We have already shown that photodynamic therapy using of a new photosensitizer, pheophorbide-a (Ph-a) would be useful for cancer treatment.
In this report, we have studied the sensitivity to Ph-a in 5 cancer cell lines which were derived from the oral region.
It has been revealed that oral squamous cell carcinoma (SCC) cells were shown to be more sensitive to Ph-a in comparison to salivary gland-derived adenocarcinoma (SAC) cells. The SCC cells which were sensitive to Ph-a demonstrated an increased intra-cellular level of Ph-a in comparison to SAC cells. These results indicate that the accumulation of Ph-a in the cells should reflect to the cytotoxity. In addition to these findings, it was revealed that SCC cells exhibited an increased level of reduced glutathione (GSH), glutathione peroxidase (GSH-Px) activities, and glutathione S-transferase (GST) activities in comparison to SAC cells.

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As it is impossible to perform a longitudinal experiment of carcinogenesis of human samples, experimentally induced carcinoma has been used for this purpose. DMBA induced carcinoma on hamster buccal pouch mucosa has been frequently cited for its stability and high induction rate. We have been attending to this aspect of research. This article presents the findings from PAS stained sections on the process of DMBA induced hamster buccal pouch carcinogenesis.
The PAS-positive granules in the cytoplasm of epithelial cells, regarded as glycogen, were consumed by digestion of amylase. There was no difference between the experimental groups painted DMBA for no more than 6 weeks and the control groups which contained very little glycogen. But on the groups painted for more than 8 weeks, papillomas accumulated a large amount of glycogen in the cytoplasm of the spinous cell layer, and carcinomas did a little in the keratinized part. Epithelium with atypia revealed less glycogen than that of the other part of the epithelium. Carcinoma in situ contained extremely less.
Concerning on the PAS-basement membrane, that is PAS positive membraneous structure at the epithelium-connective tissue junction, there was no distinct difference between the controls and the up to 6-week-painted groups. In the groups painted more than 8 weeks, papillomas occasionally had thin membranes, and carcinomas were absent or faint.
Glycocalyx in the intercellular spaces was clearly observed in the controls and the up to 6-week-painted groups. Papillomas reduced the intercellular cohesion, and carcinomas showed wide intercellular spaces without any glycocalyx. The epithelium with atypia and carcinoma in situ also reduced intercellular cohesion.
Although PAS staining on the DMBA induced carcinogenesis could not predict the malignant potentiality of the epithelium, it is clarified that the induced tumors and epithelia with atypia closely resembled human oral carcinomas and precancerous lesions.

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Generally, a mouth wound heals faster than one in any other region of the body. Biological factors in saliva, such as kallikrein, amilase, lysozyme, immuno-globulin, renin, nerve growth factor and epidermal growth factor may influence wound healing-that is epithelialization, contraction, collagen synthesis, and scar remodelling. In this paper, we report the effect of saliva to the standard sacral open wounds of mice, varied with the caging method as follows:
group 1: wounded mouse caged in isolation.
group 2: two wounded mice caged together.
group 3: wounded mouse caged with mouse priorly sialectomized (Sublingual and submandibular gland). The wound area was measured every 7 days after surgery.
We obtained the results as follows:
1. We realized significant differences in each group. These findings suggest that biological factors in saliva accelerate wound healing.
2. Difference in the wound healing process between groups 2 and 3 suggests that the amount and characterization of saliva effect on the wound contraction.

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The healing process of the injured condylar cartilage of the temporomandibular joint (TMJ) was investigated in rats to as certain the fine structural characteristics of the repaired tissue and the influence of age on healing.
Cartilage injury was prepared by cutting the condylar heads of Wistar male rats (4 weeks, 16 weeks, and 1 year old) to the subchondral bone with a # 700 dental fissure bur.
The animals were sacrificed immediately and 3 days, after the operation and 1, 2, 3, 4, 6, and 10 weeks postoperatively and were examined both histologically and ultrastructurally.
The results obtained were as follows:
1. In the young group (4 weeks old), proliferation of cartilage cells occurred in 2-3 weeks and cartilaginous repair was completed 6 weeks after operation.
2. In the young adult group (16 weeks old), the proliferation of undifferentiated mesenchymal cells from the surface proliferating cell zone to the deep layer was observed.
The above-mentioned cells differentiated to chondrocytes 4 weeks postoperatively.
The differentiation of undifferentiated mesenchymal cells in the bone marrow into chondrocytes was also suggested, and cartilaginous repair was completed by 10 weeks after operation.
3. In the old group (1 year old), the proliferation of undifferentiated mesenchymal cells was not obvious until 2-3 weeks after operation. Although the cells differentiated into chondrocytes in 4-6 weeks, collagen fibril formation was insufficient in the lower level of the repaired tissue.
4. In all of the groups, the main findings regarding healing was undifferentiated mesenchymalcells in the surface layer of TMJ condylar cartilage (initially in the proliferating cell zone).
It was shown that these cells have remarkable potential for healing in condylar cartilaginous tissue.

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As a result of the development of reconstructive surgery in the head and neck using various flaps, radical operation for a malignant disease has facilitated, and therapeutic results have remarkably improved.
Forty-one patients who underwent reconstruction of the composite mandibular defect in our clinic for the past nine years were reviewed, and the results were as follows.
1. Thirty patients were reconstructed using a pectoralis major myocutaneous (PMMC) flap combined with an A-O reconstruction plate (19 cases), an almina ceramic implant (2 cases), or without mandibular reconstruction (9 cases), one using a rib-latissimus dorsi osteomyocutaneous flap, and ten using a free vascularized composite graft.
2. In reconstruction with a PMMC flap, flap survival rate was 90% and satisfactory results were obtained as to reconstruction of the soft tissue.
Disadvantages of a PMMC flap are mainly bulk and limitation of the flap rotation. As to mandibular reconstruction, on the other hand, about one third of the cases had complications such as loosening of fixative devices, exposure or breakage of the implant.
3. In reconstruction with a free vascularized composite flap, a radial forearm flap with hemi-radius was indicated in a marginal mandibulectomy, and a vascularized fibular graft with skin in a segmental mandibulectomy.
4. Free vascularized composite grafts gave better results than PMMC flaps, especially in mandibular reconstruction because of less resorption and infection. However, indications of free flaps should be carefully considered, especially in patients who have systemic diseases and those who are older than 65 years old because the result is all or none.

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We estimated the cosmetic appearance of the face, clearness of articulation and chewing function in 30 patients with squamous cell carcinoma of the lower gum or oral floor who had received marginal, segmental resection or hemisection of the mandible. We also investigated the number of the patients who were using the denture after the operation. The post-operative cosmetic appearance and oral functions were estimated by both the patients themselves and the dentists in this study.
The cosmetic appearance of the face and the chewing function were better in the patients who had received the marginal resection than in the segmental resection or hemisection in contrast to no obvious difference in the clearness of articulation regardless of the type of the resections. This result indicates that the continuity of the mandible is important to keep or restore the cosmetic appearance and the chewing function.
On the other hand, only 13 out of the 30 patients were using the post-operative denture. It would be necessary to let the patients make use of the post-operative denture with better retention and stability in order to keep or restore the post-operative oral function.

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Mandibular movements in 22 patients with mandibular prognathism were measured using a three-dimensional movement analyzing system developed at Kyushu University and compared with those of 20 controls, and also investigated differences between deviation prognathism and non-deviation prognathism.
1. Comparison of the values of mandibular movements between patients with mandibular prognathism and controls.
1) Analysis of mandibular movements revealed that interincisal distance (Im) for the patients was larger than that for controls, but there was no difference between the groups in maximum distance of the condylar path.
2) The distance of incisal path (I) and antero-posterior distance of condylar path (Cs) during protrusive and lateral movements was smaller in patients than in controls, but this difference was not significant. The curve length of condylar path (C) was significantly smaller in patients than in controls.
3) There was significant correlation between C and Cs (correlation coefficient r=0.849-0.975), suggesting that C could be estimated if Cs were known.
4) The ratio of the distance of condylar path of protrusive (Cps) or lateral movement (Cls) to the maximum distance of condylar path (Cms) was calculated, and found to be smaller in patients than in controls.
5) There was significant correlation between the values of movements of the incisal point and condylar points, suggesting that C and Cs could be estimated if “I” were known.
2. Comparison between non-deviation prognathism and deviation prognathism of the mandible.
1) Non-deviation prognathism of the mandible showed no significant difference between the deviated and non-deviated side on any parameter.
2) Deviation prognathism of the mandible showed no significant difference between the sides for maximum distance of condylar path.
During protrusive movement, the incisal point translated for the median line of the upper jaw, and the length of condylar path of the deviated side was significantly larger than that on the non-deviated side.
During lateral movement, condylar path (the deviated side) and incisal path length were significantly larger when the mandible moved toward the non-deviated side.
The results described above suggest that during protrusive and lateral movements, the length of the incisal path and the condylar path of the mandibular prognathism are somewhat smaller in the patients than those in controls, and that deviation prognathism of the mandible presents functional as well as morphological asymmetry.

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