StaTips Part IV: Selection, interpretation and reporting of the intraclass correlation coefficient

The intraclass correlation coefficient (ICC) is an index or repeatability that reflects both the degree of correlation and agreement between measurements. The ICC is widely used in orthodontic research for any continuous data set that satisfies assumptions for using the parametric methods. However, the ICC comprises a total of ten different variants not always recognized by researchers, which may give different outcomes. Here, a practical guide to choose the corrected variant of the ICC based on study design, and three different aspects (referred to as ‘model’, ‘type’ and ‘definition’) is provided. Finally, a full example of correct data interpretation and reporting is included

Gingival crevicular fluid alkaline phosphatase activity in relation to pubertal growth spurt and dental maturation: A multiple regression study

Introduction: The identification of the onset of the pubertal growth spurt has major clinical implications when dealing with orthodontic treatment in growing subjects. Aim: Through multivariate methods, this study evaluated possible relationships between the gingival crevicular fluid (GCF) alkaline phosphatase (ALP) activity and pubertal growth spurt and dentition phase. Materials and methods: One hundred healthy growing subjects (62 females, 38 males; mean age, 11.5±2.4 years) were enrolled into this doubleblind, prospective, cross-sectional-design study. Phases of skeletal maturation (pre - pubertal, pubertal, post - pubertal) was assessed using the cervical vertebral maturation method. Samples of GCF for the ALP activity determination were collected at the mesial and distal sites of the mandibular central incisors. The phases of the dentition were recorded as intermediate mixed, late mixed, or permanent. A multinomial multiple logistic regression model was used to assess relationships of the enzymatic activity to growth phases and dentition phases. Results: The GCF ALP activity was greater in the pubertal growth phase as compared to the pre - pubertal and post - pubertal growth phases. Significant adjusted odds ratios for the GCF ALP activity for the pre - pubertal and post - pubertal subjects, in relation to the pubertal group, were 0.76 and 0.84, respectively. No significant correlations were seen for the dentition phase. Conclusions: The GCF ALP activity is a valid candidate as a non - invasive biomarker for the identification of the pubertal growth spurt irrespective of the dentition phase

Radiographic growth indicators: The issue of diagnostic reliability and clinical feasibility

The use of radiographic growth indicators, such as the hand-and-wrist maturation (HWM) and cervical vertebral maturation (CVM)methods, has been recommended in previous clinical trials on the skeletal effects obtained by functional treatment in growing ClassII patients. The concept behind the use of indicators resides in the identification of the pubertal growth spurt in individual patients allowing the delivery of the treatment at this specific stage of skeletal maturation when the mandible response is expected to be maximum growth. Interestingly, while many of the former types of investigations reported a poor correlation between the stages of growth indicators (mainly the CVM) and mandibular growth spurt, most of the latter type of investigations reported clinically relevant favorable effects when the growth indicators are used. It is perhaps that investigations are still missing the relevant piece of evidence.The first critical issue relates to the correlation between two variables (i.e., stages of maturation and mandibular growth) that does not imply diagnostic accuracy, as it has been extensively reported for the case of dental maturation. The other relevant issue relates to the clinical feasibility of the repetition of the recording when dealing with invasive methods based on X-rays, irrespective of whether the methods are accurate. Meanwhile, more opportunity will be given by the use of non-invasive (serum or GCF) biomarkers. According to all these considerations, more reports will be necessary to elucidate the role of the growth indicators in orthodontics fully

StaTips Part V: The adjustment of the P value in the context of multiple comparisons

Very often researchers face the problem of multiple comparisons using the same data sets. When performing multiple comparisons, it happens that some P values below the desired cut-off level will be retrieved by chance, thus leading the researcher to have false positives. To reduce the risk of making wrong conclusions, statistical adjustment of the P values in the context of multiple comparisons has been proposed over the last decades. This article will deal with two simple procedures, Bonferroni and Holm, commonly used in dental literature to adjust the P values in case of multiple comparisons

Treatment effects of fixed functional appliances alone or in combination with multibracket appliances: A systematic review and meta-analysis

"Abstract Objective: To assess skeletal and dentoalveolar effects of fixed functional appliances, alone or in combination with multibracket appliances (comprehensive treatment), on Class II malocclusion in pubertal and postpubertal patients. Materials and Methods: Literature survey was conducted using the Medline, SCOPUS, LILACS, and SciELO databases and The Cochrane Library, and through a manual search. The studies retrieved had to have a matched untreated control group. No restrictions were set regarding the type of fixed appliance, treatment length, or to the cephalometric analysis used. Data extraction was mostly predefined at the protocol stage by two authors. Supplementary mandibular elongation was used for the meta-analysis. Results: Twelve articles qualified for the final analysis of which eight articles were on pubertal patients and four were on postpubertal patients. Overall supplementary total mandibular longationsas mean (95 confidence interval) were 1.95 mm (1.47 to 2.44) and 2.22 mm (1.63to 2.82) among pubertal patients and -1.73 mm (-2.60 to -0.86) and 0.44 mm (-0.78 to 1.66) among postpubertal patients, for the functional and comprehensive treatments, respectively. For pubertal subjects, maxillary growth restraint was also reported. Nevertheless, skeletal effects alone would not account for the whole Class II correction even in pubertal subjects with dentoalveolar effects always present. Conclusions: Fixed functional treatment is effective in treating Class II malocclusion with skeletal effects when performed during the pubertal growth phase, very few data are available on postpubertal patients.

Gingival crevicular fluid protein content and alkaline phosphatase activity in relation to pubertal growth phase

OBJECTIVE: To evaluate gingival crevicular fluid (GCF) protein content and alkaline phosphatase (ALP) activity in growing subjects in relation to stages of skeletal maturation, ie, the growth phase, as prepubertal, pubertal, and postpubertal. SUBJECTS AND METHODS: Fifty healthy growing subjects (31 girls and 19 boys; age range, 7.8–17.7 years) were enrolled in this study that followed a double-blind, prospective, cross-sectional design. Collection of GCF was performed at the mesial and distal sites of both central incisors, for the maxilla and mandible. Growth phase was assessed through the cervical vertebral maturation method. GCF parameters were expressed as total protein content, total ALP activity, and normalized ALP activity. RESULTS: The total GCF protein content was similar between the different growth phases. On the contrary, the total ALP activity showed a peak for the pubertal growth phase. The normalized GCF ALP activity was only poorly associated with growth phase. No differences were seen between the maxillary and mandibular sites, or between the sexes, for any GCF parameter. CONCLUSIONS: The total GCF protein content is not sensitive to the growth phase. However, GCF ALP activity has potential as a diagnostic aid for identification of the pubertal growth phase in individual subjects when expressed as total, but not normalized, values

Outcome stability of orthopaedic treatment of skeletal Class III malocclusion: A study of prognostic agreement between three models

Introduction: Long-term stability of the treatment outcome of skeletal Class III malocclusion is always not achievable, thereforeseveral prediction models of stability of orthopaedic treatment of the Class III malocclusion have been proposed. Aim: This cross-sectional study was aimed at the evaluation of the prognostic agreement and association between three differentprediction models based on skeletal parameters recorded on lateral cephalograms. Materials and methods: A total of 75 subjects (34 females and 41 males, age range 7-11, mean age 9.1±1.2years) having skeletal ClassIII malocclusion were included in the study. Prediction models reported by Baccetti et al. 2004 (prediction model 1), Moon et al.2005 (prediction model 2) and Yoshida et al. 2006 (prediction model 3), were considered. Percentage agreement and unweighted kappa coefficient evaluated the agreement between the prediction models in terms of stable or unstable cases. Multiple regressions were run to evaluate the association between the absolute scores obtained from each of the prediction model (prediction scores). Results: Percentage agreement ranged from 77.3% (models 2 and 3) to 89.3%, (models 1 and 2) and corresponding unweighted kappa coefficients ranged from 0.099 (models 1 and 3) to 0.205 (models 2 and 3). The prediction score from model 3 was significantly associated with those from both the other models; on the contrary, prediction scores from models 1 and 2 were not significantly associated. Conclusions: Agreement in terms of stability or instability outcome derived from these models is only partial and not satisfactory,even though significant association between the prediction scores denotes a common biological meaning of the models

Burden of herpes zoster-associated chronic pain in Italian patients aged 50 years and over (2009¿2010): a GP-based prospective cohort study.

BackgroundPost-herpetic neuralgia (PHN) is the most common complication in herpes zoster (HZ) patients.MethodsWe performed a longitudinal, prospective study in 108 general practices throughout Italy to assess how many immunocompetent patients aged ¿50 years with newly diagnosed HZ develop HZ-associated pain, its duration and management over 6-months. HZ-associated pain was assessed by a direct question to the patient and by self-assessment of the worst pain felt in the previous two weeks on a visual analogue scale (VAS), a score ¿3 was taken as pain. PHN was defined as pain reported during the study period persisting for ¿3 months. Quality of life (QoL) was measured using the SF-12 questionnaire.ResultsAt enrolment, 370 of the 413 patients (89.6%) reported HZ-associated pain which was still present in 20.6% and 9.2% of patients after three and six months, respectively, despite many patients receiving recommended anti-viral therapy. The overall QoL scores were lower than those in healthy Italians of similar age; scores for patients with HZ-associated pain were lower. The presence of >50 vesicles and VAS score ¿3 at enrolment, and being male were significantly associated with PHN at three months.ConclusionsThese results suggest that HZ and PHN represent an important burden of disease in the elderly. There is a need for interventions that can prevent and reduce the burden of HZ to help improve the quality of life of the elderly. These data may be useful as baseline epidemiology data for the assessment of the impact of the VZV vaccine in Italy, after its implementation

Overlap Between Orofacial Pain and Vulvar Vestibulitis Syndrome

To explore the prevalence of Orofacial Pain (OFP) among patients with Vulvar Vestibulitis Syndrome (VVS) and to examine the relationship between signs and symptoms of OFP and clinical characteristics of women with VVS; we specifically sought to investigate differences in psychological characteristics and self-reported severity of painful intercourse