Three-dimensional finite element model to predict patterns of pterygomaxillary dysjunction during Le Fort I osteotomy.

The aim of this study was to determine whether non-linear three-dimensional finite element analysis (3D-FEA) can be applied to simulate pterygomaxillary dysjunction during Le Fort I osteotomy (LFI) not involving a curved osteotome (LFI-non-COSep), and to predict potential changes in the fracture pattern associated with extending the cutting line. Computed tomography (CT) image data (100 snapshots) after LFI were converted to 3D-CT images. 3D-FEA models were built using preoperative CT matrix data and used to simulate pterygomaxillary dysjunction. The pterygomaxillary dysjunction patterns predicted by the 3D-FEA models of pterygomaxillary dysjunction were classified into three categories and compared to the pterygomaxillary dysjunction patterns observed in the postoperative 3D-CT images. Extension of the cutting line was also simulated using the 3D-FEA models to predict the risk and position of pterygoid process fracture. The rate of agreement between the predicted pterygomaxillary dysjunction patterns and those observed in the postoperative 3D-CT images was 87.0% (κ coefficient 0.79). The predicted incidence of pterygoid process fracture was higher for cutting lines that extended to the pterygomaxillary junction than for conventional cutting lines (odds ratio 4.75; P<0.0001). 3D-FEA can be used to predict pterygomaxillary dysjunction patterns during LFI-non-COSep and provides useful information for selecting safer procedures during LFI-non-COSep.

Genetic epidemiology of tooth agenesis in Japan: a population- and family-based study.

Tooth agenesis is one of the most common congenital anomalies in humans. However, the etiology of tooth agenesis remains largely unclear, as well as evidence base useful for genetic counseling. Therefore, we estimated the prevalence and sibling recurrence risk, and investigated agenetic patterns systematically. Tooth agenesis was classified into two subtypes: hypodontia (one to five missing teeth) and oligodontia (six or more missing teeth). The prevalence of these two subtypes were 6.8% [95% confidence interval (CI): 6.1-7.7%] and 0.1% (95% CI: 0.04-0.3%), respectively, and sibling recurrence risk of these were 24.5% (95% CI: 13.8-38.3%) and 43.8% (95% CI: 26.4-62.3%), respectively. This result suggests that the severe phenotype, oligodontia, might be mostly transmitted in a dominant fashion. Using a simple statistical modeling approach, our data were found to be consistent with a bilateral symmetry model, meaning that there was equal probability of missing teeth from the right and left sides.

Prediction of neurosensory alterations after sagittal split ramus osteotomy.

Prediction of neurosensory deficit in the lower lip and chin after sagittal split ramus osteotomy (SSRO) is challenging. This study aimed to elucidate factors related to the development and improvement of neurosensory disturbance (NSD) after SSRO with respect to surgical procedure and the anatomical and structural characteristics of the craniomaxillofacial skeleton. Subjects comprised 50 patients treated by a single experienced surgeon. Anatomical data and landmarks were obtained by computed tomography (CT) imaging. There was a significant difference between patients with or without NSD for the surgical space on the medial side of mandibular ramus 1 week after SSRO (P=0.006). Less than 15.0mm between the lingula and mandibular notch (relative risk, 6.7; 95% CI, 1.7-33.8) and 195.0mm(2) or more space on the medial side of the mandibular ramus (relative risk, 17.2; 95% CI, 3.9-100.4) indicated a significant risk of NSD development at 6 months postoperatively. These results suggested that the development of NSD is related to the surgical space on the medial side of the mandibular ramus and subsequent manipulation of the inferior alveolar nerve (IAN) in that region. Limited periosteal degloving prevents excessive stretching of the IAN during SSRO, thus lowering NSD incidence.

Risk of surgical glove perforation in oral and maxillofacial surgery.

Oral and maxillofacial surgery, which involves several sharp instruments and fixation materials, is consistently at a high risk for cross-contamination due to perforated gloves, but it is unclear how often such perforations occur. This study aimed to address this issue. The frequency of the perforation of surgical gloves (n=1436) in 150 oral and maxillofacial surgeries including orthognathic surgery (n=45) was assessed by the hydroinsufflation technique. Orthognathic surgery had the highest perforation rate in at least 1 glove in 1 operation (91.1%), followed by cleft lip and palate surgery (55.0%), excision of oral soft tumour (54.5%) and dental implantation (50.0%). The perforation rate in scrub nurses was 63.4%, followed by 44.4% in surgeons and first assistants, and 16.3% in second assistants. The odds ratio for the perforation rate in orthognathic surgery versus other surgeries was 16.0 (95% confidence interval: 5.3-48.0). The protection rate offered by double gloving in orthognathic surgery was 95.2%. These results suggest that, regardless of the surgical duration and blood loss in all fields of surgery, orthognathic surgery must be categorized in the highest risk group for glove perforation, following gynaecological and open lung surgery, due to the involvement of sharp objects.

OmpA-like protein influences cell shape and adhesive activity of Tannerella forsythia.

Tannerella forsythia, a gram-negative fusiform rod, is implicated in several types of oral anaerobic infections. Most gram-negative bacteria have OmpA-like proteins that are homologous to the OmpA protein in Escherichia coli. We identified an OmpA-like protein in T. forsythia encoded by the tf1331 gene as one of the major proteins by mass spectrometric analysis. Two-dimensional, diagonal electrophoresis showed that the OmpA-like protein formed a dimeric or trimeric structure via intermolecular disulfide bonds. A biotin labeling experiment revealed that a portion of the protein was exposed on the cell surface, even though T. forsythia possesses an S-layer at the outermost cell surface. Using a tf1331-deletion mutant, we showed that the OmpA-like protein affected cell morphology. The length of the mutant cell was reduced almost by half. Cell swelling was observed in more than 40% of the mutant cells. Moreover, the mutant exhibited decreased adhesion to fibronectin, retarded autoaggregation, and reduced cell surface hydrophobicity. These results suggest that the OmpA-like protein in T. forsythia plays an important role in cellular integrity and adhesive function.

Imaging features contributing to the diagnosis of ameloblastomas and keratocystic odontogenic tumours: logistic regression analysis.

OBJECTIVE: The aim of this study was to clarify the characteristic imaging features that can be used to differentiate ameloblastomas from keratocystic odontogenic tumours and to examine the significant imaging features contributing to a correct diagnosis. METHODS: 60 observers (39 specialists in oral and maxillofacial radiology and 21 non-specialists) examined CT and/or panoramic images of 10 ameloblastomas and 10 keratocystic odontogenic tumours shown on a webpage and made diagnoses. Their correct answer ratios were then calculated. The imaging features of the tumours were evaluated and expressed as binary numbers or quantitative values. The imaging features that contributed to a correct diagnosis were elucidated using logistic regression analysis. RESULTS: The mean correct answer ratio was 61.3% ± 17.2% for the diagnosis of ameloblastomas and keratocystic odontogenic tumours. CT images produced higher correct answer ratios for diagnosis of keratocystic odontogenic tumours by specialists. The significantly different imaging features between ameloblastomas and keratocystic odontogenic tumours were the degree of bone expansion and the presence of high-density areas. The significant imaging features contributing to a correct imaging diagnosis were the number of locules, the presence of high-density areas and the inclusion of impacted teeth. CONCLUSION: The presence of high-density areas is the most useful feature in the differential diagnosis of ameloblastomas and keratocystic odontogenic tumours based on comparison of the imaging features of both tumours and examination of the diagnostic contributions of these features.

A novel mutation in the C-terminal region of RUNX2/CBFA1 distal to the DNA-binding runt domain in a Japanese patient with cleidocranial dysplasia.

Cleidocranial dysplasia (CCD) is an autosomal dominant inherited skeletal disease with high penetrance and variable expressivity. Although many mutations in RUNX2/CBFA1, an osteoblast-specific transcription factor, have been identified as causes of CCD, it is unclear whether these mutation genotypes relate to various symptoms. Heterogeneous mutations of RUNX2/CBFA1 result in disease characterized by abnormal skeletal genesis and dental disorders. There are few reports describing the relation between detailed orofacial pathology and the RUNX2/CBFA1 genotype. The case of a Japanese patient with severe orofacial dysplasia who was clinically thought to have CCD is described here. The authors performed mutation analysis on the RUNX2/CBFA1 gene and identified a novel frameshift mutation (722delT), which produces a mutant RUNX2/CBFA1 with a truncating C-terminus distal to the runt domain.

Analysis of VH gene rearrangement and somatic hypermutation in Sjogren's syndrome and IgG4-related sclerosing sialadenitis.

IgG4-related sclerosing sialadenitis is currently considered as an autoimmune disease distinct from Sjogren's syndrome (SS) and responds extremely well to steroid therapy. To further elucidate the characteristics of IgG4-related sclerosing sialadenitis, we analysed VH fragments of IgH genes and their somatic hypermutation in SS (n = 3) and IgG4-related sclerosing sialadenitis (n = 3), using sialolithiasis (n = 3) as a non-autoimmune control. DNA was extracted from the affected inflammatory lesions. After PCR amplification of rearranged IgH genes, at least 50 clones per case (more than 500 clones in total) were sequenced for VH fragments. Monoclonal IgH rearrangement was not detected in any cases examined. When compared with sialolithiasis, there was no VH family or VH fragment specific to SS or IgG4-related sclerosing sialadenitis. However, rates of unmutated VH fragments in SS (30%) and IgG4-related sclerosing sialadenitis (39%) were higher than that in sialolithiasis (14%) with statistical significance (P = 0.0005 and P < 0.0001, respectively). This finding suggests that some autoantibodies encoded by germline or less mutated VH genes may fail to be eliminated and could play a role in the development of SS and IgG4-related sclerosing sialadenitis.

Massive immature teratoma in a neonate.

Teratomas are embryonal tumours composed of diverse tissues from three germinal layers with variable levels of maturity. The authors report a female patient with a large immature epignathus. Prenatal diagnosis permitted a caesarean section and tracheotomy to be planned under ex utero intrapartum treatment for airway obstruction. The tumour was successfully controlled, even though it was impossible to distinguish from normal tissue because it lacked a pedicle and capsule, using multidisciplinary therapy, including a series of surgical treatments and adjuvant chemotherapy. This case suggested that the level of serum alpha fetoprotein might be a useful indicator after surgery. At present, after 4 years, no regrowth has been observed and the patient has no problems with respiration or swallowing.

A novel missense mutation in Van der Woude syndrome: usefulness of fingernail DNA for genetic analysis.

Van der Woude syndrome (VWS) is an autosomal-dominant oral facial disorder. To find a gene mutation in a Japanese family using fingernail DNA samples, we performed this study. We hypothesized that a gene mutation in IRF6 might be involved in VWS, and that fingernail DNA samples may be valuable for detecting such mutations. Linkage and haplotype analyses of the family mapped the disease locus to the 1q32-q41 region. Mutation analysis with an improved extraction method for fingernail DNA detected a novel missense mutation (1046A>T, E349V) in exon 7 of IRF6 in all the affected members of the family. Since the E349V change may disturb the hydrophobic core and affect regulatory activity of IRF6, it is most likely that the mutation is causative for VWS in this family. Fingernail DNA is thus useful for linkage and mutation analyses, since the fingernail can be easily obtained non-invasively, sent through the mail, and stored for a long period. We emphasize here the usefulness of fingernail DNA for the genetic analysis of a disease.

Patched homologue 1 mutations in four Japanese families with basal cell nevus syndrome.

AIM: To search for patched homologue 1 (PTCH1) mutations in four families with basal cell nevus syndrome (BCNS). METHODS: Mutation analysis of PTCH1 in unrelated Japanese families affected with BCNS was carried out by direct sequencing. RESULTS: Six novel PTCH1 mutations, 833G-->A in exon 6, 1415C-->A and 1451G-->T in exon 10, 2798delC in exon 17, 2918-2925dupAGTTCCCT in exon 18 and 3956C-->A in exon 23, were identified. CONCLUSIONS: Among the six PTCH1 mutations, two frameshift mutations (2798delC and 2918-2925dupAGTTCCCT) and one nonsense mutation (833G-->A) are predicted to lead to premature termination of PTCH1 protein translation. Three simultaneous mutations, 1415C-->A (A472D) and 1451G-->T (G484V) in exon 10, and 3956G-->A (R1319H) in exon 23, were found on one allele in only affected members in one family and none of them were found among 90 unrelated healthy Japanese. The three mutations on one chromosome may have resulted from errors in the recombinational repair process and this is the first report on the PTCH1 mutations due to such a mechanism.

A downward spread in acute parotitis.

Acute parotitis occasionally spreads rapidly down the neck with severe symptoms of swelling and pain. However, the inflammatory course of parotitis with extraglandular spread has seldom been described. On CT images, we have noticed a unique area just below the parotid gland that is surrounded by the platysma muscle and the superficial layer of the deep cervical fascia (DCF). In this case report, we describe the CT imaging features of acute parotitis, focusing on this area.

Cyclooxygenase-2 is a possible target of treatment approach in conjunction with photodynamic therapy for various disorders in skin and oral cavity.

BACKGROUND: Anti-cancer effects of cyclooxygenase (COX)-2 inhibitors have been reported, but not fully investigated in skin and oral diseases. 5-aminolaevulinic acid (ALA)-based photodynamic therapy (PDT) for treating those patients with skin and oral lesions is a highly sophisticated procedure, but the incidence of disease recurrence after treatment is rather significant. OBJECTIVE: To confirm that COX-2 could be a molecular target in adjunctive therapy to ALA-based PDT, we investigated (i) COX-2 expression in various skin and oral diseases, and (ii) the inhibitory effects on cellular growth of COX-2 selective inhibitor (nimesulide), ALA-based PDT and their combination on human oral squamous cell carcinoma (SCC) cell lines. METHODS: A total of 129 biopsy samples from the skin and oral mucosal lesions were tested immunohistochemically for COX-2 expression. Then the in vitro effects of nimesulide, ALA-based PDT, and their combination were determined on two SCC cell lines, HSC-2 and HSC-4. Three different methods (MTT assay, double-staining for annexin V and propidium iodide, caspase-3/CPP32 fluorometric protease assay) were applied for evaluation of their inhibitory effects on these two cell lines. RESULTS: Among the skin diseases, a considerable number of COX-2 high expressers were found in actinic keratosis (15 of 25, 60%), Bowen's disease (13 of 17, 76%) and extramammary Paget's disease (15 of 15, 100%). In contrast, only one of 33 (3%) basal cell carcinoma tumours was a COX-2 high expresser. Among the oral mucosal biopsies, the proportion of COX-2 high expressers increased gradually from hyperplasia (one of six, 17%) through mild dysplasia (five of eight, 63%) and moderate dysplasia (20 of 23, 87%) to severe dysplasia (two of two, 100%). Nimesulide had an inhibitory effect in vitro on HSC-2 (proven to be a COX-2 high expresser), but not on HSC-4 (a COX-2 non-expresser). While ALA-based PDT showed an inhibitory effect on both HSC-2 and HSC-4, most importantly the combination of nimesulide and ALA-based PDT demonstrated a significant synergistic effect on the cellular growth inhibition of only HSC-2, but not of HSC-4. CONCLUSIONS: Our study strongly suggests that COX-2 can be one of the molecular targets in treating various skin and oral diseases. The results from our in vitro experiments also prompt us to develop a new protocol with a combination of COX-2 selective inhibitor and ALA-based PDT for more effective treatment of those diseases.

[Is a maxillary prosthesis difficult for patients with trismus?].

Of patients with a postoperative maxillary defect, around 30% are though to have trismus to some extent. In these patients, some difficulty in fabricating a maxillary prosthesis is expected. In this study, 54 patients with trismus were compared with a control group to find some proof of difficulty in making a maxillary prosthetics. Fifty-four of trismus less than 20 mm of a mandibular stroke were experienced out of 185 patients with maxillary prosthetics between October 1984 and October 1992. The trismus was divided into 4 groups of less than 5 mm (1 case), 5 mm-10 mm (10 cases), 11 mm-15 mm (19 cases), and 16 mm-20 mm (24 cases). These case were analyzed by in taking an impression failure, average weight of the prosthesis, time needed to complete the prosthesis and some special form of prosthesis. No apparent differences among the 4 groups or with the control group were found. The cause of the difficulty in making a prosthesis for such patients with trismus are suggested not to be simply due to the range of mouth opening but also to the complexed space formed by the dental defect, alveolar bone defect, spreadability of the lip and the cheek, the mandibular stroke and the so-called scar bundle of the cheek next to the defect.

[The chronological changes in the size of maxillary defect].

Use of a maxillary prosthesis is now considered one of the good methods to ameliorate the crippling caused by the defect in the maxillary palate area after an ablative procedure for a maxillary tumor and it consumes no physical resources from the patient. There has been debate on whether the prosthesis should be made in the very early postoperative days or after the wound is stabilized. In this study, changes in the area of the defect in the palate after surgery were investigated by using plaster models from clinical cases we have experienced. Twenty-one cases were investigated according to the following features: "maxillary sinus cancer "+" more than 1.5 years of follow-up for maxillofacial prosthetics "+" presence of more than two casts of the case". These casts were photographed from a distance of 1.5 m, and the photographs were enlarged to the original size of the cast, then the defect area was measured with a Planimeter (Uchida Co. Ltd). The area of the defect had shrunk in 16 cases. It took over 1 year to get stabilized in 80% of the cases. It is believed to take around 3.5 years for all cases to become stable. This tendency had no relationship with the pattern of the defect, the stroke of the mouth opening, the pattern of the rest of the teeth, or the defect area itself. These findings suggest that it may be advisable to start the prosthetic work as early as possible rather than waiting for stability of the defect wound, to improve the patients's QOL.

[Maxillary prosthesis for better QOL--analysis of maxillary prosthesis stability].

We report here an analysis of 100 cases of maxillary prosthesis, experienced from July, 1981 through June, 1989, with special reference to stability. Sixty-four percent of prostheses were partial denture type and complete denture type comprised thirty-two percent. Eighty-six percent of cases were estimated to have defects exceeding 2/6 and 3/6 of the surface width of the palate. Ninety percent of prostheses weighed less than 15 gm. The stability of these prostheses was estimated to be good in 85% of cases, the stability of the denture type being good in 95% of partial denture type cases, and 62% of complete denture type cases. According to type distinctions among maxillary defects as a whole, in the smaller 1/6 and 2/6 defect cases, good stability can be expected, and in 3/6 and 4/6 defect cases, 80% achieve good stability. According to prosthesis weight, 80% of those weighing less than 15 gm were considered to have shown good stability. Thus, these maxillary prostheses can remain in place and functional ameliorating disability and contributing to the patient's quality of life.

[Maxillary prosthesis for better QOL--early setting and faster construction of maxillary prosthesis].

The maxillofacial prosthesis (MFP) is well accepted as one of the modalities to ameliolate the postsurgical crippling in the patients with maxillary malignancy. In this report, we analyzed 55 primary cases of MFP out of 100, from July, 1981 to July, 1987 in terms of the time of start after operation, and the duration and procedure of the MFP-making. MFP-making set about within 4 weeks in 35% of patients, 8 weeks in 25%, 12 weeks in 22%, and more than 12 weeks in 18%. The completion of MFP-making averaged 10 days. As a result of simplifying of MFP-making, we shortened a period requiring MFP-making within 3 days in recent 10 cases. There were no adverse effects of early wear of MFP after operation. We believe that early wear of MFP after operation improve the quality of life of patients with maxillary malignancy and considered that wear of MFP is not the completion of treatment, but is one of the procedures of treatment for the patients undergone maxillectomy.