This prospective clinical pilot study evaluated the performance of fibre-reinforced-composite resin (FRC) splints on mandibular anterior teeth.
Between June-2003 and January-2008, 19 patients (7 females, 12 males, 45–72 years old) from a group of consecutive patients who completed periodontal therapy received E-glass FRC splints (everStick Perio, StickTech) in combination with two types of flowable and restorative resin-composites (Filtek Flow, Filtek Supreme, n = 11; Tetric Flow, Tetric-Ceram, n = 8). Only patients with vital teeth, presenting mobility of grade 3, having at least one canine with no mobility on both sides of the dental arch were assigned for a splint therapy. The patients were recalled for periodical follow-up controls first at 6 months and thereafter annually. The evaluation protocol involved technical failures [chipping, debonding or fracture (tooth/restoration)] and biological failures (caries)]. Periodontal pocket depth (PPD) and clinical attachment level (CAL) were measured 6 months after splinting and annually. Six sites were measured for each natural tooth at the mesiobuccal, buccal, distobuccal, distolingual, lingual and mesiolingual sites.
All splints were applied from canine to canine in the mandible. In total, 5 recalls were performed and no drop-out was experienced. One partial debonding of the FRC splint with Tetric Flow/Tetric-Ceram combination was observed after 40 months. No caries was found around any of the splints and no teeth had to be extracted until the final follow up. The splinted teeth were found to be vital in the vitality tests. Overall survival rate was 94.8% (Kaplan–Meier). The survival rate was not significantly affected by the composite type (Filtek-Flow/Filtek Supreme: 100%, Tetric Flow/Tetric Ceram: 96% ( p = 0.92) [Kaplan–Meier, Log Rank (Mantel–Cox) (CI = 95%)]. Hazard ratio for Tetric Flow/Tetric Ceram group was 0.05 (95% CI) and for Filtek Flow/Filtek Supreme group 0.00 (95% CI). Whilst overall PPD measurements of the dentition ranged between 6 and 12 mm, the CAL measurements ranged between 4.9 and 10 mm at baseline. The mean PPD for the splinted teeth decreased from 8.9 ± 1.8 mm to 5.2 ± 1.2 mm, and CAL decreased from 7.2 ± 1.6 mm to 4.6 ± 1 mm at the end point.
Direct tooth splinting with E-glass FRC material performed successfully up to 4.5 years. Periodontal status of the splinted teeth showed decreased PPD and CAL.
Teeth are splinted and stabilized in the anterior or posterior regions of the mouth for a variety of reasons. Clinical situations that require tooth stabilization include mainly orthodontic retention, repositioning or re-implantation of the avulsed teeth that were subjected to trauma, splinting teeth in primary or secondary occlusal trauma, and periodontal splinting of the severe mobile teeth after elimination of the periodontal disease. However, not every mobile tooth should be splinted and the duration for splinting could be short-term or long-term depending on the situation. For splint applications, biological and biomechanical principles should be considered in a multidisciplinary approach.
The main objectives of splinting teeth in patients with advanced periodontal problems are to achieve periodontal healing, create an oral environment in which tooth mobility is at a tolerable level or at least no longer increasing and the patient is able to function comfortably. Often such patients avoid chewing on or incising food with such mobile teeth, yielding to soft diet restrictions.
Splints in dentistry are classified as provisional or permanent and they may be either fixed or removable. They may be constructed of various materials being as simple as a bonded composite resin button connecting one tooth to the other allowing better cleanability of the teeth. Yet, this type of stabilization is considered transient in nature, due to the inability of composite resin to accommodate shear forces.
Several clinical studies in the field of orthodontics reported high debonding rates when the mandibular or maxillary teeth are splinted with the use of metal wires. Although the reason for these failures are not well studied, several factors are described in the dental literature such as insufficient composite material and/or abrasion of the composite, less abrasion resistance and wear as a consequence of chewing or tooth-brushing, thickness of the wire and intermittent forces of mastication. Another reason for debonding rates was attributed to the forces resulting from tension in the wire or between the wire and the teeth when the wire has not been adapted properly to the surface of the teeth. Nevertheless, detachment of the bonded wire retainers may have negative consequences for the treatment result, possibly making re-treatment necessary. In fact, teeth without mobility are splinted in orthodontics after the end of the orthodontic treatment to avoid relapse response of the teeth to their original positions, whereas in peridontally compromised patients, usually splinting is achieved on mobile teeth at various grades. In that respect, theoretically, resin-impregnated fibre-reinforced-composite resin (FRC) materials are well suited for stabilizing hyper-mobile teeth that interfere with chewing function because of their elastic modulus, aesthetics, pliability, and the possibility of chemical adhesion both to the composite materials and the tooth, as opposed to the metal wires.
Resin pre-impregnated FRCs has suitable flexural modulus and flexural strength to function successfully in the mouth as restorative materials. It is considered that elimination of the metal wire in the retainer by using FRC systems would lead to more stable bonding since adhesion of such retainers would solely rely on adhesion of the flowable composite or the resin matrix of the FRC to the etched and bonded enamel. Pre-impregnated FRC systems usually involve monomers such as urethane dimethacrylate (UDMA), urethane tetramethacrylate (UTMA), bisphenol glycidylmethacrylate (Bis-GMA) or polymethylmethacrylate (PMMA). Evidence still lacks whether ultra high molecular weight polyethylene (UHMWPE) fibres could be used to fabricate durable FRC restorations. Criticism has been focused on the inadequate interfacial adhesion between polyethylene fibres and dental polymers, compared to glass fibres that can be silanized.
Development of silanized and resin-impregnated, FRC materials has provided the potential new approaches for stabilizing hypermobile teeth or replacing teeth in a conservative manner. Unfortunately, no long-term clinical study is available to date with such FRCs used for splinting purposes. Therefore, this pilot study evaluated the clinical performance of FRC splints on the anterior mandibular teeth in the periodontal treated patients.
Materials and methods
In this prospective clinical study, between June 2003 and January 2008, 19 patients (7 females, 12 males, minimum age: 45, maximum: 72 years old) received FRC splints at the Ege University, Dental School, Department of Prosthodontics, Izmir, Turkey, after signing the appropriate informed consent form approved by the Ethical Committee of the University Institutional Review Board (vote number of the local Ethical Committee No.: 7OM/743). The subjects were not admitted to the study if any of the following criteria were present: (1) younger than 18 years old, (2) not able to read and sign the informed consent document, (3) physically and psychologically not normal, (4) having general health-compromising conditions, (5) pregnant or had a history of ectopic pregnancy, (6) undergoing active periodontal and/or orthodontic therapy, (7) an impaired response to infection, (8) using tooth whitening dentifrices, (9) smokers, (10) missing teeth in the splinting area, (11) history of endodontic therapy and/or any restoration on the teeth to be evaluated, (12) residence outside the city where the study was conducted, insufficient address for follow-up, or unwillingness to return for follow-up as outlined by the investigators.
All restorations were made directly by one operator using unidirectional E-glass fibres (everStick Perio, StickTech) in combination with two types of flowable and resin composites (Filtek Flow, Filtek Supreme, 3M ESPE, n = 11; Tetric Flow, Tetric Ceram, Ivoclar Vivadent, n = 8). The resin composite materials were standard materials of the clinic and they were applied based on the availability of the system in our clinics. Materials used for this study are listed in Table 1 .
|Brand name||Composition||Manufacturer a||Batch number|
|everStick ® Perio||E-glass/PMMA/Bis-GMA||StickTech Ltd., Turku, Finland||000088|
|Heliobond ®||Monomer matrix: dimethacrylate, <60% Bis-GMA, <40% triethyleneglycol||Ivoclar Vivadent, Schaan, Liechtenstein|| H29583
|Tetric Flow ®||<14% Bis-GMA, <8% triethylene glycoldimethacrylate, <15% urethanedimethacrylate||Ivoclar Vivadent, Schaan, Liechtenstein|| J01476
|Tetric Ceram||Dimethacrylate-based monomers (17–18% weight), barium glass, ytterbium trifluoride, mixed oxide and prepolymer containing fillers (82–83% weight), additives, catalysts, stabilizers and pigments (<1.0% weight)||Ivoclar Vivadent, Schaan, Liechtenstein|| J10519
|Adper Single Bond Plus||Bis-GMA, HEMA, dimethacrylates, ethanol, water, photoinitiator system, methacrylate functional copolymer of polyacrylic and polyitaconic acids, 5 nm silica particles||3M ESPE, St. Paul, MN, USA||7KM|
|Filtek Supreme||Bis-GMA, Bis-PMA, TEGDMA, UDMA, silica and zirconia nanofiller||3M ESPE, St. Paul, MN, USA||8RB|
|Filtek 250||Bis-GMA, Bis-EMA, UDMA, silica and zirconia particles||3M ESPE, Minnesota, St. Paul, MN, USA||6ST|
a Information according to each manufacturer’s material safety sheet data (everStick Perio, StickTech Ltd., 20.05.2008, Nr. 100002; Heliobond, Ivoclar Vivadent, 27.09.2007, Nr. 1142; Tetric Flow, Ivoclar Vivadent, 01.10.2007, Nr. 1667; Tetric Ceram, Ivoclar Vivadent: 07.07.2011, Nr. 1907/2006/EC; Adper Single Bond Plus, 3M ESPE, 30.03.2004, Nr. 18-9025-0; Filtek Supreme, 3M ESPE, 02.11.2004, Nr. 18-0179-4).
From a group of consecutive patients, those who had undergone periodontal therapy with root planning and scaling procedures followed by clinical follow-up controls on a periodical basis and reached a stable hygiene phase, have been selected. All clinical periodontal status measurements were performed by an experienced periodontist. All patients were using manual toothbrush, were able to practice the use of dental floss and interdental brushes at the stabilized hygiene phase. In the selected group of patients, splinting was indicated due to severe mobility and lack of chewing comfort reported by the patients, at the Periodontology Department of the Dental School. Only patients with vital teeth, presenting mobility of grade 3 and having at least one canine with no mobility on both sides of the dental arch were assigned for a splint therapy.
After providing informed consent, the teeth on the labial and lingual surfaces were cleaned with pumice using a prophylaxy brush on a slow-speed hand-piece at 3000 rpm. All splints were made under rubber-dam. In order to avoid excess of adhesive resin or resin composite, orthodontic elastic bands (Wedjets, Coltène/Whaledent AG, Altstätten, Switzerland) were placed at the interdental spaces between the teeth to be splinted after placing the rubber-dam. With small amounts of resin composite (Filtek™ Z250, 3M ESPE), all mobile teeth were temporarily attached to each other at their labial surfaces and photo-polymerized (Demetron LC, SDS Kerr, Orange, CA, USA; light intensity: 600 mW/cm 2 ) for 10 s. The purpose of this step was to stabilize the mobile teeth and to avoid any displacement during splinting. For this process, the enamel surfaces were not etched and no surface preparations were made.
Enamel surfaces on the palatal side were then etched with 37% orthophosphoric acid for 60 s. After rinsing with water and air-drying, the corresponding intermediate adhesive resin was applied onto the surfaces using a microbrush, gently air-dried and photo-polymerized for 20 s. A thin layer of flowable composite resin was applied on the enamel surfaces and left unpolymerized. Then, previously measured length of FRC material was placed in the bed of the flowable resin with the aid of a silicone mould available in the FRC kit (Silicone Refix, Stick Tech, Finland). The silicone mould with the FRC material in its groove in the middle was exerted onto the lingual surface of the tooth on the flowable resin with gentle pressure. In the cases where the tooth was lingually positioned in relation to the neighbouring teeth, the silicone mould was pressed not only on the lingual but also at the approximal sites to achieve continuous alignment of the FRC. FRC together with the flowable composite was photo-polymerized for 40 s per tooth surface. Whilst polymerization on each tooth, the rest of the silicone mould was protected from the polymerization device with a metal hand instrument. When the whole FRC was polymerized, the silicone mould was removed and the exposed surfaces of the FRC were covered by the same flowable composite and photo-polymerized again for 40 s.
All FRC splints were made with one bundle of FRC material, their surfaces were completely covered with resin composite and each layer was again photo-polymerized for 40 s from all aspects. Finally, after occlusal adjustments, all FRC splints were finished using fine diamond burs (model number 012; Intensiv, Grancia, Switzerland) to remove the excess resin composite. Subsequently, the composite surfaces were polished with coarse, medium, fine, and ultrafine finishing disks (Sof-Lex, 3M ESPE) in sequence using with a hand-piece at 3000 r.p.m. in order not to expose fibres.
Oral hygiene protocols, the use of interdental brushes and flosses were practised once more and the patients were recalled for periodical follow-up controls first at 6 months and thereafter annually. Periodontal health, tooth mobility, level of oral hygiene and the condition of FRC splint in all patients were assessed during the follow-up controls according to the written protocol. Patients were informed about possible complications and instructed to call upon experience of a failure that could occur until the actual annual follow-up appointment. The evaluation protocol involved technical failures [chipping, debonding or fracture (tooth/restoration)] and biological failures (caries)]. On the periodontal aspect, periodontal pocket depth (PPD) and clinical attachment level (CAL) were measured 6 months after splinting and thereafter annually. Six sites were measured for each natural tooth, one each at the mesiobuccal, buccal, distobuccal, distolingual, lingual and mesiolingual sites encircling the tooth. Clinical attachment level refers to the distance between the cement–enamel junction and the base of the sulcus.
Survival time was calculated starting from the date of FRC splint placement to the end of the follow-up period. Survival analyses were performed with statistical software program (SPSS 13.0; SPSS Inc., Chicago, IL, USA) using Kaplan–Meier and Log Rank (Mantel–Cox) tests at a significance level of 0.05 to evaluate results versus time.
All splints were applied from canine to canine in the mandible. In total, 5 recalls were performed and no drop-out was experienced. One partial debonding of the FRC splint in the group with Tetric Flow/Tetric-Ceram combination was observed after 40 months. It was repaired using the CoJet system (3M ESPE) with Filtek Supreme composite and remained functional until the final observation date. Life-tables calculated from the data and Kaplan–Meier curves revealed an overall survival rate of 94.8% after 4.5-year observation time ( Fig. 1 ). The survival rate was not significantly affected by the composite type (Filtek-Flow/Filtek Supreme: 100%, Tetric Flow/Tetric Ceram: 96% ( p = .92) [Kaplan–Meier, Log Rank (Mantel–Cox) (CI = 95%)]. Hazard ratio for Tetric Flow/Tetric Ceram group was 0.05 (95% CI) and for Filtek Flow/Filtek Supreme group 0.00 (95% CI).
No caries was found around any of the splints, no teeth had to be extracted until the final follow up. The splinted teeth were found to be vital in the vitality tests. Patient compliance and satisfaction was very high.
The overall PPD measurements of the dentition ranged between 6 and 12 mm at baseline ( Fig. 2 ). The mean PPD for the splinted six mandibular teeth was 8.9 ± 1.8 mm at baseline and at final control of the splint treatment it was decreased to 5.2 ± 1.2 mm. The CAL measurements for the overall dentition ranged between 4.9 and 10 mm at baseline ( Fig. 2 ). CAL also decreased for the splinted teeth from 7.2 ± 1.6 mm to 4.6 ± 1 mm at the end point ( Fig. 3 ).
Except one incidence that was repaired using the silica coating and silanization method and remained functional during the observation period, the results of this study were very promising with both flowable and resin composites in combination with the FRC system employed. Most probably etching enamel and adhesive application was sufficient to achieve good adhesion of the flowable resin and thereby the whole FRC splint. Hence, both flowable and resin composite combinations used could be suggested for periodontal splinting. Today, repair actions using surface conditioning methods and resin composites prolong the survival of resin-based restorations. Therefore, restorations that remain functional for many years after repair procedures cannot be considered as catastrophical failures.
Dental literature contains information on FRC splint construction in case reports but longitudinal studies are limited or they report only short-term results. One such study presented 1-year follow-up of functional rehabilitation of a patient with severely advanced, rapidly progressing marginal bone loss treated by using the same FRC material used in this study. However, periodontal findings were only descriptive. In another clinical study, periodontal outcome of stabilized mobile teeth with an E-glass fibre (Fibre-Kor) was assessed. In that study, 56 patients were enrolled which is higher than that of this study. The study presented the results only after 10 months where PPD decreased by an average of 0.58 mm after teeth stabilization. PPD decrease in this study between 6 months and 18 months observations was an average of 1.2 mm. Additional information is needed whether this is due to the limited number of patients in this study or the difference in FRC materials used.
Since this study was not conducted in a larger population of patients, it could be considered as a pilot study. The patients retrieved for this study did not always have at least one canine with no mobility one one side of the mandible or did not report any chewing discomfort after after periodontal therapy which resulted in exclusion of many patients resulting in less number of patient enrolment. One tooth support with no mobility was amongst the selection criteria in order to provide a stable construction. The lack of mechanical failures in the group of Filtek-Flow/Filtek Supreme, and occurrence of no caries did not make it possible to calculate the power and consider multifactorial statistical design. Future studies on larger populations should verify the results of this study with the use of the studied resin composites in conjunction with the FRCs.
The thickness of the FRC-flowable resin complex may affect the longevity of the splints. From the mechanical point of view, FRC reinforced splints should be evaluated differently than those of bridge constructions. Static compression tests demonstrated that with the increasing fibre content, the flexural strength increases linearly. Such information is often derived from bar shaped specimens prepared according to the ISO norms where usually 2 mm of veneering composite was placed on the FRC material. Considering the geometry of the periodontal splints clinically, this thickness may not be favourable due to the added thickness of the splint, which may lead to plaque accumulation or disturbance with the occlusion. Since the construction should not exceed 2 mm, the FRC could even weaken the fibre/composite complex. The required thickness of the fibre–composite complex could be reached when box or groove preparations are made in the lingual surfaces. However, this would then not fit in the minimal invasive treatment approach. For this reason, in this study, no mechanical retentions or preparation were made on the enamel surfaces. In clinical practice, the complete thickness of the whole complex in a splint could still be considered high. The dilemma however remains how to control the thickness of the bonded retainers clinically. In this study, the thickness of the flowable composite covering the FRC splint was controlled manually. Whether the thickness of the composite impairs the survival of the splints needs to be analysed. Failed splints need to be evaluated also from this aspect in the future.
Because E-glass FRC has great aesthetic and economic superiorities, are easy to repair and require no preparation on sound teeth, they present an alternative treatment choice over other invasive restorative procedures. However, it should not be forgotten that fabrication of FRC requires a meticulous work. Splinting affords no guarantee that occlusal stress can be completely eliminated. Although extraction is an appropriate treatment for extremely mobile teeth, it may not resolve all the underlying pathology if the aetiology of the mobility is not established in the first place. Considering the clinical failures with stainless steel retainers related to debonding, especially the adhesion aspect warrants the comparison of FRC materials to their metallic counterparts clinically. When the metal wire is bended and placed on the lingual surfaces of the teeth to be splinted, the initial contact with the etched enamel is the wire itself. This may then act as debonding sites for crack initiation. This kind of phenomena is not valid for the FRC splint since mainly the flowable composite is in contact with the bonding agent treated enamel providing more reliable adhesion. Nonetheless, randomized controlled clinical trials would be conducted to compare whether FRCs have advantages over metal wires. It should however be noted that metal wires requires usually impression making and bending on the wires on the plastic model whereas, FRC splints do not require such clinical steps as they can be bonded directly at one session.
The patients treated in this study, presented high tooth mobility that impaired their chewing comfort. When other treatment options have been discussed with the patients, mainly due to economical reasons, fear from operations or simply for the sake of keeping their natural teeth as long as possible, splinting was decided. Moreover, splinting is considered as the primary standard care in the Periodontology Department where this study was pursued. These were the main rationale for keeping the splints even after the end of the observation period. Patients are being monitored for a longer duration.
No randomization was practised in this study and only one operator made the splints. Handling properties of one of the two flowable and composite resin combinations used might have been more favourable over the other that may eventually lead to bias. However, since only one failure was experienced, such a statement could not be made. Both flowable resins and their corresponding composite resins seem to perform equally well. In the absence of long-term clinical studies on the use of FRC materials as periodontal splints in the dental literature so far, this study may still serve some degree of evidence.
Direct tooth splinting with unidirectional E-glass FRC material performed successfully with an overall survival rate of 94.8% up to 4.5 years. Periodontal status of the splinted teeth also showed decreased periodontal pocket depth and clinical attachment level.
1. Dahl E., Zachrisson B.U.: Long term experience with direct bonded lingual retainers. Journal of Clinical Orthodontics 1991; 25: pp. 619-630.
2. Lumsden K., Saidler G., McColl J.: Breakage incidence with direct bonded lingual retainers. British Journal of Orthodontics 1999; 26: pp. 191-194.
3. Lie Sam Foek D.J., Özcan M., Verkerke G.J., Sandham A., Dijkstra P.U.: Survival of bonded stainless steel lingual retainers: a historic cohort study. European Journal of Orthodontics 2008; 30: pp. 199-204.
4. Hinckfuss S.E., Messer L.B.: Splinting duration and periodontal outcomes for replanted avulsed teeth: a systematic review. Dental Traumatology 2009; 25: pp. 150-157.
5. Serio F.G.: Clinical rationale for tooth stabilization and splinting. Dental Clinics of North America 1999; 43: pp. 1-6.
6. Vogel M., Deasy M.: Tooth mobility: etiology and rationale of therapy. New York State Dental Journal 1977; 43: pp. 159-161.
7. Lemmerman K.: Rationale for stabilization. Journal of Periodontology 1976; 47: pp. 405-411.
8. Nymann S.R., Lang N.P.: Tooth mobility and the biological rationale for splinting teeth. Periodontology 2000 1994; 4: pp. 15-22.
9. Nathanson D.: Posterior splinting with composite and wire. Compendium of Continuing Education in Dentistry 1981; 2: pp. 71-74.
10. Bearn D.R.: Bonded orthodontic retainers: a review. American Journal of Orthodontics and Dentofacial Orthopedics 1995; 108: pp. 207-213.
11. Bearn D.R., McCabe J.F., Gordon P.H., Aird J.C.: Bonded orthodontic retainers: the wire–composite interface. American Journal of Orthodontics and Dentofacial Orthophedics 1997; 111: pp. 67-77.
12. Foek D.L., Özcan M., Krebs E., Sandham A.: Adhesive properties of bonded orthodontic retainers to enamel: stainless steel wire vs fiber-reinforced composites. Journal of Adhesive Dentistry 2009; 11: pp. 381-390.
13. Strassler H.E., Haeri A., Gultz J.P.: New-generation bonded reinforcing materials for anterior periodontal tooth stabilization and splinting. Dental Clinics of North America 1999; 43: pp. 105-126.
14. Meiers J.C., Duncan J.P., Freilich M.A., Goldberg A.J.: Preimpregnated, fiber-reinforced prostheses. Part II. Direct applications: splints and fixed partial dentures. Quintessence International 1998; 29: pp. 761-768.
15. Freilich M.A., Meiers J.C., Duncan J.P., Goldberg A.J.: Fiber-reinforced composites in clinical dentistry.1999.Quintessence Pub.Chicago p. 9–21
16. Gutteridge D.L.: Reinforcement of poly(methyl methacrylate) with ultrahigh-modulus polyethylene fiber. Journal of Dentistry 1992; 20: pp. 50-54.
17. Vallitu P.K.: The effect of glass fiber reinforcement on the fracture resistance of a provisional fixed partial denture. Journal of Prosthetic Dentistry 1998; 79: pp. 125-130.
18. Sewón L.A., Ampula L., Vallittu P.K.: Rehabilitation of a periodontal patient with rapidly progressing marginal alveolar bone loss: 1-year follow-up. Journal of Clinical Periodontology 2000; 27: pp. 615-619.
19. Tokajuk G., Pawińska M., Stokowska W., Wilczko M., Kedra B.A.: The clinical assessment of mobile teeth stabilization with Fibre-Kor. Advanced Medical Sciences 2006; 51: pp. 225-226.
20. Hickel R., Roulet J.F., Bayne S., Heintze S.D., Mjör I.A., Peters M., et. al.: Recommendations for conducting controlled clinical studies of dental restorative materials. Science Committee Project 2/98 – FDI World Dental Federation study design (part I) and criteria for evaluation (part II) of direct and indirect restorations including onlays and partial crowns. Journal Adhesive Dentistry 2007; 9: pp. 121-147.
21. Narva K.K., Lassila L.V., Vallittu P.K.: The static strength and modulus of fiber reinforced denture base polymer. Dental Materials 2005; 21: pp. 421-428.