Temporary and Permanent Splinting
by Dinh X. Bui, D.D.S., M.S.

Temporary and Permanent Splinting
The term splint indicates the act of fastening or confining, supporting, or bracing a displaced or movable part. In dentistry, splinting designates tying together or uniting two or more teeth in order to gain occlusal stability.There are numerous of splint design constructed with different splint material and aim at different purposes. In order to correctly and maximally delivering the therapeutic benefit of an occlusal splint, a clinician not only must understand the nature of the mechanism of splint therapy but also must be accurated in diagnosing the source of the problem. Several factors must be taken into account upon construction of the splint is to the determine whether the splint is temporary or permanent, extent of tooth coverage, the present state of occlusal harmonies in the patient and the oral habits of the patient. Splint may serve as palliative treatment, or relieving symptom appliance, or it serves as to permanently enhance the functional aspect of patient dentition. Success in splint therapy lies heavily on his or her ability to make an accurate diagnosis concerning the etiology of the patient’s functional disturbance.
Glossary of Periodontics term defines a splint as “any apparatus, appliance, or device employed to prevent motion or displacement of fractured or movable parts. A dental splint is an appliance designed to immobilize and stabilize loose teeth. Splint were classified as temporary, provisional, or permanent on the basis of duration and purpose. Temporary splints are those which are used less than 6 months during periodontal treatment and may or may not lead to other types of splinting. Provisional splints may be used from several months to years for diagnostic purposes, and usually lead to a more permanent types of stabilization. Permanent splint is a type of splint which is worn indefinitely and could be fixed or removable.
Morton Amsterdam and Lewis Fox in 1959 outlined the principles and technics of splinting. They defined that the term provisional splinting as the phase of restorative therapy utilizing a biomechanical combination of tooth dressing coverages and stabilization of teeth on an immediate and temporary basis. The rationales given for the procedures are to protect the investing structures of the teeth, to protect the pulp, to control of forces and stress, to establish physiologic occlusion, to be used as an evaluating procedure as revealed by functional requirement of the case, to serve as purpose of anchorage and stabilization of the cases requiring minor tooth movement, to treat periodontal cases which required both restorative and periodontal therapy to be executed simultaneously or required immobilization or to maintain periodontal result, and finally to establish the prognosis of a questionable teeth as it affects the final treatment plan. Requirement for the splints consists of color stability, esthetics, protective to pulp and occlusal forces, ease of fabrication and maintenance, safe, and capable of removal and insertion.
Simring in 1952 described the theory and practice of splinting in detail. He emphasized the importance of direction of forces and the movement of teeth under occlusal loads, thus rationalized the need for splinting as the safety procedure to employ when a tooth must withstand a forces beyond its individual physiologic limits. Since occlusal forces are multidirectional, he noted that an ideal splint would have to run not only mesiodistally but also buccolingually. In this case, splinting was carried around the arch. He also described the edentulous distance and the splinting effect. When three or more missing posterior teeth are replaced, the splinting effect must be increased by including at least three abutments when opposed by the natural dentition or a stationary bridge. Restoration replacing three or more missing posterior teeth and employing only two abutments may be considered when the opposing denture is a tissue borned removable appliance due to the resulting low occlusal force. Simring stressed that splinting is indicated where the traumatic effects of occlusion are intense and the stimulating physiologic action of the occlusal forces needs to be improved. Wherever splinting is indicated, thorough occlusal equilibration and adjustment must be indicated first. Finally, the most effective splinting is attainable only with cast crown soldered together.
Jens Waerhaug evaluate the justification for the splinting in periodontal therapy as a protective mechanism in the case of occlusal trauma. Clinical trials have shown the splints can do no harm. However, they may indicate that splinting may speed up destruction of bone rather than retard it. Fixed splints caused interference with oral hygiene. He outlined the adverse consequence for splinting as they represents unnecessary expense for patients, both fixed and removable splints may cause damage if not properly made, they are substituted for real periodontal treatment which is necessary to save teeth, and destruction of periodontium continues undisturbed by the splints.
Lemmerman in 1976 reviewed the rationale for splinting. He described the use of splinting as to device as to reduced the mobility or stabilized an existing mobility. He described the concept of reversible mobility, a type of mobility in the normal periodontium and will be able to reverse to normal following therapy. He compared this type to irreversible mobility, which were the type observed in a reduced periodontium and can only be reduced but never be completely eradicated. He suggest the possible rationales for splinting are a)to prevent mobility or drifting, b)the use in post acute trauma to enhance stabilization, c)prevention of drifting in normal dentition during occlusal therapy, or to d)provide functional comfort by preventing mobility in disease dentition. Thus Lemmerman are referred to the importance of the clinician to identify whether the drifting of teeth is a result of primary occlusal trauma (injury resulting from excessive occlusal forces applied to a tooth or teeth with normal support), and secondary occlusal trauma (Injury resulting from normal occlusal forces applied to a tooth or teeth with inadequate support).
In the case of primary occlusal trauma, the periodontium is intact and not reduced, thus the drifting of the teeth is due to an excessive, continuous force resulting from an occlusal disharmony. Elimination of this interference will provide permanent relief from drifting and sometimes completely reverse if diagnosed early. Splinting plays a very minor role, if any, in the case of primary occlusal trauma. Ferenez in 1991 reported that there is little rationale for splinting teeth manifesting primary occlusal trauma.
In the case of secondary occlusal trauma, the periodontium is reduced and the teeth lost a lot of support. The need for splinting thus is more obvious as to achieve stabilization. Splinting during or after periodontal treatment is often aimed to achieve reduction of mobility to improved comfort and function. Moreover, in the case which required periodontal surgery, splinting is used to eliminate movements in the healing area since micromovement of the surgical site may inhibit repair to take place in the healing area. Ferenez in 1991 also divided the splint into its duration of use: short term splint, provisional splints, and long term splint.
Occlusal forces applied to a splints are shared by all teeth within the splint even if the force is applied to only one section of the splint. The rigidity of the splint acts as lever, so that the forces applied to some teeth in the splint may be much greater than before splinting. This phenomena is utmost important in the case of unstable occlusion because the inclusion of a mobile tooth in a splint does not completely relieve the tooth of the burden of occlusal forces, nor does it guarantee against injury from excessive occlusal forces. One tooth within the splint with occlusal disharmonies may cause damage to periodontium of the other teeth in the splint, thus the occlusion needed to be stabilized prior to splinting. According to Caranza, two major indications for periodontal splinting are a)to immobilize excessively mobile teeth so that the patient can chew more comfortably and b)to stabilize teeth exhibiting increasing mobility. He further defined three procedures for provisional stabilization which are a) the reinforced resin splint for use in the posterior teeth, the acid etch resin splint for use in anterior teeth, and the resin bonded metal splint. As with any other appliance in the mouth, oral hygiene must be emphasized and must be taken into account in the design and construction of the splint.
Ramjford classified splint as temporary, diagnostic or provisional, or permanent. Temporary are used to reduce unfavorable occlusal forces for a limited time. This type of splinting can be seen in post acute trauma, in supportive measure in treatment of advanced periodontal disease, and for anchorage in orthodontic therapy. The diagnostic or provisional splint is used in borderline cases in which the final result of the periodontal treatment cannot be predicted with certainty at the time of initial treatment planing. Permanent splints are constructed to provide stability for teeth undergoing progressive tipping or for teeth that have lost so much of their periodontal support that they cannot carry out normal function if they are left as single units. All splints should enhance the stabilityy and function of the dentition. Temporary splints could be fixed, external types such as in the use of annealed stainless steel ligature wire (.010or .012 in.), single or double, bonded to the teeth facially, lingually, or even incisally. The splint of wire combined with acrylic is very effective. Other temporary fixed external type included orthodontic bands welded together (too cumbersome, poor esthetics), cast splints of gold or chrome nickel alloy cemented to the teeth and the facial and lingual parts tied together with ligatuer wire. The most popular temporary splint is the one made with acid etch, self polymerizing resin, and composite material. The acrylic can be reinforced with the orthodontic grid material or cast metal framework. Denture teeth can be used to substitute for the tooth or teeth missing and thus further increase the supporting periodontium. Long term benefits from splints is illlusory, since the teeth revert to its initial mobility when splint is removed.
Another type of temporary splint are the fixed internal type of which the teeth must be prepared with the interproximal box preparation with mark retention, then the teeth are held together with metal wires with acrylic reinforced. This type of appliance can be worn for up to 2 or 3 years.
Another type of temporary splint are the removable splint wich included the cast metal splint of Elbrecht, the acrylic Hawley or other types of orthodontic appliance, the bite guards or night guards. This type of splint is less stabilized than the fixed type, but provided better oral hygiene and convenience in construction.
In the case of diagnostic splint, a temporary external splints for teeth that have a reasonable good periodontal prognosis is recommended. The preferred technique is the acid etch technique.
The permanent splints included the fixed, semirigid, or removable splint with the use of anchorage internally or externally to the teeth. Fixed permanent splints is most recommended with utmost attention given to oral hygiene. Principles in its construction included elimination of all sources of gingival irritation, good access to oral hygiene, excellent retention in all abutment preparation, and adequate thickness or bulk of the splint and good solder joints. The use of semi regid or precision attachment connection can beused. Pin ledge type of abutment should be used for fixed splint whenever possible. The removable permanent splint included the use of telescoping crown and precision attachment to constructed a cast metal splints, clasped supported partial denture.
Glickman et al. (1961) evaluated the effects of splinting teeth in hyperocclusion using five Rhesus monkeys. The forces which applied to 1 tooth in a splint were transmitted to all teeth within the splint. The direction of the initial force was maintained and comparable areas of the splinted periodontium were affected. The bifurcation and bifurcation areas were most susceptible to excessive force. Forces applied to non-splinted teeth were not transmitted to adjacent teeth and force sufficient to cause necrosis did not cause pocketing.
Nyman et al. (1975) studied 20 patients who had originally exhibited severe periodontal breakdown and extensive tooth loss. Extensive fixed bridgework was placed following periodontal therapy and the patients monitored for 2 to 6 years. No further bone loss was observed between the insertion of the fixed bridgework and the final examination. The authors reported no increase in PDL width of the abutments or changes in mobility.
In summary, regardless whichever type of splint to be use, the rigidness, the oral hygiene, and stabilization of occlusion are the critical factors in the splint design. Common dysfunctional problem in splinting and oral rehabilitation are tipped abutment teeth which required uprighting with orthodontic appliance. It is also important that the splint be properly articulated in lateral excursion, allowing lateral movements with undue pressure on the splint. In the case of deep overbite, sufficient overjet must be provided so that lateral excursion are unrestricted. In patient with deep overbite and a markedly curved arch in the anterior region, maxillary incisors must be maintained for abutment, even if these teeth have extensive loss of support and appear very loose.
Disadvantage of splinting included gingival irritation, difficult oral hygiene access, interference of the splint to normal interproximal wear and mesial drift, crown become loose or fractured, interference with phonetics. With these disadvantage in mind, splinting should only be done when occlusal stability and adequate masticatory function desired. It should never be used to substitute occlusal adjustment therapy. Prognosis of the splinting teeth (tooth) relies greatly on oral hygiene achieved in the area.
Ramjford further describes the biomechanics of the splint. The reduction mobility is achieved by decreasing the occlusal forces to the mobile tooth through occlusal equilibration prior to splinting, and increasing the periodontal resistance with the inclusion of other teeth into the splint. Splinting allow better force distribution, directing the force to be distributed over the entire splinting area thus better periodontal support,and as a result of conditioned reflex activity, masticatory function is directed toward the area that most convenient and efficient for function. Lateral force or tipping forces should be avoided as much as possible. Functional contact should be in a straight line between the abutment of the splint in order to avoid tipping forces when biting forcefully. Mesial or distal force can be better distributed when two single rooted teeth are splint together. Intrusive forces are very well tolerated since their impact is spread over a maximal number of principal periodontal fibers. In order to achieve favorable a stabilization in the faciolingual and mesiodistal direction, a splint has to connect posterior and anterior segments or to engage teeth in the opposite side of the arch for support. Such a distribution of abutment produces the tripod effects: a tipping force acts as a well toleated intrusive force on one or more abutment. Fixed splint provided much greater stability than the removable appliances, and thus is recommended in splinting teeth with minimum residual support.
In summary, splint offered numerous therapeutic advantages ranging from increase periodontal resistances to occlusal relationship correction. Regardless of the type of splint design, material, and method of fabrication, it must provide good access to oral hygiene, rigid fixation, and also elimination of occlusal trauma by providing force distribution and resistance to occlusal overload.

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References

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