Radiation protection rail
In dentistry, a radiation protection splint is understood to be a mucous membrane retractor ( lat. Retrahere, “to withdraw”), which causes a dose reduction on the oral mucous membranes in the event of tumor radiation in the head and neck area. The correct name is soft tissue retractor , because on the one hand not only mucous membranes are affected and on the other hand the term radiation protection splint gives the incorrect impression that a protective device is used for the high-energy radiation during radiation therapy . As a rule, you need a soft tissue retractor for the upper and lower jaw.
function
Metallic restorations in the mouth, such as crowns and bridges , generate scattered rays when they hit ionized radiation , which lead to a considerable increase in dose on the directly adjacent mucous membranes . The effect of the irradiation is based on the transfer of energy to the irradiated tissue in scattering processes . Direct hits on biomolecules that are essential for cell growth are less important than the ionization of water molecules. The resulting free radicals are highly toxic and chemically react with cell components. The resulting damage, especially DNA double-strand breaks, are responsible for the destructive effect. With a gold crown, for example, the scattered radiation is 80 Gy (Gray). The soft tissue retractor creates a distance between the metal and the mucous membrane, which leads to a considerable reduction in the dose of radiation on the mucous membranes. In a way, it is a spacer. A distance of between three and five millimeters is sufficient, which also corresponds to the layer thickness of the retractor. According to the law of the square of the distance , due to the divergence of ionizing radiation, the dose per area decreases with increasing distance from the focus. The intensity of the radiation decreases with the square of the distance. If, for example, a distance between a gold crown and the mucous membrane is increased from 0.5 mm to 3 mm by the retractor, i.e. six-fold, the radiation intensity of the scattered radiation is only about 3% compared to radiation without a retractor, i.e. only 2.2 Gy. The splint reduces the reactions on the oral mucosa that occur in the second and third third of a radiation therapy series and are irreversible. The resulting mucositis is the most significant undesirable, acute radiation side effect. The extremely painful mucositis represents the greatest impairment of the patient's quality of life and often limits oncological treatment, which reduces the chances of tumor healing.
Since these are devices that are intended to reduce the effects of scattered radiation through metal restorations, a soft tissue retractor is only necessary in the jaw in which there are metal restorations. If there are no metal restorations in the mouth, no soft tissue retractor is necessary. The soft tissue retractor is only worn during treatment.
Two further deep-drawn splints are produced as medication carriers in order to carry out fluoridation for the prophylaxis of radiation caries after radiation. A soft tissue retractor is not suitable as a drug carrier. A soft tissue retractor rests closely on the teeth. In contrast, a medicament carrier must have corresponding cavities between the teeth and the splint into which the medicament can be introduced.
Manufacturing
The production of a radiation protection splint is similar to the production of a bite splint . An alginate impression is taken from the dentition to make it. This is filled with super hard stone. On the plaster model by means of thermoforming unit 3-5 mm thick hot, PMMA films "pulled" through the model by vacuum. This blank is then cut out and processed by the dental technician . Radiation protection rails consist of an inner soft layer and an outer hard layer. The inner layer is soft so that the splint gives a little when it is pushed over the tooth equator (the most prominent part of the teeth) during insertion.
Billing
In Germany, the radiation protection rail is not a contractual service of the statutory health insurance companies. In individual cases, however, health insurance companies will cover the costs upon application by the dentist. In these cases, statutory insured patients are billed for each splint via item K2 (bite aid without adjusted surface) of the assessment standard for dental services (BEMA), which is rated at 45 points (approx. € 43), plus material and laboratory costs. In all other cases, the splint is billed privately and directly with the patient in accordance with Section 6, Paragraph 1 of the Fee Regulations for Dentists ("analog service"), since such splints are not listed in the GOZ either. A similar calculation is conceivable according to fee number 700 of the fee schedule for dentists (inclusion of a bite aid without adjusted surface), which is valued at 270 points (34.93 €, assuming 2.3 times the rate), plus material and laboratory costs.
Web links
- As a cancer patient to the dentist Publisher: Cancer Information Service of the German Cancer Research Center (DKFZ), German Dental Association (BZÄK), National Association of Statutory Health Insurance Dentists (KZBV), September 3, 2014. Accessed September 3, 2014
Individual evidence
- ↑ W. Dörr, J. Haagen, Treatment of Oral Mucositis in Oncology ( Memento of the original dated November 23, 2015 in the web archive archive.today ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Hans Hoffmann: Original examination questions with commentary GK 2. Radiology . Georg Thieme Verlag, 2002, ISBN 978-3-13-112574-3 , p. 225.
- ^ Andrej M. Kielbassa: Radiation therapy in the head and neck area: implications for dentists, ENT doctors and radiotherapists . Schlütersche, 2004, ISBN 978-3-87706-870-0 , pp. 120–.
- ↑ W. Dörr, E. Dörr u. a .: Side effects of radiotherapy in the oral cavity. In: MMW Advances in Medicine. Volume 152, Number 46, November 2010, ISSN 1438-3276 , pp. 37-39, PMID 21229722 .
