[Unusual location of an oral squamous cell carcinoma]. / Ongewone lokalisatie van een mondholtecarcinoom.

A 52-year-old woman was found to have a small squamous cell carcinoma of the palatal gingiva of teeth 21 and 22. Such a location is extremely rare. Treatment consisted of a partial maxillectomy. The defect was closed by a partial denture. During the 5 year follow-up period no signs of local recurrence or metastatic spread occurred.

Squamous cell carcinoma of maxillary sinus.

BACKGROUND: Medical records of 43 patients with histologically proved diagnosis of squamous cell carcinoma who were treated between the years 1975 and 1994 at the department of Otolaryngology Head Neck Surgery, VU Amsterdam were examined. METHODS: Tumors were restaged according to UICC classification 1997. Thirty-eight patients were treated for cure, nine were treated with chemotherapy followed by external beam radiotherapy, and 28 patients were treated with surgery followed by postoperative radiotherapy. No patient was lost to follow-up. Data with respect to survival were analyzed. RESULTS: Eighty-three percent of the tumours were in stage III or stage IV at the time of first presentation. Five-year survival after surgery and postoperative radiotherapy for all patients was 64%. For stages II, III, and IV it was 83%, 49%, and 37%, respectively. Cervical nodal metastases were present in 4.1% at the time of presentation. Thirty-seven percent of the patients survived 2 years after chemotherapy followed by radiotherapy. CONCLUSIONS: Squamous cell carcinoma continues to be diagnosed late. Surgery followed by radiotherapy remains the treatment of choice. Mandibulotomy should be considered for better clearance of retromaxillary space in T3 -T4 tumors. The eye should be preserved whenever it is oncologically safe to do so.

Development of transplanted pulp tissue containing epithelial sheath into a tooth-like structure.

The aim of these studies was to find out whether intact neonatal pulp tissue containing residual epithelial cells can induce the development of a tooth-like structure in situ. First maxillary neonatal hamster molar pulps containing adhering undifferentiated epithelial cells were transplanted submucosally in the oral cavity of recipient mothers for periods ranging from 2-8 weeks and the tissues were then processed for light microscopy. Developing tooth-like structures containing mineralised tubular dentine, predentine and a vascularised pulp-like chamber lined with functional odontoblast-like cells were observed in the specimens within 2 weeks of transplantation. Enamel and root formation were not observed. These data indicate that neonatal dental pulp tissues containing epithelial cell remnants have the capacity to develop into tooth-like structures and that this could be the explanation for the development of tooth-like structures sometimes observed in infants after extraction of a natal tooth.

The effects of NaF, alpha-C12DMEAHF and alpha-C12DMEAHCl on caries development in dentine in situ.

Using histological techniques it was possible to demonstrate that during in situ caries development in bovine dentine, the demineralization process preceded the emergence and changes in the organic matrices. In addition, these data demonstrated as that 0.006% F- given either as the quaternary ammonium compound or NaF completely prevented demineralization by acting primarily on the dentine mineral. Inhibition by the quaternary ammonium compound alone was incomplete probably through repression of acid production by micro-organisms normally resident in the saliva.

[Tongue prosthesis]. / De tongprothese.

Surgical treatment for tumors of the tongue and floor of the oral cavity often results in impaired swallowing and speech function. A method is described to improve oral functions after total glossectomy by constructing a removable tongue prosthesis in a multidisciplinary clinical practice.

The effects of quaternary ammonium chloride (alpha C12 DME AHCl) on enamel hardness and mineral loss under intra oral cariogenicity test conditions.

The effects of a quaternary ammonium compound; 2-hydroxy-ethyl-2-hydroxydodecyl-dimethyl-ammonium chloride (alpha C12 DMEAHCl) on enamel hardness and mineral loss in enamel slabs were studied under intra-oral cariogenicity test conditions. The quaternary ammonium compound without fluoride reduced enamel softening as well as the mineral loss from enamel significantly up to a depth of 100 microns from the surface. Moreover the Ca/P molar ratio of the treated enamel was comparable to untreated enamel controls. These findings suggest that the quaternary ammonium compound itself inhibits mainly demineralisation rather than remineralization under intra-oral cariogenicity test conditions.

Hardness changes and mineral loss in enamel during the intra oral cariogenicity test in the presence of 0.125% EHDP with or without 0.1% F-.

The effects of a high EHDP concentration (0.125%) were measured under Intra Oral Cariogenicity Test (ICT) conditions in the presence or absence of F- (0.1%). EHDP as well as EHDP supplemented with F- inhibited the softening of enamel slabs to a similar extent as measured by microhardness. Measurements of the calcium and phosphate levels as a function of depth showed that the addition of F- to the EHDP solution further decreased mineral loss in the deeper layers. The results suggest that the inhibition of demineralization of the enamel by EHDP and F- is due to inhibition of acid production by microorganisms.

Comparison of the hardness change and mineral loss in enamel by dimethyl ammonium fluoride (alpha C12 DMEAHF) or NaF treatment under intra oral cariogenicity test conditions.

Changes in hardness as well as in Ca and P were determined in enamel slabs after treatment with 3% sucrose together with NaF or alpha C12 DMEAHF (both containing 0.006% F-) under Intra Oral Cariogenicity Test conditions. NaF treatment resulted in a hypermineralization of the surface of the enamel lesion suggesting formation of CaF2. Treatment with ammonium fluoride along with the same low F- concentration inhibits the caries process completely and seems to be a very promising anticaries agent.

Comparison of the effects of 0.1% F- and 0.025% F- on mineral loss in enamel under intra oral cariogenicity test conditions.

Although the caries reducing effect of fluoride (F-) is very well known, the optimal fluoride concentration is still unknown. Therefore we compared the effects of a high (0.1% F-) with a low (0.025% F-) concentration under Intra Oral Cariogenicity Test (ICT) conditions using microhardness measurement and microdissection techniques with which it is possible to quantify the amount of Ca and P present in consecutive enamel layers. No significant differences could be demonstrated between high and low fluoride concentrations in the mineral loss in the surface layer as well as in penetration depth measured perpendicularly to the surface. The reduction of mineral loss after ICT was more pronounced with high fluoride concentrations especially in layers deeper than 150 microns. Using 0.025% F- this effect was restricted more towards the surface. Concomitantly with both F- concentrations a higher Ca/P ratio was observed compared to the sucrose treated or untreated controls.

The effect of daily application of a neutral 0.25% F- mouth-rinse on mineral loss in surface layers of enamel under intra oral cariogenicity tests conditions.

The effects of daily use of a 0.025% F- mouth-rinse on microhardness and mineral loss in the enamel lesion has been studied under Intra Oral Cariogenicity Test (ICT) conditions. The penetration depth was changed from 16 to 9 microns by F-. Moreover, the inhibition was found fairly constantly distributed over the whole lesion for the Ca and P loss without any CaF2 formation. In this way the effectiveness of the 0.025% F- mouth-rinse program can be explained.