Stress response to surgical procedures in the submandibular region and its influence on salivary secretion in mice

Saliva stimulated by pilocarpine was collected from the mouths of adult ICR male mice after either submandibular-sublingual gland (SM-SL) exposure and SM-SL removal under pentobarbital anaesthesia. Salivary flow rates decreased and salivary protein concentrations increased after both surgical procedures. Serum cortisol was elevated after the operations. Salivary protein separation patterns on sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) from surgically treated animals were very similar to those from mice given an alpha 1-adrenergic agonist (phenylephrine), but differed significantly from those given a beta-adrenergic agonist (isoproterenol). When the SM-SL was completely removed (i.e. parotid saliva), protein concentrations also dramatically increased. The SDS-PAGE protein separation pattern in the mice whose SM-SL had been removed was very similar to that in those whose SM-SL had been exposed. Hence, a surgical insult in the submandibular region in mice enhances the secretion of salivary protein, mainly in response to alpha 1-adrenergic receptor stimulation in the parotid gland. This study suggests the usefulness of alpha 1-adrenergic receptor-stimulated parotid salivary protein as a marker of surgical insult.     

Reconstruction of shallow upper buccal sulcus deformity secondary to cleft lip and palate repair

Shallow upper buccal sulcus deformity, one of the secondary deformities after cleft lip-palate repair, causes both aesthetic and functional problems. This deformity also prevents or makes difficult orthodontic and prosthodontic procedures. An upper buccal sulcus deepening procedure was performed in 14 patients during the last 5 years. In 12 cases, premaxillary-based mucosal flaps were combined with one of the following: lip re-repair, Abbé flap, or bilateral buccal mucosal advancement flaps; in two cases, premaxilla was grafted with buccal mucosal graft together with bilateral buccal mucosal advancement flaps. The follow-up period was 2 to 5 years. Results were satisfactory for the surgeon, orthodontist, prosthodontist, and the patient. Upper buccal sulcus reconstruction with premaxillary thin mucosal flap or full-thickness mucosal graft combined with tissue-sparing techniques provides successful and durable results.     

Experimental model of invasion and metastasis by orthotopic transplantation of oral squamous and adenoid cystic carcinomas into the tongue of nude mice

Three squamous cell carcinoma (SCC) cell lines established from oral cancer, seven specimens of SCC and three of adenoid cystic carcinomas taken from the oral cavity during operations were transplanted into the tongues of nude mice. Metastases to the regional lymph nodes and the lungs were examined histologically. We were able to transplant every cell line or specimen of tissue into the tongue of nude mice, and found that cancer transplanted in the tongue invaded diffusely to the surrounding tissues without forming a capsule, and that the mode of invasion of the transplanted SCC was similar to that of the biopsy specimen of the patient from whom the material had been obtained. We also found that all three of the SCC cell lines, 3 of the 7 SCC specimens and 2 of the 3 adenoid cystic carcinoma tissues metastasized to the regional lymph node. SCC did not metastasize to the lung, but in two of the three adenoid cystic carcinomas we did see micrometastases to the lung. The study indicates that this method can be used as a model of metastasis in oral squamous cell carcinoma and adenoid cystic carcinoma to show the stages of metastasis in cancer.     

Placement of implants in distraction osteogenesis: a pilot study in dogs

This study investigated the possibility of achieving osseointegration of implants placed in a distracted site during the consolidation period. Four healthy male mongrel dogs were used in this experiment. A subperiosteal corticotomy around the mandible was performed between the left mandibular premolar and first molar. After a 7-day latency period for soft tissue healing, the distraction was performed at the rate of 1 mm per day for 14 consecutive days to allow for 14 mm of elongation, using an extraoral distraction device. Three weeks after the completion of distraction, screw-type implants were placed in the distracted site. Twenty-four weeks after placement of the implants, they were stable, and osseointegration had been achieved physically, radiographically, and histologically. These results suggest the possibility of shortening the period of implant treatment by using the distraction osteogenesis technique.     

Radiation dose reduction during endodontic therapy: a new technique combining an apex locator (Root ZX) and a digital imaging system (RadioVisioGraphy)

This study was undertaken on 14 teeth in order to evaluate a new technique for radiation dose reduction during endodontic therapy. After examination of the preoperative film, usually available in the patient file, an apex locator (Root ZX) was used to measure the working length. Complete chemomechanical debridement was then performed, and the master cone was evaluated by a digital imaging system (RadioVisioGraphy (RVG)). Obturation was performed when measurements of the electronic device and RVG were comparable. A postoperative image was made by the RVG system to evaluate the final obturation. A clinical and radiographic follow-up examination (follow-up period: 6 to 8 months) revealed satisfactory apical healing. These results indicated that a successful obturation technique can be performed by a single radiation exposure, using the RVG unit for master cone evaluation. This technique may be useful in medically compromised patients who need not to be exposed to excessive or repeated radiation during endodontic therapy.     

Temporalis muscle flap for craniofacial reconstruction after tumor resection

Temporalis muscle flap provides a good solution for the reconstruction of craniofacial defects after tumor resection. Nine patients with complicated defects located at the upper two thirds of the face, anterior cranial base, or mastoid region are presented. Five patients had orbital exenteration, two with total maxillectomy and two with anterior craniofacial resection. Temporalis muscle flap provided profuse well-vascularized tissue for the obliteration of orbital exenteration and total maxillectomy cavities and coverage of surface defects. Cranial, oral, and nasal spaces were separated successfully in all patients. Temporalis muscle flap is a very reliable technique with low complication rates and few donor site problems. This safe and technically easy flap can be preferred for the reconstruction of craniofacial defects after ablative tumor surgery, especially in older and debilitated patients.     

Expression and activity of thrombomodulin in human gingival epithelium: in vivo and in vitro studies

Epidermal keratinocytes thrombomodulin (TM) has been shown to regulate thrombin at sites of cutaneous injury in addition to a role for epidermal differentiation. TM, a major anticoagulant proteoglycan of the endothelial cell membrane, is a thrombin receptor that acts as a co‐factor for protein C activation. Thrombin has pro‐inflammatory effects for periodontitis. However, little is known about TM in gingival tissue with periodontitis. We used immunohistochemistry to examine expression of TM in gingival epithelium from patients with periodontitis. In vitro , we observed TM expression at varying Ca²⁺ concentrations by confocal laser scanning microscopy, examined the expression of TM mRNA and tested TM co‐factor activity. Furthermore, we measured TM concentration in gingival crevicular fluid (GCF) from 11 severe adult cases of periodontitis using enzyme‐linked immunosorbent assay. Immunoreactive TM was present in gingival epithelium and junctional epithelium, and was reduced in inflamed gingival epithelium compared to healthy gingival epithelium. Ultrastructurally, TM, including microvilli, was observed on the cell membrane. TM localization in cells cultured in 0.09 m m Ca²⁺ differed from that in cells exposed to 1.2 m m Ca²⁺. Northern analysis demonstrated TM mRNA in gingival keratinocytes more than in human umbilical vein endothelial cells (HUVEC). Gingival keratinocytes also facilitated protein C activation by thrombin, although less strongly than HUVEC. TM in GCF at sites with bleeding on probing in patients was significantly elevated ( p <0.001, Student's t ‐test). TM in gingival epithelium may regulate thrombin activity at sites of coagulation and inflammation with periodontal disease, although inflammation may impair this regulation of thrombin.     

Maxillary sinus augmentation prior to placement of endosseous implants: A histomorphometric analysis.

The aim of this prospective study was to histomorphometrically evaluate at various time intervals the mineralization stage and process of an allogeneic-xenogeneic bone graft used in sinus augmentation procedures. One biopsy was taken from 20 patients at either 6, 8, 10, or 12 months after sinus augmentation. Immediately following the biopsy, an endosseous implant was placed into the biopsy site. This protocol provided 4 groups of 5 patients each, based on healing time following sinus augmentation. Using backscattered electron image analysis, the specimens were histomorphometrically analyzed to determine the volume fractions of residual cancellous bone, newly formed bone, soft tissue, bovine hydroxyapatite, and "remineralized" freeze-dried demineralized bone allograft (rDFDBA). "Remineralization" of DFDBA particles was observed in a few areas in all specimens. Polarized light microscopy showed that only the 12-month biopsies had a predominance of lamellar bone formation. The area within the biopsies that represented the residual alveolar ridge consisted of 32.6% +/- 8.6% (mean +/- SD) of bone. In the grafted area of the biopsies the volume fraction of newly formed bone at 12 months (20.7% +/- 8.3%) was significantly higher (P < .05, analysis of variance) than at 6 months (8.1% +/- 3.0%). There was no statistically significant difference between newly formed bone in the inferior, central, and superior grafted areas in all 4 time intervals. This prospective study indicates that the mineralization process of an allogeneic-xenogeneic sinus graft is incomplete 6 months after the sinus augmentation procedure. New bone formation increased up to 12 months postaugmentation; however, it remained lower than the volume of residual bone.     

The reproducibility of cephalometric landmarks: an experimental study on skulls

Few previous cephalometric studies have used dry skulls in order to eliminate the effects of the facial soft tissues. The aim of this study were to quantify the intra-examiner reproducibility of the commonly used cephalometric landmarks, angles and distances, using dry skulls and to compare these errors with previous error data obtained from normal cephalograms of living patients. Thirty skulls were mounted in a purpose-designed holder and repeat cephalograms of each skull were recorded and digitised. All measurements were made relative to an X-Y coordinate reference grid. Scattergrams were produced to show the characteristic distribution of the intra-examiner reproducibility errors for the landmarks, and the reproducibility of the angles and distances were tabulated. This data was compared with a related study that included the soft tissue profile. The standard deviations of the skeletal and dental angles and distances were greater in the presence of the soft tissues. These differences were up to four times larger for measurements including the location of Nasion (e.g. SNA, SNB and SNPg), which was the landmark location most affected by the presence of soft tissues, and for the distance: Incisal tip of Lower Incisor to Pogonion. Anterior Nasal Spine, in the horizontal plane, was also greatly affected by the presence of the soft tissues. By using dry skulls, the errors observed in this study may serve as standards for the rational interpretation of clinical cephalometric values.