BEGO professional Articles

In the case of tooth loss, the static structure of the dental arch changes. Forces that were originally harmoniously distributed to the complete dental arch are concentrated on the remaining teeth. Production of the denture must take into account the processes of saddle dynamics. This is the prerequisite for flawless masticatory function and protection of the oral structure against further damage. Indication of a partial denture frame exists in particular, if a reduced dental arch stands in the way integration of a purely periodontally supported denture (e.g. bridge) for static reasons. The partial denture closes the gaps.

In the mandible, under certain circumstances partial dentures should be given preference over bridge restorations. Failing that, long mandibular bridges should be divided up using ‘torsion attachments‘. Cemented bridges counteract the torsion in the mandible and restrict movement. In the worst case scenario they can break. This not only results in rapid loosening of the bridge, but also in breakage or chipping of the ceramic: patients suffer from headaches and jaw joint pain, the cause of which is often not determined.

The designation minor connector comes from American usage. Originally designated as clasp tail, it acts as a connecting element between the clasp and the base. It performs its primary task, transmission of forces and shear distribution, only if given an appropriate solid design. This frequently leads to a situation in which the patient feels the minor connector to be annoying. There is often insufficient space available for the dentures. Ideally minor connectors, such as that of a G clasp, run directly from the saddle to the clasp shoulder. The basal contact area is given a convex design for hygienic reasons. As a result, there is no broad contact of the minor connector to the natural tooth. An exception is the structurally desired function as a guide surface or embracement for insertion and removal of the denture. Normally the contact area of the minor connector to the clasp tooth corresponds to the approximal contact point between natural teeth.

In the premolar area, modified G clasp are predominantly used in connection with terminal clasp teeth. The mesial support represents an indirect saddle extension. The minor connector placed in a disto-oral position improves the support value of the G clasp. By shifting the minor connector in the disto-oral direction, the distance of the passive arm to the rest is shortened, thus enhancing the stability of the rest. At the same time the active arm becomes longer.

The anchoring of the denture or the force necessary to remove the denture (withdrawal force) is essentially defined through the undercut value and the clasp length. This undercut value results from the tooth status, the clinical, structural, as well as mechanical and geometric circumstances. The number and functional value of the retention areas used determine the withdrawal force. Ideally the clasp tooth should not be subjected to any horizontal shear when the denture is removed. A requirement for this is that the tooth is supported by a strong clasp element positioned opposite (reciprocator / embracement) at the same moment when the active clasp arm bends at the equator. The exact position of the embracement, which must be mounted at the same height, is determined with the analyzing rod. Often the requirement of an embracement cannot be structurally implemented. The horizontal shear on the clasp tooth should then be counteracted by means of a smaller undercut depth.

The planning and construction of partial dentures according to this methodology improves and facilitates the procedures and can be applied equally for analogue and digital work steps.

In this multi-part series, the author describes the ideal treatment approach using clasp-supported partial dentures. He advocates the opinion that the functional duration of such prostheses can be considerably extended if the frames are designed with a “system and concept”. A fault- and error-free partial denture frame rules out any complaints from the start and thus saves the laboratory unnecessary additional costs.

Source: Zubnoj Technik, April 2016, P. 42 - 46, BEGO
Language: Russian

Following metal casting and dental ceramics, 3D printing is the latest step in the manufacture of replacement teeth. Professor Dr Constantin von See and Dr Maximilian Meindorfer provide an overview of additive manufacturing technologies for the dental laboratory.

Source: Zubnoj Technik, April 2016, P. 69 - 72, BEGO
Language: Russian

Quale mercato avrà la protesi rimovibile nel prossimo futuro? Come si costruirà? Quali tecnologie utilizzeremo? Chi la costruirà Rispondendo a queste domande l’autore illustra la duplicazione, la prototipazione e il laser melting, tecniche e tecnologie con cui già oggi è possibile realizzare la protesi rimovibile.

Source: International Dental Products for China, August 2015, P. 6 – 8,MDT Siegfried Förster
Language: Chinese

Roland Strietzel examines the cost-effective production of high-quality restorations from BEGO.