Behnaz Alafchi

• PhD in biostatistics
• Hamedan University of Medical Sciences

OBJECTIVES: With a gradual decline in maternal mortality in recent years in Iran, this study was conducted to identify the remaining risk factors for maternal death. METHODS: This 8-year nested case-control study was conducted in Hamadan Province, in the west of Iran, from April 2006 to March 2014. It included 185 women (37 cases and 148 controls)...

Background: Breast cancer (BC) is one of the most common malignancies in women. Early diagnosis of BC and metastasis among the patients based on an accurate system can increase survival of the patients to >86%. This study aimed to compare the performance of six machine learning techniques two traditional methods for the prediction of BC survival an...

Background: Breast cancer is the first non-cutaneous malignancy in women and the second cause of death due to cancer all over the world. There are situations where researchers are interested in dynamic prediction of survival of patients where traditional models might fail to achieve this goal. We aimed to use a dynamic prediction model in analyzing...

Background: This study was conducted to better understand the influence of prognostic factors and the trend of CD4 cell count on the risk of progression to acquired immunodeficiency syndrome (AIDS) and tuberculosis (TB) infection among patients with human immunodeficiency virus (HIV) in a developing country. Methods: The information of 1530 HIV-inf...

Curing of colorectal cancer (CRC) occurs at the time of resection but it is not immediately observable. If the cancer is not completely eliminated, the patient will not be cured of cancer and will experience recurrence as the tumor has regrown to a detectable size. The main propose of the present study was to assess the effects of different covaria...

Background Leukemia patients’ caregivers often face care burden and low quality of life. Continuous virtual counseling can help to management these problems. This study examines effects of virtual counseling on the care burden and quality of life of family caregivers for leukemia patients. Method The study employed a randomized controlled trial pr...

Objectives The study evaluated six commonly used thermoplastic materials for clear aligner therapy, focusing on their mechanical properties to identify suitable options for patient treatment. Materials and Methods Bioart 0.75, Erkodur_al 0.8, Monoflex 0.8, Duran 0.625, Duran 0.75, and CA Pro 0.75 were selected. The three-point-bending tests in a ra...

Joint modeling of longitudinal and survival data is increasingly used in biomedical studies. However, existing joint models are not applicable to model the longitudinal ordinal responses with non-ignorable missing values caused by the occurrence of events in a multi-state process. In this article, we introduce a joint model for longitudinal ordinal...

Objectives One of the most important factors that has influence on dental implants success rate is marginal bone loss. The purpose of this study is to investigate the effect of the implant’s vertical position and the soft tissue’s thickness on the rate of marginal bone loss of the dental implant. Materials and methods In this single-blind randomiz...

Objective: The two factors of self-esteem and emotional intelligence are psychological factors that affect the progress of nursing students and, naturally, the training of skilled and self-efficacious nurses. The present study was conducted with the aim of determining the relationship between self-esteem and emotional intelligence of nursing studen...

Denture cleansers are extensively utilized to inhibit the colonization of various Candida species. Currently, additive technology in denture fabrication has become more prevalent. This study aims to assess the impact of disinfectants on the surface roughness and color stability of distinct denture bases. Disc-shaped samples (N=66) were exposed to t...

Background and Aim: Leukemia patients are physically and mentally vulnerable. Considering that the spiritual health of these people is directly and indirectly affected in the process of follow-up and treatment of their disease, and they may face death anxiety due to the nature of the disease, the existence of basic research, comprehensive and in ac...

Background Knowledge about the anatomy and morphology of the root canal system is essential for successful surgical and non-surgical root canal treatments. However, precise assessment of the root morphology and anatomy is not often possible on two-dimensional radiographs. This study aimed to investigate the association of root morphology of mandibu...

Introduction: Recurrent event data, as a generalization of survival data, are frequently observed in various areas of medical research, including sequential hospitalizations in patients with schizophrenia. As experiencing multiple relapses during schizophrenia can have many implications, such as self-harm or harm to others, loss of education or emp...

Objectives: This study assessed the shear bond strength (SBS) of stainless steel (SS) orthodontic brackets to specimens fabricated from polymethyl methacrylate (PMMA) temporary restorative material by 3D-printing, computer-aided design/computer-aided manufacturing (CAD/CAM) technology, and the conventional technique, after surface treatment by san...

Background: This study compared the amount of residual cement at the margin of implant-supported crowns cemented using the polytetrafluoroethylene (PTFE) tape, replica technique, and conventional cementation technique. Methods: In this in vitro experimental study, a mandibular model underwent full-arch scanning. The right first molar tooth was elim...

Background: Hypertension and diabetes are common comorbidities in patients with COVID-19 and could be influencing the mortality of such patients. The present study aimed to evaluate the effects of hypertension alone and in comorbidity with diabetes on the death within 30 days among inpatients with COVID-19 in presence of well-known determinates of...

Background: Knowing the shape of the root and the root canal system is essential for the success of the surgical and non-surgical treatment of the root canal, however; it is difficult to judge root and root canal anatomy from two-dimensional radiographs . The aim of this study is to investigate correlation between root morphology of the mandibular...

Survival data with a multi-state structure are frequently observed in follow-up studies. An analytic approach based on a multi-state model (MSM) should be used in longitudinal health studies in which a patient experiences a sequence of clinical progression events. One main objective in the MSM framework is variable selection, where attempts are mad...

Objectives: Breast cancer (BC) is the most common cause of cancer death in Iranian women. Sometimes death from other causes precludes the event of interest and makes the analysis complicated. The purpose of this study was to identify important prognostic factors associated with survival duration among patients with BC using random survival forests...

Background Anatomical analysis of the sphenoid sinus is important because of its proximity to vital neurovascular structures. The aim of this study is investigating the anatomy of the SS and its surrounding structures in CBCT images. Methodology In this retrospective cross-sectional study, 201 cone-beam computed tomography (CBCT) radiographs were...

Background and aims: Different methods are available for making temporary restorations. The purpose of this study was to determine and compare the shear bond strength of orthodontic brackets on temporary crowns made by three different methods. Materials and methods: In this experimental study, disc form samples (N=54) were made in dimensions 8×1...

Objectives White spot lesions (WSLs) are a real problem in patients with fixed orthodontic appliances with inadequate hygiene and eating habits. This study aimed at evaluating the synergic effects of NovaMin in fluoride toothpaste on remineralization of WSLs in patients with fixed orthodontic appliances. Methods In the present double-blind, random...

Introduction The hallux valgus, a painful forefoot deformity, is defined as lateral deviation of the hallux, which is highly correlated with forefoot pronation. This study aimed to compare the effect of two types of foot orthoses, one with and one without a varus forefoot wedge, on self-reported outcomes of pain, function, and QOL (by FAOS question...

In longitudinal studies, clinicians usually collect longitudinal biomarkers’ measurements over time until an event such as recovery, disease relapse, or death occurs. Joint modeling approaches are increasingly used to study the association between one longitudinal and one survival outcome. However, in practice, a patient may experience multiple dis...

BACKGROUND Background: Considering the high prevalence of metabolic syndrome (MetS) and its importance in the development of cardiovascular disease. OBJECTIVE we aimed to predict important factors for the incidence of MetS using data mining models. METHODS Methods: This prospective study was conducted on 3048 adults (aged ≥20 years), who particip...

Background Metabolic syndrome (MetS), a major contributor to cardiovascular disease and diabetes, is considered to be among the most common public health problems worldwide. Objective We aimed to identify and rank the most important nutritional and nonnutritional factors contributing to the development of MetS using a data-mining method. Methods Th...

Objectives: This study aimed to assess the relationship of frontal sinus height and width with the cervical vertebral maturation (CVM) for assessment of skeletal maturity. Materials and Methods: This retrospective study evaluated lateral cephalograms of 132 patients between 8 to 21 years, including 66 males and 66 females. For each of the six stage...

Objective Pharyngeal airway, maxilla, mandible and nasal septum are maxillofacial structures with intimate relationship. The mutual effects of these structures would modify treatment plan and final results of surgical or orthodontic interventions. The objective of this study was to evaluate the association of nasal septum deviation and pharyngeal a...

Objective: To assess the prevalence of soft tissue calcifications and their panoramic radiographic characteristics. Material and Methods: This descriptive retrospective study evaluated 2027 panoramic radiographs. The type and location of calcifications and the age and gender of patients were evaluated by two radiologists. Data were analyzed via SP...

Background Curing of colorectal cancer (CRC) occurs at the time of resection, but it is not immediately observable. If the cancer is not completely eliminated, the patient will not be cured of cancer and will experience a recurrence as the tumor has regrown to a detectable size. The main proposes of the present study was to assess the effects of di...

Objective: Lung cancer is the most frequently diagnosed cancer and the most leading cause of death due to cancer worldwide. This study aimed to use censored quintile regression model to estimate the effect of potential risk factors on survival of lung cancer patients. Methods: In this study we used a dataset of a retrospective cohort study conducte...

Background: Class II malocclusion is one of the most common orthodontic problems that can be divided into class II division 1 and division 2. Considering the differences between the 2 malocclusions, the present study was designed to compare the dentoskeletal changes caused by growth modification treatment. Methods: This retrospective study included...

This study is conducted to better understand the prognostic factors influencing the disease progression in patients with human immunodeficiency virus (HIV). This study was assessed the information of 1857, HIV-infected patients who had a medical record in Behavioral Diseases Counseling Centers from April 2004 to March 2014. The Cox-Aalen model was...

Background: Bipolar disorder is a severe, chronic and disabling mental disorder. The purpose of this study was to forecast the number of hospitalized patients with bipolar disorder in Hamadan Province, the west of Iran. Methods: In this study the data set containing the number of hospitalized patients with bipolar disorder from January 2009 to Janu...

Background: Bipolar disorder (BD) is a major public health problem. In time series count data there may be over dispersion, and serial dependency. In such situation some models that can consider the dependency are needed. The purpose current research was to use Poisson hidden Markov model to forecast new monthly BD instances. Methods: In current st...

Mortality rates and deaths from HIV/AIDS report annually and information for forecasting is not complete. Therefore, we have to choose a suitable method to fit the situation. According to the characteristics of this data, small size and imperfect, for analysis, we selected grey model first order one variable, GM(1,1). Data is collected and download...