudinal growth changes were investigated cephalometrically for sixty-one Japanese girls who had anterior crossbite at the initial visit (ages 3 years and 11 months on an average). Cephalograms were taken annually from the initial visit to the end of the observation period (ages 7 years 6 months on an average). Eleven of them (Group N1) showed self-correction of anterior crossbite during the primary dentition; ten (Group N2) showed self-correction when the permanent incisors erupted and forty (Group R) did not show self-correction. There was no statistical skeletal difference between Groups N1 and N2 during the observation period. Groups N1 and N2 were larger, however, than Group R in A'-Ptm'/Pog'-Go (p < 0.05) and Group N1 was smaller than Group R in Pog'-Go/N-S (p < 0.01) at the end of the observation period. In summary, favorable growth of the maxilla relative to the mandible leads to self-correction of primary crossbite and when mandible size relative to the cranial base is large, primary crossbite does not show self-correction.

Three year prospective, randomized evaluation of intraocular lens implantation through 3.2 and 5.5 mm incisions

PURPOSE

To compare the long-term clinical results of two small incision cataract surgery procedures.

SETTING

Seven centers in Japan.

METHODS

Two hundred eyes were randomly assigned to receive a silicone intraocular lens (IOL) through a 3.2 mm incision or a poly(methyl methacrylate) (PMMA) IOL through a 5.5 mm incision. Except for incision size and implantation technique, the surgical methods were identical. Uncorrected and corrected visual acuity, keratometry, flare-cell intensity, specular microscopy, and neodymium:YAG (Nd:YAG) laser posterior capsulotomy rate were analyzed up to 3 years after surgery.

RESULTS

Eyes in the 3.2 mm incision group had significantly better uncorrected and corrected visual acuity in the early postoperative period and lower aqueous flare intensity immediately after surgery, but these differences disappeared after the first postoperative month. However, surgically induced astigmatism was significantly less in the 3.2 mm incision group than in the 5.5 incision group throughout the study. The Nd:YAG laser capsulotomy rate was higher in the silicone IOL group (23.5% at 3 years postoperatively) than in the PMMA IOL group (18.4%) but the difference was not statistically significant.

CONCLUSION

Smaller incision cataract surgery led to early recovery of visual function in the short term and less induced astigmatism in the long term.

Three-dimensional computed tomography evaluation of postsurgical condylar displacement after mandibular osteotomy

OBJECTIVE

The purpose of this study was to examine both condylar displacement of the temporomandibular joint after sagittal split ramus osteotomy with rigid osteosynthesis and intraoral vertical ramus osteotomy without osteosynthesis in patients with mandibular prognathism by means of three-dimensional computed tomography.

STUDY DESIGN

In this pilot study, five patients treated with sagittal split ramus osteotomy and 5 patients treated with intraoral vertical ramus osteotomy were evaluated. A technique to superimpose a postoperative three-dimensional computed tomography image on its corresponding preoperative image was designed. Postoperative condylar displacement, rotation, and tilting were measured in three-dimensional computed tomography images.

RESULTS

Within 3 to 6 months after surgery, changes in the inclination of the condylar axes were distinctly seen, although changes in the position of the condyles within the joints were minimal. In particular, outward rotation of the condylar long axes after intraoral vertical ramus osteotomy was a frequent finding.

CONCLUSIONS

The three-dimensional computed tomography superimposition technique was a practical method of evaluating postsurgical condylar displacement after mandibular osteotomy.

Longitudinal changes in the skeletal pattern of deciduous anterior crossbite

Some patients who have an anterior crossbite in the deciduous dentition lose the crossbite during the transitional stage to permanent anterior teeth without orthodontic and/or orthopedic treatment. We observed 220 anterior crossbite patients at regular intervals and identified three groups of patients: in group N (n = 16) the crossbite corrected when the central incisors erupted; in group R1 (n = 16) the crossbite was within [formula: see text] and remained unchanged following the eruption of the permanent central incisors; in group R2 (n = 12) the crossbite extended over [formula: see text] and remained following the eruption of the permanent central incisors. The purpose of this study was to determine whether any differences existed among the above three groups at the initial examination, or if differences arose during eruption of the teeth. The findings indicate that the mandibular position in group N was more posterior than in groups R1 and R2, and the lengths of Pog'-Go and Gn-Cd in group N were smaller. Tooth axis of the lower incisors in groups R1 and R2 showed lingual tipping, and the maxilla in group R2 was underdeveloped. The findings of the longitudinal changes indicated that the maxillary length in group N increased and mandibular forward growth was suppressed. The initial maxillary position in groups R1 and R2 remained much the same until the permanent central incisors erupted.

Orthodontic treatment of an open bite patient with oral-facial-digital syndrome

A case of oral-facial-digital syndrome was treated orthodontically. Characteristics of this case were mandibular protrusion with open bite. Occlusal stability after correction of this malocclusion was achieved with the uprighting of the posterior teeth, surgical reduction of the enlarged tonsils and highly attached tongue frenum, and oral functional training.

Tenascin: growth and adhesion modulation--extracellular matrix degrading function: an in vitro study

Tenascin (TN), a recently characterised extracellular matrix protein, largely confined to the process with the development of embryo in areas of epithelial-mesenchymal interactions and in areas where there are morphogenetic movements and tissue patterning, has a highly restricted expression in adult tissues. The expression of TN is enhanced in a variety of human neoplastic lesions. However, function(s) and molecular mechanisms of enhanced expression in neoplastic lesions remain unclear. We employed human tongue carcinoma cells (SCCKN), human salivary gland adenocarcinoma cells (SGT-1), normal mouse embryonic fibroblasts (NIH3T3-3) and K-ras-2 transformed fibroblasts (Cle-H3) in an in vitro study to elucidate the biological roles of TN. In in vitro studies, all the cell lines examined had enhanced secretion of TN in the presence of transforming growth factor-beta in a dose-dependent manner and TN itself was found to possess a growth-enhancing activity. Moreover, studies on adhesion of the cell lines on coated substrates of fibronectin (FN), laminin (LN), tenascin (TN), TN/FN and TN/LN showed that all the cells adhere and spread well on FN and LN. However, on TN they attach poorly and remain rounded. The relative concentrations of TN and FN affected the cellular adhesion and morphology. In SCCKN and SGT-1, but not in NIH3T3 and Cle-He3 fibroblasts, a higher concentration of TN inhibited cellular adhesion on fibronectin, suggesting that cells attach poorly on TN, it may interfere with the action of fibronectin, and the relative concentrations of TN, FN or LN may affect cellular adhesion and morphology which may differ in different cell types. When TN was added in the growth medium of exponentially growing cells, the cells lost their cell to cell contact and were seen to be separating. The presence of these extracellular matrix proteins were further tested to determine whether they could modulate the secretion of proteolytic enzymes responsible for extracellular matrix degradation by tumour cells, when the neoplastic cells but not the non-neoplastic cells grown on FN/TN substrate showed positive immunofluorescence for collagenase. FN, LN or TN alone did not induce collagenase in the tumour cells. If the same is true in vivo, although a number of factors and interactions may implicate the ultimate outcome, the enhanced expression of TN in neoplastic lesions may have potential implications for tumour growth, differentiation, cellular adhesion, invasion and metastasis.

Stimulation of in vivo calcification using collagen membranes cultured with osteoblastic cells in vitro: a preliminary report

Guided tissue regeneration (GTR) is a useful modality in the management of periodontal disease and for bone augmentation around osseointegrated implants. This study evaluated the in vivo use of atelocollagen membrane (AC) on which osteoblastic cells (OBCs) were cultured in vitro, for application as a GTR membranous material. Osteoblastic cells isolated in our laboratory from mouse calvaria formed a thin film on the AC in vitro which was easily manipulated after 21 days in culture. The AC and OBCs complex material (ACOB) was subjected to freezing and thawing and implanted in mouse subcutaneous tissue for the study of histologic events surrounding the implanted ACOB. Histologic findings in the subcutaneous tissue showed calcification on the ACOB at 28 days postimplantation, while no such finding was evident at the control site, where only AC without OBCs were grafted. The present study suggests the possibility of membrane calcification for GTR through ACOB produced by OBCs on an AC in vitro.

Posterior bite raising effects on a primary anterior crossbite case

Stainless steel crowns were cemented on the mandibular primary molars to make bite raising for an anterior reversed bite case. Chewing force and MKG were recorded before and after bite raising. Data from MKG revealed that co-ordination pattern of muscle activities after bite raising became higher in masseter muscles than those before anterior reversed bite was corrected easily without any incisal interferences by using this treatment method.

Allotransplantation of cryopreserved menisci in monkey: histological change

The purpose of this study was to carry out a histological evaluation of cryopreserved menisci used as allografts in monkeys. Menisci were evaluated histologically at one, three, six and at twelve months after transplantation. In the deep layer of the allografts, the number of cells and the amount of the extracellular matrix had decreased at three to six months after transplantation. After twelve months, the evaluation revealed that both the cell counts and the extracellular matrix had increased returning to nearly normal levels. However, the colour of the matrix stained with Masson's trichrome had changed to red. This change may correspond with the occurrence that of young newly-formed collagen. Since the articular cartilage showed minimal degenerative change, it is concluded that meniscal transplantation is useful and should be considered for meniscal injuries.

Comparative study of intraocular lens implantation through 3.2- and 5.5-mm incisions

PURPOSE

To prospectively and comprehensively compare the clinical results of two small-incision cataract surgery procedures, silicone intraocular lens (refractive index of 1.46) implantation through a 3.2-mm incision and polymethylmethacrylate intraocular lens implantation through a 5.5-mm incision.

METHODS

Two hundred eyes with cataract randomly were assigned to either procedure. Except for incision size, identical surgical methods were used in every case. Data on uncorrected and corrected visual acuity, keratometry, corneal topography, flare-cell measurement, fluorophotometry, specular microscopy, glare disability measurement, and photographic examination of intraocular lens decentration were analyzed up to 6 months after surgery.

RESULTS

Eyes in the 3.2-mm incision group displayed significantly better uncorrected and corrected visual acuity in the early postoperative period, lower aqueous flare intensity and cell counts immediately after surgery, less operatively induced astigmatism throughout the study period, and less corneal topographic changes taken 3 months after surgery. No significant between-group differences were noted for other parameters. Complications in the two groups were few and comparable.

CONCLUSION

Both procedures of small-incision cataract surgery offered satisfactory clinical results, but 3.2-mm incision cataract surgery allowed significantly earlier recovery of visual function and better preservation of corneal shape.

Multiple symmetrical lipomatosis: no longer just a Mediterranean disease?

Multiple symmetrical lipomatosis is a rare condition, of which the etiology remains unclear. Most reported cases have been from the Mediterranean countries, and it is generally thought of as a disorder characteristic of that region. However, there have been 11 cases reported in Japan since 1978, suggesting that this condition is no longer confined to Mediterranean countries.

An in vivo evaluation of an osteoinductive implantable material produced by osteoblastic cells in vitro

Osteoinductive implantable materials have been a subject of basic science research in clinical implantology. This study examined the osteoinductive effect of an implantable material produced by osteoblastic cells that were isolated in the laboratory from mouse calvaria. After 21 days in culture, osteoblastic cells formed a thin film that could be easily manipulated. This thin film was subjected to freezing and thawing and was implanted in mouse muscle tissue. Osteoblastic cells were strongly positive for alkaline phosphatase reactivity and Von Kossa stain in vitro. Collagen type I, osteocalcin (BGP), and alkaline phosphatase were identified at the immunohistochemical electron microscopic level. Histologic findings showed an osteoinductive effect of the implanted material. The results strongly suggest the possibility of producing an osteoinductive implantable material by culturing osteoblastic cells in vitro.

Effects of OK-432 on in vitro secondary responses of the non-adherent cells to IL-2 and OK-432 in cancer patients without tumor burden

We examined the effect of OK-432 intracutaneous injection on the in vitro responses of non-adherent cells to IL-2 and OK-432, along with changes in lymphocyte subpopulations, in early cancer patients who underwent surgery. We found that 1) repeated injections of OK-432 resulted in an enhancement of LAK activity, the peak of which was seen between 7 and 10 days after the first administration, 2) this augmentation of LAK activity was not associated with changes in lymphocyte subpopulations CD8+ CD11- and CD8+ CD11+ phenotypes, and 3) the cytotoxic activity of lymphocytes stimulated in vitro with OK-432 did not show a definite change in specific pattern after in vitro OK-432 treatment. These findings indicate that repeated injections of OK-432 over a period of a week effectively enhanced LAK activity.

Effect of OK-432 on cytotoxic activity in cancer patients without tumor burden

The present study was designed to determine the optimal therapeutic protocol for OK-432, a streptococcal preparation, and to clarify the kinetics of various immunological parameters following intracutaneous administration of OK-432 in 39 disease-free postoperative patients with early cancer. These patients were randomly divided into 4 groups according to the dose (1KE or 5KE) and the frequency of administration (one or 3 times every other day) of OK-432. NK activity 3-4 days after the first injection increased significantly in patients whose pretreatment baseline activity was below the lower level of normal values (60 LU) in all study groups (P < 0.05). The elevation of post-therapeutic NK activity lasted for 2 weeks in the group of patients given repeated injections. The serum content of cytotoxic activity against L-M cells increased significantly after the injection of OK-432 at doses of more than 5 KE doses (p < 0.05). These findings suggest that repeated injections of OK-432 over a period of a week have important immunotherapeutic results.

[Orthodontic treatment of adults with periodontal disease]

Orthodontic treatment has diversified in recent years along with progress in other dental specialties. Adult orthodontic treatment has become more popular as patients appreciate the need for a higher level of oral health accompanied with progress in orthodontic objectives and treatment methods. At the same time, patients with periodontal disease in number every year. Recently, two adult females with periodontal disease, one with crowding (20 y 1 m at her initial visit) and the other with bimaxillary protrusion (34 y 9 m at her initial visit), obtained good occlusion and periodontal health through orthodontic treatment. As a result of free mandibular movement by applied mild orthodontic forces and balanced occlusion, infrabony defects improved to achieve a higher level of the alveolar crest.

Pathologic and enzyme histochemical studies on bone formation induced by bone morphogenetic protein in mouse muscle tissue

Bone morphogenetic protein (BMP) irreversibly induced the differentiation of mesenchymal-type cells into osteoprogenitor cells for endochondral ossification. During the process of BMP-induced differentiation in mice, 4 cell type (chondroblasts, osteoblasts, chondroclasts, and osteoclasts) were examined for phosphatase and succinate dehydrogenase using a wide range of buffers (4.0 less than or equal to pH less than or equal to 9.2). During the chondroid tissue-forming stage (1 week), chondroblast-like or osteoblast-like cells expressed phosphatase activity at 6.8 less than or equal to pH less than or equal to 9.2; chondroclast-like or osteoclast-like cells expressed phosphatase activity at 4.0 less than or equal to pH less than or equal to 5.8. However, mature chondrocytes found in hyaline cartilage expressed phosphatase activity between 6.6 less than or equal to pH less than or equal to 7.6 (2 weeks). During the process of endochondral ossification, alkaline phosphatase activity decreased in osteoblast-like cells with traces of acid phosphatase activity still detectable. Chondroclastic and osteoclastic giant cells were characterized by intense succinate dehydrogenase activity.

Thiazolo[4,5-d]pyrimidine nucleosides. The synthesis of certain 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidines as potential immunotherapeutic agents

Novel analogues of the naturally occurring purine nucleosides were synthesized in the thiazolo[4,5-d]pyrimidine ring system to determine the immunomodulatory effects of insertion of a sulfur atom in place of nitrogen at position 7 of the purine ring. In particular, 5-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H) -dione (7, guanosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,5,7(3H,4H,6H) trione (8, xanthosine analogue), 3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidine-2,7(3H,6H)-dione (10, inosine analogue), and 7-amino-3-beta-D-ribofuranosylthiazolo[4,5-d]pyrimidin-2(3H)-one (32, adenosine analogue) were prepared, as well as the 8-mercaptoguanosine (14) and 6-mercaptoguanosine (17) analogues. Single-crystal X-ray studies confirmed the structural assignment of 17 and 32 as having the beta-configuration with the site of glycosylation at N3. The nucleosides were evaluated for their ability to potentiate various murine immune functions in direct comparison to the known active agents 8-bromoguanosine (1), 8-mercaptoguanosine (2), and 7-methyl-8-oxoguanosine (3). Two of the guanosine analogues, 7 and 14, were found to exhibit significant immunoactivity relative to the positive control compounds (1-3), while the adenosine, inosine, xanthosine, and 6-mercaptoguanosine analogues were devoid of activity. Compound 7 exhibited greater immunoactivity than any of the other guanosine analogues and derivatives in all test systems. Specifically, 7 was shown to be about twice as potent as 3 in the murine spleen cell mitogenicity assay. In addition, treatment with 7 produced about a 4-fold increase in natural killer cell cytotoxicity, while treatment with 3 afforded a 3-fold increase over controls. Finally, 7 provided excellent protection (92% survivors compared to 0% for placebo controls) against Semliki Forest virus in mice. Induction of interferon may account for the major mode of action of these guanosine analogues.

[Automatic boundary detection and pathological diagnosis of the maxillary sinus]

A method for automatic boundary detection of the maxillary sinus from a cranial X-ray radiograph has been developed. An algorithm using the local segmental properties of the X-ray image to transform a continuous tone image into a bi-level image is introduced. In addition, the global shape information such as the area, the perimeter, and the complexity, are considered for the boundary detection. The boundary of the maxillary sinus detected by this method coincided precisely with the area plotted-by experienced otolaryngologists. Furthermore, the cumulative distribution function (CDF) calculated from the density histogram of the maxillary sinus has been employed to perform the tonal evaluation of the intra-maxillary pathological changes. The distance between the CDFs successfully demonstrated the difference in pathological stages of the chronic sinusitis.

[A case of carcinoma of the ileum diagnosed as an adenocarcinoma]

A 65-year-old female with a history of cancer of the uterine body and a strong family history of cancer, was admitted with abdominal pain and anemia. During roentgenographic examination of the small intestine, a tumor was recognized about 25 cm from the ileocecal valve, leading us to suspect a carcinoma of the ileum. A colonoscopy demonstrated a constricting, ulcerated lesion, with a round wall: and a subsequent biopsy proved that the patient had a moderately differentiated adenocarcinoma. At surgery, a tumor, measuring 52 x 50 mm, was found to have infiltrated the serosa with a metastasis to the mesenteric lymph node.

A case of the pathogenesis of choledochocele in relation to dysfunction of the sphincter of Oddi

A 47-year-old woman was admitted for evaluation of pain in the right upper quadrant of the abdomen. Seventeen years previously, she had undergone cholecystectomy for cholelithiasis. Endoscopic retrograde cholangiopancreatography (ERCP) showed a cystic dilatation of the terminal portion of the common bile duct (CBD) protruding into the duodenal lumen and delaying the drainage of contrast medium. In this patient the CBD and the pancreatic duct appeared to be unimportant in the formation of the cyst. Repeated changes in the radius of the cyst suggested dysfunction of the ampullary component of the sphincter of Oddi, with maintenance of normal function of the common duct component. The pathogenesis of the choledochocele in this patient is discussed in relation to dysfunction of the sphincter of Oddi. In addition, 2 criteria for the diagnosis of choledochocele by ERCP are proposed: [1] cystic dilatation of the terminal portion of the CBD protruding into the duodenal lumen, and [2] absence of the narrow segment of the CBD.

[Longitudinal changes in the dentition of the deciduous reversed bite using plaster casts]

It is known that some of the deciduous reversed bite cases are corrected spontaneously by themselves. No decisive conclusion, however, has been achieved so far as to what morphological characteristics the self corrected cases have. The purpose of this study, therefore, was to determine whether the difference between the self corrected group (n) and the non-self corrected group (r) exists at their initial examination or if it occurs as a result of changes in occlusion. The materials used in this study were the serial plaster casts of 29 Japanese girls with the deciduous reversed bite at their first visit and these were measured with the three dimensional measurement system. The following results were obtained: 1. Characteristics of the initial examination with the n group: Overjet (-) and overbite in the n group were smaller than in the r group. The arch length and the perimeter of the maxillary dentition in the n group were longer, and the area of the incisive bone (U-C) was wider than in the r group. Moreover, the upper and lower canines in almost all of the n group cases were not touching each other and did not restrict mandibular movement, resulting in easy attrition for the deciduous anterior dentition. 2. Longitudinal changes in the n group: Mean change of this group showed a decrease in overbite caused by the attrition of the deciduous central incisors and the continuous eruption of the maxillary second deciduous molars. Overjet also decreased, because of an increase in the maxillary anterior arch length and of backward movement in the mandibular dental arch. Individual changes were much alike in mean changes in almost all of the measured items. Arch width between canines in the maxilla and arch length in the mandible decreased in some cases, suggesting that a discrepancy would occur when the permanent incisors erupt. 3. Longitudinal changes of the r group: Mean changes showed that overbite decreased in the same pattern as the n group, but overjet did not change and the mandible did not show backward movement. The reason was that overbite in this group was deeper than in the n group at the initial examination. Moreover, deciduous molar to molar width became wider to compensate the decrease in the arch length and the perimeter. Individual changes showed that some of the r group cases had a tendency to improve, but some became worse.

Gas permeability of round window membrane

The perilymphatic oxygen tension in the scala tympani was measured with a polarographic technique after various gases were insufflated into the middle ear cavity of 7 guinea pigs. Pure oxygen, insufflated into the middle ear cavity, easily permeated the round window membrane and elevated the perilymphatic oxygen tension. Oxygen transport to the inner ear, other than by the inner ear vessels, was confirmed. The inner ear function may partially be maintained by oxygenation through this route.