Present Status in Polymeric Mouthguards. A Future Area for Additive Manufacturing?

Abstract

Athletes from contact sports are more prone to orofacial injuries because of the exposure to possible shocks and collisions derived from physical proximity. The use of protector polymeric mouthguards proved to be useful in the prevention of the described injuries. There are different types of mouthguards with varying ranges of protection and prices, but they are all made from polymers and share the same propose: to absorb and dissipate the impact energy resulting from the shocks. As they are used inside the mouth, they should not impair breathing and speaking nor compromise the comfort of the athlete. However, the ideal mouthguard is yet to be created. The choice of the most appropriate polymeric material and the standard required properties have not yet been reported. Regardless of the numerous studies in this field, normalized control parameters for both material characterization and mouthguard fabrication are absent. This paper aims to present a review of the current types of available mouthguards and their properties/characteristics. Moreover, a detailed description of the most common polymers for the fabrication of mouthguards, together with the manufacturing techniques, are discussed.

Keywords: 3D printing; orofacial injuries; polymeric mouthguards; polymers; processing.

Figure 1

Clinical appearance of gingiva: (A) Attached gingiva above and interdental papilla below; (B) mucogingival line separating attached gingival from mucosa; (C) free gingival margin; (D) posterior vestibular fornix; (E) anterior vestibular fornix or mucobuccal fold; (F) frenum area.

Figure 2

Maxillary and mandibular dental arches. The individual teeth can be numbered sequentially from mesial to distal in each quadrant (indicated in red) or uniquely numbered, starting with the right maxillary third molar as tooth number 1 (shown in black). The orientation of the teeth is indicated by labial, buccal, lingual, and palatal as reference. The relationship between teeth is indicated by mesial-distal terms [26]. Published by Elsevier.

Figure 3

Example of a dental stone model [31]. Published by Elsevier.

Figure 4

Basic design of a mouthguard: (A) edge of buccal flange; (B) edge of labial flange; (C) labial flange; (D) buccal flange; (E) occlusal surface; (F) edge of palatal flange; and (G) palatal flange [38]. Published by Elsevier.

Figure 5

Stock type mouthguard [41].

Figure 6

A mouth-formed mouthguard (“boil and bite” mouthguard) [47].

Figure 7

A custom-made mouthguard for the upper jaw ex-situ (adapted) [48]. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

Figure 8

Synthesis scheme of the synthesis of ethylene vinyl acetate (EVA) copolymer [72].

Figure 9

Pressure machine and molding condition (condition MP). The sheet frame at the top of the post was lowered, and the sheet covered the model when it sagged by 15 mm. The rear side of the model was pushed to move the model forward 20 mm, and then, the sheet was formed [110]. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.

Figure 10

Typical vacuum forming machine (adapted) [54]. Copyright Wiley-VCH Verlag GmbH & Co. KGaA. Reproduced with permission.