Series 500

The specimens were stored in a dry environment for 24 h at 37 °C before being sectioned into 1 × 1 mm² cross-sectional bars with a slow-speed diamond machine (Model Isomet, Buehler, IL, USA). The specimens were measured with a digital vernier caliper (Mitutoyo series 500, Mitutoyo, Kawasaki, Japan), as shown in Figure 2.
The thermocycling group was divided based on different chemical agent treatments into five subgroups, just as for the non-thermocycling group.
The thermocycle specimens underwent 10,000-cycle thermocycling between water baths at 5 °C and 55 °C, with a dwell time of 60 s in each water bath.
Each specimen was attached to a metal grip, as shown in Figure 3, which was attached to a Universal Testing Machine (EZ-S 500N, Shimadzu Corporation, Kyoto, Japan) with cyanoacrylate glue (Model Repair ll, Sankin Industry, Tokyo, Japan). Tensile strength was then applied at a crosshead speed of 1 mm/min until failure occurred.
The microtensile bond strength was determined by the applied tension divided by the bonded area. However, because the post-composite core interface was curved, this area was measured using the following mathematical formula:
where r, L, and h are the diameter, width, and thickness of the post, respectively, as shown in Figure 4.

The specimens were stored in a dry environment for 24 h at 37 °C before being sectioned into 1 × 1 mm² cross-sectional bars with a slow-speed diamond machine (Model Isomet, Buehler, IL, USA). The specimens were measured with a digital vernier caliper (Mitutoyo series 500, Mitutoyo, Kawasaki, Japan), as shown in Figure 2.
The thermocycling group was divided based on different chemical agent treatments into five subgroups, just as for the non-thermocycling group.
The thermocycle specimens underwent 10,000-cycle thermocycling between water baths at 5 °C and 55 °C, with a dwell time of 60 s in each water bath.
Each specimen was attached to a metal grip, as shown in Figure 3, which was attached to a Universal Testing Machine (EZ-S 500N, Shimadzu Corporation, Kyoto, Japan) with cyanoacrylate glue (Model Repair ll, Sankin Industry, Tokyo, Japan). Tensile strength was then applied at a crosshead speed of 1 mm/min until failure occurred.
The microtensile bond strength was determined by the applied tension divided by the bonded area. However, because the post-composite core interface was curved, this area was measured using the following mathematical formula:
where r, L, and h are the diameter, width, and thickness of the post, respectively, as shown in Figure 4.

A digital sliding caliper (SuperCaliper SERIES 500, Mitutoyo, Thailand) was used to measure AGD to the nearest 0.1 mm. Newborns were placed in a supine position. An assistant held both hips in flexion, flexed and pulled the knees back towards the shoulders. The caliper was positioned adjacent to the surface of the genitalia, digital screen turned away from the researcher, and the single AGD measurement was obtained.
In males, AGD was measured from the center of the anus to the anterior base of the penis (anopenile distance, AGD_AP) and to the perineoscrotal junction (anoscrotal distance, AGD_AS). In females, AGD was measured from the center of the anus to the clitoris (anoclitoral distance, AGD_AC) and to the posterior fourchette (anofourchette distance, AGD_AF) (Fig. 1). The anogenital distance ratio (AGD ratio) is calculated as AGD_AS divided by AGD_AP in males and AGD_AF divided by AGD_AC in females.Fig. 1

Anogenital distance measurement. AP: distance from anus to anterior base of penis. AS: distance from anus to perineoscrotal junction. AC: distance from anus to clitoris. AF: distance from anus to posterior fourchette