Wear Behavior of Occlusal Splint Materials Manufactured By Various Methods: A Systematic Review

Abstract

Purpose To systematically review studies on various materials and methods used for wear testing of occlusal devices and their antagonists in vitro and in vivo. Methods An electronic search in OVID, Web of Science, PubMed and Scopus was conducted using the following terms (MeSH words) with any synonyms and closed terms: “Splint*” OR “occlusal splint*” OR “night guard” OR “occlusal device” OR “occlusal devices” OR “deprogrammer” OR “bite splint” OR “bite plane” OR “orthotic appliance*” OR “orthotic devices” AND “wear” OR “two‐body wear” OR “three‐body wear” OR “tooth wear” OR “wear measurement*” OR “wear behaviour” OR “wear behavior” OR “abrasion” AND “Polymethyl Methacrylate” OR “PMMA” OR “acrylic resin*” OR “dental material*” OR “dental enamel” OR “CAD” OR “CAM” OR “PEEK” OR “material* testing”. Database search was limited to English‐language publications and published between 2001 and 1st of September 2021. A further hand search was done to ensure all materials were captured. Results After the removal of duplicates, 115 studies were identified, and 11 were chosen for review. Studies showed that the lowest volumetric loss was observed in PEEK occlusal device materials, whereas heat‐cure, CAD‐milled, and 3D printed occlusal device materials had no significant difference in wear. Vacuum‐formed materials showed the highest wear among all groups. Testing parameters were found to be inconsistent across all studies. Conclusion There is a need for standardization of in vitro and in vivo wear measurement and testing protocols as this study revealed a wide variety of testing protocols which potentially could influence the outcome. Polishing procedures are required for the material. Limited studies are available on 3D printed occlusal device materials and would therefore require further investigation, especially on printing build angles and settings. Further clinical studies would be advantageous to provide guidance on the selection of the best occlusal device material that would last the longest without remake.

Two-body wear of occlusal splint materials from subtractive computer-aided manufacturing and three-dimensional printing

“…However, there is no standardization in testing parameters like force, substrates geometry or cycle numbers among others. Additionally, the abrasion resistance of 3DP occlusal splints cannot yet be clearly classified against conventional and milled ones [ 23 ]. Forces used in two-body wear investigations vary between 5 and 50 N, with 50 N being used predominantly, which is considered the standard [ 24 ].…”

“…Forces used in two-body wear investigations vary between 5 and 50 N, with 50 N being used predominantly, which is considered the standard [ 24 ]. Besides cylindrical substrates with a flat surface, crown-shaped substrates were used in the investigations representing a more detailed replica of the clinical oral situation [ 23 , 24 ]. The number of chewing cycles varies according to the different wearing times of occlusal splints, in some cases from 10,000 to 60,000 and up to 200,000 cycles [ 23 ].…”

“…Besides cylindrical substrates with a flat surface, crown-shaped substrates were used in the investigations representing a more detailed replica of the clinical oral situation [ 23 , 24 ]. The number of chewing cycles varies according to the different wearing times of occlusal splints, in some cases from 10,000 to 60,000 and up to 200,000 cycles [ 23 ]. It should be noted that a higher number of chewing cycles allows for a better differentiation of the values due to the increased abrasion values [ 24 , 25 ].…”

“…It should be noted that a higher number of chewing cycles allows for a better differentiation of the values due to the increased abrasion values [ 24 , 25 ]. Data on the comparison of 3DP occlusal splint materials with conventional and milled ones is very limited [ 23 , 24 , 26 , 27 ]. While one investigation reported the highest abrasion losses in printed occlusal splint materials compared to milled and casted products [ 24 ], others found no differences in wear resistance [ 26 , 27 ].…”

Accuracy of 3D-Printed Occlusal Devices of Different Volumes Using a Digital Light Processing Printer

“…To fabricate conventional occlusal devices, a physical cast is essential. Depending on the type of occlusal device, vacuum thermoforming, sprinkling, or injection molding are commonly used methods to produce occlusal devices from auto-, heat-, or light-polymerized acrylic materials [10][11][12][13][14][15]. To produce conventional therapeutic devices a technician needs to be involved and many time-consuming working steps are necessary.…”