A comparison between a conventional optical method and image-analysis for measuring the unimpeded eruption rate of the rat mandibular incisor

Abstract

The impeded/unimpeded eruption rates of the rat incisor have been much studied. The most commonly used optical microscopic method, which has inherent weaknesses, was compared here with an image-analysis method to measure the eruption rate of the mandibular incisor. The study also evaluated the incisal edge as a reference point for the measurement of the unimpeded eruption rate, and the frequency of shortening the mandibular incisor. The image-analysis method was found to be a simple and reliable technique that could replace the optical method. There was no significant difference between the data from the two methods; their kappa coefficients were similar at the 0.99 level. It was concluded that shortening the incisor in the measurement of the unimpeded eruption rate should be done at least every 48 h, and that the incisal edge of the shortened incisor can be used as the reference point for that measurement.

Induction of ankylosis in the incisor for orthodontic tooth movement in rats

“…Clinically, no vertical movement was seen, as verified by the incisor eruption rate. The eruption rates in the Experimental and Control groups were 0 and 0.39 mm day −1 , respectively, which are similar to results in previous studies . It is possible that the formation of the root was interrupted because the dental papillae and the enamel organ were cut .…”

“…For most orthodontic movements, as in OTM studies in animals, it is important that movement happen without loss of stability of the anchoring unit . Concerned with these factors, Ren et al.…”

“…Under normal conditions, the rat incisors are continuously growing to compensate for the natural wear that occurs as a function of normal chewing . This phenomenon leads to incisal migration of the orthodontic device, primarily in studies involving follow‐up periods of more than 10 days.…”

“…In all animals, marks were made with a diamond drill (4141, KG Sorensen, Cotia, SP, Brazil) up to the level of the interdental papilla in both incisors. Measurements were made from the marks in the incisors up to the most cervical gingival end of the respective teeth, using calibrated graticules in microscope eyepieces . Measurements were taken at 0, 3, 5, 7, and 9 days after tissue repair to determine the eruption rate of the incisors (Fig.…”

The impact of hypoestrogenism and occlusal function on MMP1, MMP8 and MMP13 expression in the odontogenic region in rats

“…The occlusal hypofunction condition was simulated adjusting the incisal edge, at the level of the gingival papilla, in the lower right incisor (Lee et al, 2002). Consequently, the contra-lateral side presents a hyper occlusal function, and thus the occlusal hyperfunction condition was establishes in the lower left incisor.…”