Figure 1.
Modern lower premolars presenting non-carious cervical lesions (NCCLs).
Arrows point towards the NCCLs in the buccal cervical region of the lower left first and second premolar (LP1 and LP2, respectively).
Figure 2.
The maximum principal stress distribution for specimen S23 and S81 lower right second premolars (RP2).
A, specimen S23 in occlusal, buccal, lingual, mesial and distal view. B. specimen S81 in occlusal, buccal, lingual, mesial and distal view. Blue spots in the occlusal surface (compressive stress) represent the contact areas with the antagonistic teeth, during maximum intercuspation (see Video S1 for specimen S23, and Video S2 for specimen S81), where the load was applied. Red spots represent tensile stresses. B, buccal; D, distal; L, lingual; M, mesial.
Figure 3.
The maximum principal stress distribution for specimen S5 and S126 lower right second premolars (RP2).
A, specimen S5 in occlusal, buccal, lingual, mesial and distal view. B. specimen S126 in occlusal, buccal, lingual, mesial and distal view. Blue spots in the occlusal surface (compressive stress) represent the contact areas with the antagonistic teeth, during maximum intercuspation (see Video S3 for specimen S5, and Video S4 for specimen S126), where the load was applied. Red spots represent tensile stresses. B, buccal; D, distal; L, lingual; M, mesial.
Figure 4.
The maximum principal stress distribution for specimen S23w and S81w lower right second premolars (RP2).
A, specimen S23w in occlusal, buccal, lingual, mesial and distal view. B. specimen S81w in occlusal, buccal, lingual, mesial and distal view. Blue spots in the occlusal surface (compressive stress) represent the contact areas with the antagonistic teeth, during maximum intercuspation (see Video S5 for specimen S23w, and Video S6 for specimen S81w), where the load was applied. Red spots represent tensile stresses. B, buccal; D, distal; L, lingual; M, mesial.
Figure 5.
Differences in tensile stress values between the original (S23 and S81) and the artificially worn down (S23w and S81w) lower right second premolars.
A, the maximum principal stress values for specimen S23 and S23w based on 10 homologous nodes in the buccal cervical region. B, the maximum principal stress values for specimen S81 and S81w based on 10 homologous nodes in the buccal cervical region.
Figure 6.
Cast of specimen S81 in the dental articulator (PROTAR, KaVo Dental GmbH).
A, buccal view of the specimen during the artificial attrition experiment of the RP2 based on the individual pattern of occlusal movements. B, occlusal view of specimen S81w RP1-RM1 crowns with artificially enlarged wear facets.
Figure 7.
Collision detection for specimen S126 in the Occlusal Fingerprint Analyser (OFA) software.
A, mesiolingual view during maximum intercuspation between the lower right premolars and first molar (RP1-RM1) and the upper right premolars (RP1-RP2). B, the RP1-RP2 are transparent to better show the collision (red areas) on the occlusal surface of the RP2. See also Video S4. B = buccal; D = distal; L = lingual; M = mesial.
Figure 8.
Loading position and direction for specimen S23, S23w, S81, S81w, S5 and S126.
For each lower right second premolar (RP2) only the volumetric mesh of the enamel is displayed. The load (black arrows) was distributed proportionally according to the occlusal contact areas detected in the Occlusal Fingerprint Analyser (OFA) software. D = distal; L = lingual; M = mesial.
Table 1.
Elastic properties of dental and bone tissues.