Dentition phase and chronological age in relation to gingival crevicular fluid alkaline phosphatase activity in growing subjects.

OBJECTIVE: Identification of skeletal maturation phases is of primary importance in terms of individual responsiveness to nearly all dentofacial orthopaedic treatments. In this regard, dentition phase and chronological age are still widely used to define the timing of and responsiveness to orthodontic treatments. Recently, gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity has been shown to be a reliable biomarker of skeletal maturation in growing subjects. Here, for the first time, circumpubertal dentition phases and chronological age were evaluated for correlations with GCF ALP activity, as a biomarker of skeletal maturation. MATERIALS AND METHODS: Eighty-five healthy growing subjects (51 females, 34 males; mean age, 11.7\ub12.3 years) were enrolled into this double-blind, prospective, cross-sectional-design study. Samples of GCF were collected from each subject at the mesial and distal sites of both of the central incisors, at the maxillary and mandibular arches. Their dentition phases were recorded as intermediate mixed, late mixed, or permanent. GCF ALP enzymatic activity was determined spectrophotometrically. RESULTS: The dentition phases showed median GCF ALP activities from 42.0 to 67.5 mU/sample. Although these were slightly greater for the permanent dentition, no significant differences were seen. Also, the chronological age did not correlate significantly with GCF ALP activity, and no significant differences were seen between maxillary and mandibular sites in any of the comparisons. CONCLUSIONS: Assessment for treatment timing of dentofacial disharmonies in individual patients that require monitoring of their skeletal maturation phases should not rely on their circumpubertal dentition phase and chronological ag

Diagnostic performance of dental maturity for identification of skeletal maturation phase.

The objective of this study is to analyse the diagnostic performance of the circumpubertal dental maturation phases for the identification of individual-specific skeletal maturation phases. A total of 354 healthy subjects, 208 females and 146 males (mean age, 11.1 \ub1 2.4 years; range, 6.8-17.1 years), were enrolled in the study. Dental maturity was assessed through the calcification stages from panoramic radiographs of the mandibular canine, the first and second premolars, and the second molar. Determination of skeletal maturity was according to the cervical vertebra maturation (CVM) method on lateral cephalograms. Diagnostic performances were evaluated according to the dental maturation stages for each tooth for the identification of the CVM stages and growth phases (as pre-pubertal, pubertal, and post-pubertal) using positive likelihood ratios (LHRs). A positive LHR threshold of 10 or more was considered for satisfactory reliability of any dental maturation stage for the identification of any of the CVM stages or growth phases. The positive LHRs were generally less than 2.0, with a few exceptions. These four teeth showed positive LHRs greater than 10 only for the identification of the pre-pubertal growth phase, with values from 10.8 for the second molar (stage E) to 39.3 for the first premolar (stage E). Dental maturation assessment is only useful for diagnosis of the pre-pubertal growth phase, and thus, precise information in relation to the timing of the onset of the growth spurt is not provided by these indices

Surface corrosion and fracture resistance of two nickel-titanium-based archwires induced by fluoride, pH, and thermocycling. An in vitro comparative study.

The present comparative study aimed to evaluate the surface corrosion and fracture resistance of two commercially available nickel-titanium (NiTi)-based archwires, as induced by a combination of fluoride, pH, and thermocycling. One hundred and ten rectangular section NiTi-based archwires were used, 55 of each of the following: thermally activated Thermaloy\uae and super-elastic NeoSentalloy\uae 100 g. Each of these was divided into five equal subgroups. One of these five subgroups did not undergo any treatment and served as the control, while the other four were subjected to 30 days of incubation at 37\ub0C under fluoridated artificial saliva (FS) at 1500 ppm fluoride treatment alone (two subgroups) or combined with a session of thermocycling (FS + Th) treatment at the end of incubation (two subgroups). Within each of the Thermaloy\uae and NeoSentalloy\uae groups, the FS and FS + Th treatments were performed under two different pH conditions: 5.5 and 3.5 (each with one subgroup per treatment). Analysis of the surface topography and tensile properties by means of scanning electron microscopy (a single sample per subgroup), atomic force microscopy, and a universal testing machine for ultimate tensile strength were carried out once in each of the control subgroups or immediately after the treatments in the other subgroups for 10 of the archwires. Non-parametric tests were used in the data analysis. Significant effects in terms of surface corrosion, but not fracture resistance, were seen mainly for the Thermaloy\uae group at the lowest pH, with no effects of Th irrespective of the group or pH condition. Different NiTi-based archwires can have different corrosion resistance, even though the effects of surface corrosion and fracture resistance appear not to be significant in clinical situations, especially considering that thermocycling had no effect on these parameters