Application and trends in provisional dental restorative materials for fixed partial denture: An overview

Asmath Jehan; Ahila Singaravel Chidambaranathan; Muthukumar Balasubramanium

doi:10.4103/jorr.jorr_28_22

REVIEW ARTICLE

Year : 2023 | Volume : 15 | Issue : 1 | Page : 65-71

Application and trends in provisional dental restorative materials for fixed partial denture: An overview

Asmath Jehan, Ahila Singaravel Chidambaranathan, Muthukumar Balasubramanium
Department of Prosthodontics, SRM Dental College, Chennai, Tamil Nadu, India

Date of Submission	20-Jun-2022
Date of Decision	29-Jul-2022
Date of Acceptance	29-Jul-2022
Date of Web Publication	29-Dec-2022

Correspondence Address:
Ahila Singaravel Chidambaranathan
Department of Prosthodontics, SRM Dental College, Ramapuram, Chennai - 600 089, Tamil Nadu
India

Source of Support: None, Conflict of Interest: None

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DOI: 10.4103/jorr.jorr_28_22

Abstract

A provisional restoration must protect the prepared tooth, restore form and function which should be esthetically acceptable. Sometimes, they are made to assess the outcome of a specific therapy for definitive prosthesis. Hence, understanding the properties, manipulation methods, and uses of provisional restorative materials for fixed partial denture is essential for all dentists. The objective of the study was to assess the recent advancement in provisional restorative materials for dental prosthesis available now. Literature search on PubMed and Google Scholar was done from January 1965 to March 2022 using the keywords such as provisional and interim restorative materials. In addition, hand search was done through refereed dental journals for 2000 to 2022. Nanoparticle-reinforced provisional restorative materials for any fixed dental prosthesis had better mechanical properties compared to conventional provisional materials available in the market. Digitally fabricated provisional materials eliminate the impression and the laboratory fabrication procedures, so that it consumes less time for fabrication.

Keywords: Fixed dental prosthesis, polymethyl methacrylate, provisional restoration, temporary restoration

How to cite this article:
Jehan A, Chidambaranathan AS, Balasubramanium M. Application and trends in provisional dental restorative materials for fixed partial denture: An overview. J Oral Res Rev 2023;15:65-71

How to cite this URL:
Jehan A, Chidambaranathan AS, Balasubramanium M. Application and trends in provisional dental restorative materials for fixed partial denture: An overview. J Oral Res Rev [serial online] 2023 [cited 2023 May 31];15:65-71. Available from: https://www.jorr.org/text.asp?2023/15/1/65/365916

Introduction

Provisional dental restorations are an integral part in permanent dental prosthesis and dental implantology.^[1] Provisional dental prosthesis is fabricated to improve esthetics and mastication and phonetics for limited duration, then it will be replaced by a permanent dental restoration.^[2]

The use of provisional fixed dental prosthesis (FDPs) are for diagnostic purpose and enrichment of psychological uplift of patient whoever go for final restoration until the fixation of final restorations.^[3],[4] The provisional FDPs should protect pulp, preserve periodontal health, harmony with occlusion, maintaining the integrity of the arch, prevent tooth fracture, withstanding the occlusal loads, resistance to separation of forces, preserving the alignment of the abutment, easy to modify, color stability, and have sufficient translucency.^[5] Temporary prosthesis is subjected to masticatory loads in the oral cavity; hence, they are designed in such a way to withstand the heavy masticatory forces.^[6] The properties of provisional restorations are very important in certain clinical conditions such as full-mouth rehabilitation, long-span edentulous condition, and temporomandibular joint dysfunction.^[7]

The provisional restorative materials should protect the pulp, help to analyze the occlusion, incisal, or canine relation, relationship between tooth and gingiva and to maintain the teeth position, to restore masticatory function, esthetics, and phonetics.^[8] These properties of provisional materials are necessary to provide good health to supporting tissues after the definitive prosthesis.^[9]

The most common problems encountered during fabrication of provisional restorations are defects during fabrication or breakage in the mouth at the interim period due to parafunctional habits like bruxism or insufficient amount of tooth reduction during preparation phase.^[10] Furthermore, provisional restoration breaks in persons with parafunctional habits or less tooth amount of preparation. Hence, it is a daunting task to dentists in such clinical situations. Furthermore, evidence found that the repaired provisionals have low strength compared to original crown.^[11] Polymethyl methacrylate (PMMA) resin is the most commonly used material for making of provisional restoration due to favorable properties such as easy manipulation, light weight, inexpensive, good esthetic, and lack of inadvertent reaction.^[12] There are certain drawbacks with PMMA such as its poor strength, polymerization shrinkage, and color instability.^[13]

Therefore, it should have mechanical stability, durability, fracture, corrosion resistant, and dimensional stability. The acrylic resin dental prosthesis fractured during heavy masticatory forces or accidental; hence, enhancement in the mechanical properties have been brought by addition of reinforcing agents to PMMA matrix.^[14] Acrylic resin material is susceptible to surface dissolution leads to surface roughness changes which facilitate accumulation of microorganism which will invite infection and formation of denture plaque and biofilm. Modifications of the material are done by incorporation of fillers, which may improve the mechanical properties.^[15]

Lot of methods are available to enhance the properties of chemically activated PMMA resin such as heat posttreatment by hot water treatment or microwave postirradiation^[16] or the reinforcement with rods or particles to form a composite material which may show rise in mechanical properties compared to conventional chemically activated PMMA resin.^[17] Nanomedicine in health care reported that nanoparticles are not released from the unset materials. It also reported that risks for dentists and dental patients are very minimal.^[18] Nanoparticles are commonly used to improve the surface characteristics such as mechanical properties and wettability and prevent the penetration of microorganisms into the PMMA resin.^[19] They also reported that reinforcement with metal oxides and wires and glass fibers had improved the mechanical properties.^[20] This article critically analyzes the provisional materials for fixed partial denture and their fabrication techniques and their properties.

Revolutions in Provisional Restorative Materials

In 1965, stock crown was luted with thick consistency of zinc oxide and eugenol,^[21] and Donald et al. in 1971^[22] suggested an indirect technique for the construction of acrylic resin temporary restorations.

In 1988,^[23] Triad visible light-cured (VLC) material has the same mechanical properties but the abrasion resistance and wear resistance are higher than the conventional PMMA acrylic resin provisional crown as well as fixed partial denture, and recommended Triad VLC material fixed partial denture for patients sensitive to PMMA.

Gegauff et al. in 1995^[24] found that the fracture toughness for the wet and dry test environment of light-initiated urethane dimethacrylate resin was similar and had superior higher fracture toughness than the unfilled PMMA resin.

Hazelton in 1995^[25] proposed stainless steel orthodontic band for the reinforcement of provisional restorations for both short-span and long-span situations.

Lee et al. in 2002^[26] mentioned that the temperature used for polymerization of resin was the governing factor for improving hardness, but the water was the governing factor to reduce the residual monomer. The pressure used for flasking does not have any significant role on the properties of resin.

Neveen M. Ayad et al. in 2008^[27] mentioned that performance of fixed temporary prosthesis was improved after reinforcement of high-impact resin with zirconia powder.

Sodagar et al. in 2013^[28] suggested that the flexural strength of resin is grossly improved with the incorporation of nano-TiO₂ and SiO₂ particles.^{[29],[30],[31]} However, nanoclay material had pessimistic effect on the properties.^[32] The addition nano-ZrO₂ increase the tensile strength but the translucency of the PMMA resin was lessened,^[33] but the dimensional accuracy was raised and the impact strength decreased.^[34]

Oleiwi et al. in 2019^[14] concluded that the hardness and compressive strength were improved with concentrations of rice husk and bamboo powders.

Properties of Provisional Restoration

It should be made up of a biocompatible material
It should not elicit any allergic reactions in the oral cavity
Easy to manipulate and should have adequate working time
Strength to withstand the forces
Color should match with the adjacent tooth structure
It should be of adequate color stability and translucency.

Functions of Provisional Restoration

Biologic

Pulpal^[35] Protection: An interim fixed restoration should prevent the conduction of thermal extremes to the pulp and should seal and insulate pulp from sensitivity and irritation
Periodontal health: It should have proper marginal adaptation, normal contours, and polished surfaces to facilitate the health of gingival and periodontal tissues
Occlusal functions: It should have a proper contact with the adjacent teeth and proper occlusion with the opposing teeth. Improper contacts lead to supraeruption of the opposing teeth and horizontal movement of the adjacent teeth
Positional stability: The prepared tooth should not change in position, which needs modification or remake of the final restoration during luting
Prevention of enamel fracture: It should protect the teeth weakened by crown preparation.

Mechanical function

PMMA resins have strength about 1/20 of metal–ceramic alloys.^[35] Hence, to avoid failure or fracture, the connector size should be more in interim restoration compared to the definitive prosthesis.

Esthetic function

An essential requirement^[35] of prosthodontic treatment is that the shade of the material should be similar to the color of the adjacent teeth. To achieve optimum esthetics, shade guides are used for the selection of shades for final restoration.

Classification of Provisional Restoration

According to method of fabrication

Preformed crowns

Resin: Cellulose acetate,^[35] polycarbonate, photopolymerized composite resin
Metal: Aluminum, tin–silver, nickel–chromium, and stainless steel.

Custom-made

Direct technique: Base plate wax technique, shell-fabricated technique, and template-fabricated technique
Indirect technique: Template-fabricated provisional restoration, overimpression-fabricated provisional crown, overimpression-fabricated bis-acryl composite provisional, template-fabricated VLC provisional restoration, and shell-fabricated provisional restoration
Direct and indirect combination
Digital technique.

According to period of use

Long term and short term.

Fabrication of Provisional Restoration

Prefabricated crowns

Prefabricated crowns are aluminum cylinders, anatomic metal crowns, clear celluloid shells, and polycarbonate tooth color crowns. Prefabricated crowns are preferred for single crown because the topography of the crowns is not suitable to use them as pontics for FDPs. They are made up of nickel–chromium, aluminum, tin–silver, cellulose acetate, and polycarbonate materials and marketed in different forms and sizes.

Polycarbonate crown

Polycarbonates are available for anterior and premolar tooth. It provides lifelike appearance to the preformed crowns. When appropriately selected crowns reveal better appearance than a porcelain restoration. However, it is available only in single shade.

Cellulose acetate

Cellulose acetate is a lean (0.2 mm to 0.3 mm) crown, which is transparent supplied in all tooth forms and various sizes. The shades are entirely dependent on the resin used for fabrication, but the crown is mechanically bond; therefore, after polymerization, the shell can be removed and replaced in the case of staining or color change. Due to the necessity to remove the shell, resin to be added on the proximal side to establish the tooth contacts.

Aluminum and tin–silver

Anatomic form has anatomically shaped aluminum crowns with occlusal and axial surfaces. The cylindrical shells are cheap, but they must be modified to reach acceptable occlusal and axial forms. They are available in different shapes and sizes, which is suitable for unesthetic area. Tin–silver crown permits expansion of cervix to fit into the tooth closely and highly ductile alloy. The fracture of the finish line area is occurred in feather edge finish line when the metal crown is fixed over the prepared tooth.

Stainless steel crown

Stainless steel crowns are used for extensively damaged primary teeth in children. Because of its hardness, they can be used for longer term. They may be used for permanent dentition, but more ideal for deciduous dentition. They are available in different forms and sizes, but the crowns with straight and contoured axial surfaces are mainly for deciduous dentition.

Custom-made crowns

Custom-made direct technique

They are made directly on prepared tooth which is very technique sensitive in which a mold or matrix is made from the diagnostic wax-up from a preoperative cast. The matrix is seated on the tooth preparation, and then the teeth are cleaned and lubricated with petroleum jelly. Then, mix the provisional material and poured into matrix then placed on the prepared teeth and permitted to cure. The restoration should be removed before complete polymerization and permitted curing outside the mouth, which protects the pulp from thermal injury or adhesion of the provisional restoration on the prepared tooth. PMMA resin restorations cannot be removed at this stage since they undergo polymerization shrinkage. However, bis-acrylic resins have less polymerization shrinkage and on-off method is proposed to avoid interlocking of the provisional restoration with the teeth.

However, this method showed relatively poor marginal integrity and practically the provisional restoration is very difficult to remove if there is any proximal undercut on the adjacent teeth. The direct technique is preferred for single crowns and short-span fods because it consumes less time and materials. The freshly cut dentin and pulps are subjected to exothermic heat during polymerization and free monomer or other irritating chemicals.

Base plate wax technique

Matrix can be a baseplate wax because it is convenient, but it is not adapted easily with precision and requires more time for adjustment.

Template-fabricated provisional fixed partial denture

A thermoplastic template is poured with provisional restorative resin and seated on the prepared teeth. The templates are dimensionally; hence, they adapt better when checking for preparation.

Shell-fabricated provisional restoration

A thin provisional crown is fabricated from chemically activated PMMA resin in an impression before preparation. The fitting surface is modified on the day of preparation by dripping monomer and gently blowing polymer after the tooth preparation. A spare shell can also be prepared from the same impression which can be heat processed in a laboratory. Furthermore, shell can be made of polycarbonate by direct technique.

Custom-Made Indirect Technique

Overimpression-fabricated provisional crown

Before tooth preparation, an overimpression is made in the mouth or on the diagnostic cast. For making impression, hydrocolloid (alginate) impression materials are more popular because of its availability in the dental operatory. After the tooth preparation, sectional impression to be made with alginate and make a cast with dental plaster. Then, try the finished plaster cast in the overimpression to verify the fitness of the impression over the cast. Tin foil substitutes are used to cover the prepared tooth and adjacent areas of the cast and allow them to dry before mixing of the PMMA provisional resin. Manipulate tooth-colored PMMA provisional resin in a dappen dish and poured into the overimpression till it completely fills the prepared crown. Then, the excess resin had to removed and keep the cast with the overimpression in place with rubber band. When the resin has polymerized, separate the cast from the overimpression. If any difficulty is found during removal, break the tooth in the plaster cast and retrieve it. Then, finish the provisional restoration with the acrylic burs.

Template-fabricated provisional fixed partial denture

A template is formed from clear thermoplastic resin using a vacuum forming machine. The provisional PMMA resin is poured into the template and seat on the prepared teeth or on the prepared cast of fast-setting plaster. Templates are very stable and easily adapt to the working cast for verifying the amount of tooth reduction.

Template-fabricated visible light-cured provisional restoration

A VLC resin transparent template is essential to permit the light to access the resin to initiate polymerization. A template is formed with the help of a vacuum forming machine. Manipulate the silicone impression putty impression material and mold and adapt it around the template on the cast to prevent displacement of the viscous resin.

An impression of the prepared tooth is made with alginate and pour with dental plaster. Then, coat the surface of the cast with a layer of model releasing agent. Then, pour the impression with Triad resin around the finish lines then the surrounding areas. To enhance esthetics, translucent resin is filled into the incisal or occlusal part and use the finger pressure to keep the filled template and the cast in the Triad curing unit for 4 min for polymerization. Carefully separate the provisional restoration and place it with tissue side up for an additional 6 min in the same curing unit. Retrieve the provisional restoration and trim the excess material with curved scissors and finish the axial surfaces to the margins with discs.

Shell-fabricated provisional restoration

It is made from chemically activated PMMA resin in a diagnostic impression before the preparation appointment. Then, add monomer gently and blow the polymer with an atomizer. The fitting surface is relined with resin after tooth preparation. A spare shell can be made from the same impression, which can be heat processed in a laboratory.

Overimpression-fabricated bis-acryl composite crown

Bis-acryl composite resin polymerization reaction produces very less heat and minimum adverse effect on soft tissues and the pulp. Hence, it is selected for direct and indirect technique.

Indirect–Direct Technique

A combination of direct and indirect method is advocated to provide rapid and nontraumatic way of making a close-fitting provisional restoration.^[10] The hollow thin shell fabrication was made indirectly on a minimally prepared cast of the future planned restorations. The fitting surface of the shell is relined with the provisional resin inside the patient's mouth. It provides good marginal adaptation and least thermal injury to the pulpal tissues. However, indirect–direct technique is time-consuming and need laboratory support compared to indirect method of fabrication of provisional restoration.

Materials Used as Provisional Restorative Resin

Chemically activated polymethyl methacrylate

In 1940, chemically activated PMMA resin was introduced. They have good wear resistance, good esthetics, good color stability, and cost-effective. However, they released a significant amount of exothermic heat during polymerization reaction. They have shrinkage of about 8%, objectionable odor, less working time, poor color stability, and difficult to repair.^[36]

Heat-activated polymethyl methacrylate

They have good strength and fracture resistance, which is suitable for long-term temporary restoration. Due to heat, more amount of contraction on cooling the dental flask and tedious lab procedure than other methods of activation; hence, heat-activated PMMA resin is usually not used for making provisional restorations.

Poly-R' methacrylate (R' = ethyl, vinyl, isobutyl)

They are cost-effective, the amount of heat release is minimal while polymerization which leads to less shrinkage than polymethyl methacrylate. They have prolonged working time and radiolucent. However, they are less esthetic than other newer provisional materials. The eugenol in the luting agent deteriorates the resin, which leads to less wear resistance, less color stability, inadvertent odor, and difficult to repair.

Epimines

They are two-paste type of acrylic resin introduced in 1968 in dentistry as Sutan (ESPE). They have low shrinkage, less amount of heat production, and least pulpal irritability, but they have least strength and cannot be modified.

Composite resin

Most of the provisional materials are bis-acryl resin. This kind of resin is usually mixed with inorganic radiopaque filler that is similar to composite restorative resin. They are available in autopolymerized, dual-polymerized, and visible light-polymerized resin forms.

Autopolymerizing composite resin

Chemically activated resin available in two pastes system where an aromatic tertiary amine is the activator (e.g., N, N-dimethyl-p-toluidine) and the initiator is benzoyl peroxide. Today, these materials are mainly used for restorative purpose in dentistry. The shrinkage is very minimal, release less heat, good esthetics, minimal odor, and easily polishable at the clinic. The major drawback was air incorporation when mixing, which leads to porosity.

Visible light-cured resin

It was introduced in the 1980s and they require urethane dimethacrylate resin where the curing is initiated with camphorquinone/amine photo. (400 and 500 nm) and activated with visible light. Light-cured composite resins are available in light-proof syringe single-paste system. The ingredients can be mixed by the manufacturer with little porosity, and working time is infinite because no setting occurs if the material is kept in a dark environment. But the depth to which visible light can penetrate (less for darker materials).

Dual-polymerizing composite resin

Dual-polymerizing composite resin materials are combination of chemically polymerized bis-acryl and light-polymerized urethane dimethacrylate resins. The curing depth is better than light-cured resin, it is not used in cementation of bulky ceramic inlays and porosity are problems with dual-cure resins.

Recent Advances in Provisional Restorative Material

Most of the commonly used resin materials are brittle.^[24] Repair and replacement of the fractured provisional restorations is major concern for both dentists and lab technicians in case of long-span restorations. Because the survival rate depends on the resistance of the material to crack propagation^[24],[37] which may occur due to poor mechanical properties.^[38] Combination of resin and metal castings and swaged metal substructures are very useful for long-term or long-span interim restoration.^[37] The commonly used materials for reinforcement have had little or no effect in the strength of the resin.^[39],[40] The use of fillers is an effective method to increase the fracture toughness of provisional restoration resins.^[41]

Nanoparticle Incorporation

Zirconium oxide, aluminum, and titanium nanoparticles were added to unfilled methyl methacrylate resin to facilitate strength of the resin matrix by interrupting crack propagation, which tends to increase the modulus of elasticity, transverse strength, toughness, and hardness.^[42],[43] The incorporation of SiO₂ nanoparticles into autopolymerized polymethyl methacrylate resin is helpful for improving the flexural modulus and strength.

Digital interim fixed restoration

Nowadays, interim restorations can be made using digital workflow using PMMA and composite. During tooth preparation the digital information are sent to a milling machine and the tissue surface form (TSF) and external surface form (ESF) are milled from solid blocks/disks of resin. The pros of computer-aided design/computer-aided manufacturing process are it reduces the patient's exposure to chemicals, stronger and more accurate than traditional bis-acryl composite resin restorations. Hence, the prosthesis can be given on the same-day computer aided designing/computer aided manufacturing (CAD/CAM) restorations.

Conclusion

The most predictable aspects of dental profession are to provide a satisfied outcome to the patient to any kind of oral rehabilitation in which the provisional restoration had a critical role before any kind of final prosthesis. Fabrication of an accurate provisional restoration requires more time and effort. The future research should focus on technological advancements to provide a provisional material good biocompatibility, improved physical properties, and esthetically pleasing.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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