Splint Therapy for Periodontal Treatment
Horizontal position is secured in clasp dentures by the rigid parts of cast clasps, such as clasp bodies, shoulders, and upper arms. They secure the denture against horizontal displacement and twisting and, in interaction with the rigid denture frames, evenly transfer masticatory pressure to other segments of the dental arch. They produce a splinting effect for the abutment teeth.
This splinting effect by clasp retention of periodontally compromised teeth can be exploited for therapeutic purposes when a dentition with spaces or wide sections of teeth is completely clasped together. Therefore, fixed or removable splints are fabricated to treat periodontally damaged dentitions with reduced loading capacity of individual teeth or groups of teeth or to stabilize dentitions with gaps.
Removable splints in the model-casting method as a continuous ring of clasps or in a cap shape are guided around the teeth and can be linked to a rigid unit by a large connector. They reduce horizontal and vertical movements of the splinted teeth without entirely preventing these movements.
Fixed splints comprise a soldered group of partial crowns that are anchored in the tooth by parallel grooves and parapulpal pins. Inlay splints are made up of mesio-occlusodistal inlays that are soldered together or joined with pin attachments. Fixed splinting components are periodontally hygienic and often esthetically more acceptable. However, they tend to provide local or complete blocking effects as they prevent both horizontal shifts and vertical movements of the clasped teeth. This gives rise to a block of resistance to all sagittally and transversally acting forces.
Partial dentures, which are used with rigid anchorage and support components, offer such blocks of resistance. A primary blocking situation can be produced by bar connectors and a secondary blocking situation by telescope crowns and anchorage with attachments.
If a splint is part of a denture in the form of continuous reinforcement, the teeth and the denture form a functional unit that stabilizes the residual teeth, distributes masticatory pressure, and secures the horizontal position of the denture. Full reinforcement with alternating interdental insertion prostheses also delivers the desired splinting effects.
Splints can be fabricated without being integrated into a denture. The following paragraphs describe the different designs available.
The Elbrecht splint is a continuous bar produced by the model-casting method that is guided in a ring shape over the equator of each tooth (Fig 11-33); the splinting is stiffened by a large rigid connector (sublingual bar, reduced plate). The horizontal movements of the teeth are meant to be limited by this splinting so that the teeth are secured in their tooth bed. Because the splint also passes over the vestibular surfaces of the anterior teeth, it is esthetically disadvantageous and therefore is often modified into a crib splint.
In a crib splint, the continuous bar only runs on the lingual surfaces and engages in prepared niches on the incisal edges (Fig 11-34). The enclosure and hence the splinting effect are limited in the process.The prepared incisal edges are at risk of caries.
The cap splint encloses the teeth incisally or on the masticatory surface with cast, accurately fitting caps (Fig 11-35). An excellent splinting effect is produced due to the good bodily grasp on the teeth. A cap splint is indicated if a sublingual bar cannot be placed because the floor of the mouth is high. Its disadvantages are the esthetic impression and the extensive coverage of the tooth surface, under which caries will develop if oral hygiene is poor.
The lingual splint covers the lingual surfaces of the teeth and has interdental cribs (Fig 11-36). It is indicated if the floor of the mouth is high, and it is esthetically better than a cap splint while producing the same splinting effects. Its disadvantages are again the extensive coverage with the risk of caries.
The Weissenfluh splint is a lingual splint that is suspended in the tooth with parallel pins. In addition, sleeves are cemented into parallel parapulp-al drill holes in the lingual surfaces. The splinting effects and the esthetics are very good with this splint, but it is difficult to fabricate. Furthermore, there is also a risk of caries under the extensive coverage.