Orthodontics and Orthodontology Commons^™

The Strategy For Uprighting A Deep Horizontally Impacted Mandibular Second Molar, Hui-Wen Cheng, Chia-Tze Kao, Chih-Chen Chou, Ching-Yi Tsai, Hsing-Yeh Shen, Wen Ken Tai

Taiwanese Journal of Orthodontics

An orthodontic treatment that involves uprighting of deep horizontally impacted mandibular second molars (MM2) can be a challenging procedure. This case report demonstrates an approach to correct an impacted MM2, specifically in a 21-year-old male patient who presented with a Class II division 2 malocclusion, deep bite, and bilateral maxillary second molars with buccal crossbite. Correction of the impacted MM2 had been achieved using a ramus temporary anchorage device (TAD), which applied pulling and extruding forces along with an uprighting moment. Addressing the deep bite required proclination of incisors, utilization of an intrusion arch for maxillary incisors, and implementation of …

Improved Superelastic Wire (Isw) Treatment For Skeletal Class Iii Malocclusion With Anterior Open Bite And Missing Upper Left Incisor, Chun-Yi Huang, Yung-Hui Chen, Szu-Ying Yu, Hui Tseng, Jian-Hong Yu

Taiwanese Journal of Orthodontics

This article reports the orthodontic treatment using improved superelastic Ti-Ni alloy wire for a non-surgical case of skeletal Class III combined with anterior open bite, posterior crossbite, and missing the tooth 21. The treatment processes included space re-opening for the tooth 21 to facilitate replacement with prosthesis, the application of Class III elastics combined with anterior retraction and active tie-back for space closure. Meanwhile, adjustment of bracket position and wire bending were used for detailing and finishing. Interdisciplinary teamwork with orthognathic surgery and prosthetic expertise enhanced rehabilitation of the tooth 21. After a 38-month treatment, the patient was very satisfied …

An Overview Of Patient Preference When Choosing A Dentist And Orthodontist, Chi Yuo Tee, Johnson Hsin-Chung Cheng, Daniel De-Shing Chen, Chi-Yang Tsai, Od Bayarsaikhan

Taiwanese Journal of Orthodontics

Purpose: The purpose of this study is to provide a better understanding to dentists and orthodontists about patient’s preferences when they are choosing their dentist.

Method: The articles from this study were identified in PubMed, ResearchGate, and ScienceDirect databases. Based on the obtained articles, we classify patient preferences into clinical settings, dentist and orthodontic factors, administration system, and the impact of using social media networks for dental treatment marketing. The inclusion criteria for this literature review includes the articles that related to the topic, published from 2008 till 2023, written in English from PubMed, ResearchGate, and ScienceDirect. The exclusion criteria …

Agenesis Of Mandibular Incisors And Orthodontic Management, S. Lalithapriya, N. Kurunji Kumaran

Taiwanese Journal of Orthodontics

Background: Patients with mandibular incisors agenesis often seek treatment to address both aesthetic and functional concerns. The clinical examination and management for these patients may differ from our standard diagnosis and treatment planning protocols.

Objective: This article aimed to collect and review relevant literatures, discussing the necessity for specific attention to the quantity and location of missing mandibular incisors.

Method and results: An electronic literature search was conducted in PubMed and the Cochrane Central Library, focusing on specific objectives. Relevant articles were identified, resulting in a total of 64 articles after duplicates and irrelevant sources were removed.

Discussion and conclusion: …

Load-Deflection Behaviors Of Superelastic Niti Wires Using Two Bending Test Methods Including Passive Self-Ligating Brackets, Hsiu-Ming Hsu, Kuan-Chung Chen, Chen-Jung Chang, Tzer-Min Lee, Jia-Kuang Liu

Taiwanese Journal of Orthodontics

Purpose: Most load-deflection curves of NiTi wires were obtained by three-point test methods, but only few comparative studies had been reported about load-deflection behaviors of superelastic NiTi wires using three-bracket bending test mothod. The purpose of this study was to compare load-deflection behavior of different superelastic NiTi wires using two different bending test including passive self-ligating brackets.

Materials and methods: The study comprised four groups of superelastic NiTi wires: 0.014-inch ThermoNiTi, 0.014-inch CuNiTi, 0.016 x 0.025-inch ThermoNiTi and 0.016 x 0.025-inch 27°C CuNiTi. Each group had 10 pieces of wires to be tested. Then, three-point bending test and three-bracket bending …

Cortical Bone Thickness For Potential Anchorage Placement In Unilateral Cleft Lip And Palate Patients, Supeepan Boonyarattanasoontorn, Prajak Jariyapongpaiboon

Taiwanese Journal of Orthodontics

Purpose: The aim of this study was to measure the cortical bone thickness of the infrazygomatic crest area in individuals with non-syndromic unilateral cleft lip and palate (UCLP) with maxillary expansion using cone-beam computed tomography (CBCT). Materials and Methods: CBCT scans were obtained from 12 Thai non-syndromic UCLP patients with an average age of 14 years. Five horizontal and 8 vertical reference planes were drawn at the infrazygomatic crest area, and the cortical bone thickness was measured at 40 intersection points on the cleft and non-cleft sides. Results: The mean cortical bone thickness of the 40 measured points was 1.25 …

Successful Orthodontic Treatment Of Bimaxillary Protrusion Case With An Ankylosed Incisor—A Case Report And Decision-Making Process, Shu-Cheng Lin, Szu-Ching Lee, Yi-Ching Ho, Kai-Hsiang Chuang, Tzu-Ying Wu

Taiwanese Journal of Orthodontics

The treatment of ankylosed incisor is challenging for orthodontists, necessitating accurate diagnosis, well-considered treatment planning, and close collaboration among interdisciplinary teams to achieve favorable esthetic and periodontal outcomes. For ankylosed cases, accurate diagnosis depends on detailed clinical examination and 3D radiographic images. This case report described the treatment of a bimaxillary protrusive female with an ankylosed maxillary left central incisor. The decision regarding treatment was based on the severity of dental ankylosis and replacement root resorption. Each treatment plan comes with its own set of advantages and disadvantages. In this case, the decoronation treatment plan and prosthesis was implemented, resulting …

Orthodontic And Surgical Treatment Of A Patient With Cleidocranial Dysplasia Syndrome: Introducing A New Appliance For Traction Of Multiple Impacted Teeth, Sanaz Soheilifar, Sepideh Soheilifar, Sara Soheilifar, Navid Naghdi

Taiwanese Journal of Orthodontics

Cleidocranial Dysplasia (CCD) is a syndrome that causes skeletal growth disturbances. The impaction of many permanent teeth and several supernumerary teeth are among the dental problems of patients with this syndrome. This patient was a 14 y/o girl with CCD syndrome. She was skeletal Cl III with reverse overjet; many impacted teeth, and several supernumerary teeth. Orthodontic treatment was done in two stages. In the first stage, supernumerary anterior teeth were extracted, and the impacted teeth were exposed for traction. In the second stage, posterior supernumerary teeth were removed, and upper canines and posterior impacted teeth were exposed for forced …

A Coronectomy And Orthodontic Protraction Of An Impacted Lower Third Molar Compressed To The Inferior Alveolar Nerve: A Case Report, Johnson Hsin-Chung Cheng, Daniel De-Shing Chen, Bou-Yue Peng, Pei-Hsuan Chen

Taiwanese Journal of Orthodontics

Background: Neurological damage may occur during a third molar extraction procedure when the tooth root is near the mandibular canal. Although the incidence of this complication is low, a great range of variability has been reported in the literature. Several methods to reduce or eliminate this complication have been proposed, such as orthodontic-assisted extraction, extraction of the second molar, or an intentional odontectomy. Objective: The objective of this case report is to present a low risk extraction procedure: a coronectomy with forced eruption (COFE) to avoid potential neural damage when removal of lower wisdom tooth compressing inferior alveolar nerve in …

Non-Extraction Orthodontics In Severe Open Bite With Disc Plication Surgery Of The Temporomandibular Joint, Jessica Chia-Yi Wang, Meng-Yen Chen, Kuan-Yu Lin, Tung-Yiu Wong, Chen-Jung Chang

Taiwanese Journal of Orthodontics

Open bite malocclusion is among the most challenging orthodontic deformities to correct. Among the etiological factors of anterior open-bite, degenerative change in temporomandibular joints (TMJs) is the most difficult condition to manage. The most appropriate treatment modality for TMJ disorder with disc displacement remains controversal. Disc repositioning surgery is a treatment option when conservative treatment has failed to resolve symptoms. We presented a patient had history of gradual bite opening associated with joint stiffness and clicking. She received occlusal splint therapy for more than 10 years, and the occlusion was stable for 1 year before orthodontic treatment was initiated. Based …

Correlation Of Symphyseal Angle And Various Skeletal Patterns In Skeletal Class I Malocclusion, Dipankar Shrestha, Jyoti Dhakal, Rabindra Man Shrestha, Asal Acharya, Utsav Gautam

Taiwanese Journal of Orthodontics

Introduction: Skeletal growth pattern is an important parameter used in orthodontics for diagnosis and treatment planning. Lateral cephalogram is commonly used to evaluate skeletal growth pattern. Orthopantamogram (OPG) can also be used to evaluate skeletal growth pattern with parameters like gonial angle and symphyseal angle (SA). This study deals with symphyseal angle and its correlation with skeletal growth patterns. Objective: To correlate symphyseal angle with different skeletal growth patterns in skeletal Class I sample. Materials and Methods: The study was a cross-sectional, observational study including 60 patients of age 15 - 49 years with skeletal Class I pattern selected from …

Improved Super-Elastic Ti-Ni Alloy Wire (Isw) For Treatment Of Adult Angle Class Iii With Anterior Crossbite, Pin-Yu Chen, Yuan-Hou Chen, I-Jia Wang, Jian-Hong Yu

Taiwanese Journal of Orthodontics

An adult female (35 years old) came for orthodontic consultation with a chief complaint of poor dental alignment with protruded mandible. Clinical findings revealed that Class III malocclusion with functional anterior crossbite. Low Hysteresis Improved Super-elastic TieNi alloy wire (ISW), developed by Tokyo Medical and Dental University with ISW curve applied over upper arch for flaring out the upper anterior tooth. MEAW technique applied on lower arch to correct a negative overjet. Treatment was completed within 41 months and patient was pleased with the improvement of appearance and dental alignment.

Substitution Of Maxillary Central Incisor With Forced Eruption Of Impacted Maxillary Canine, Wei-Lun Lim, Huei-Mei Tsai, Yu-Ling Cheng, Yuen-Yung Tsang, Ming-Jeaun Su, Chia-Yi Pan

Taiwanese Journal of Orthodontics

This case report describes the orthodontic management of missing teeth and rehabilitation needs in a 26-year-old woman. Several missing teeth on her maxillary anterior esthetic zone, a poor prognosed left mandibular first molar and a missing right mandibular first molar was also found. The treatment plan included extraction of the unrestorable maxillary left incisor, surgical exposure and forced eruption of the impacted maxillary left canine. While on the lower arch, protraction of mandibular second and third molars was planned. A good functional occlusion was achieved after 42 months treatment duration. The transposed impacted maxillary left canine was orthodontically extruded and …

Distribution Of Different Skeletal And Dental Relations Among Orthodontic Patients In Recent 5 Years: A Retrospective Study, Zong-Zhe Tsai, Morton Chang, Yu-Chuan Tseng

Taiwanese Journal of Orthodontics

The prevalence of malocclusion differs significantly from race to race. The cause of malocclusion could be multifactorial. Previous studies have demonstrated quantitative information on skeletal and dental relations in different countries. This study focuses on patients who had received orthodontic data collection and analysis in a specific medical center. Skeletal relation and Angle’s dental classification of male and female were statisticized and analyzed. Skeletal relation of Class I was 45.4%, Class II was 29.5%, and Class III was 25.1%. Angle’s dental classification of Class I was 39.3%; Class II was 30.8%; Class III was 29.9%. There was a statistically significant …

Comparison Of Lateral Cephalometry And Cone-Beam Computed Tomography Techniques For Measuring Alveolar Bone Thickness Around Maxillary Incisors, Farzaneh Ahrari, Mostafa Shahabi, Hossein Hosseini-Zarch, Mohammad Javad Alavi

Taiwanese Journal of Orthodontics

Purpose: It is valuable to detect whether bone thickness measurements performed on lateral cephalograms reflect the values obtained from three-dimensional images. The present study compared lateral cephalometry and cone-beam computed tomography (CBCT) for evaluating alveolar bone thickness surrounding maxillary central incisors.

Methods: The study included the records of 55 patients who had both lateral cephalograms and CBCT scans of the maxilla. In cephalograms, the alveolar bone thickness was measured at the crestal, middle, and apical levels of maxillary incisors at the buccal and lingual sides. Bone thickness was also measured at the corresponding points on CBCT images, and the data …

Facial Growth: Does It Play A Role In Long-Term Stability Of Orthodontic Treatment?, Ib Leth Nielsen

Taiwanese Journal of Orthodontics

Following orthodontic treatment there is usually a period of retention to maintain the treatment result. This period can vary from a few years to even lifelong retention all depending upon the clinician, type of treatment and severity of the initial malocclusion. In most cases retention is planned for one to two years, but some clinicians routinely recommend continuous retention into adulthood. The retention planned for a patient is unfortunately often based on intuition rather than on scientific evidence. Furthermore, the retention is frequently not planned based on the initial malocclusion, the patient's facial growth pattern nor is attention paid to …

Improved Super-Elastic Ti-Ni Alloy Wire For The Treatment Of Skeletal Class Iii With Unilateral Buccally Positioned High Canine, Yi-Mien Cheng, Chih-Chieh Lin, Yu-Cheng Lo, Yuan-Hou Chen, Jian-Hong Yu

Taiwanese Journal of Orthodontics

A 20-year-old male adult came to the clinic with a chief complaint of poor dental alignment. Clinical examination had revealed Skeletal Class III with an upper right buccally positioned high canine, anterior crowding, midline deviation and both maxillary lateral incisors crossbite. Four bimaxillary premolars were extracted. Improved super-elastic Ti-Ni alloy wire (ISW, developed by Tokyo Medical and Dental University) leveling was performed to relieve the crowding and to correct the high canine and midline deviation. Intermaxillary elastics (IME) was applied for a better interdigitation. Treatment was completed within 29 months and a desirable occlusion was achieved.

Clear Aligner Treatment In An Adolescent Female With Hyperdivergent Growth Pattern Of The Mandible, Chih-Jan Chen, Yu-Ling Cheng, Yuen-Yung Tsang, Huei-Mei Tsai, Yi-Min Liu

Taiwanese Journal of Orthodontics

This study investigated the application of a clear aligner system in treatment of an adolescent Taiwanese female exhibiting a high mandibular plane angle, with a particular emphasis on the alignment of crowded upper anterior teeth. The treatment plan excluded tooth extraction and applied sequential distalization and transverse expansion across both dental arches instead. The alleviation of crowding and increased arch width was accomplished, while maintaining optimal vertical dimension control. The treatment yielded observable improvements in both oral function and aesthetic appearance

Bilateral Maxillary Canine Substitution With High Impaction In The Center Of Anterior Palate, Chien-Man Chang, Ying-Chen Chen, Ellen Wen-Ching Ko

Taiwanese Journal of Orthodontics

This case report described the treatment of a 16 y/o female who was referred for her bilateral maxillary impacted canines. Her chief complaint also involved lower crooked front teeth. She presented with skeletal Class I with orthodivergent facial pattern and dental Class II relationship. Clinical oral examination revealed two peg lateral incisors and two retained primary canines in the upper arch. The panoramic film showed two maxillary impacted canines near the center of palate. Before the orthodontic intervention, surgical exposure was conducted with open window technique. A transpalatal arch with 2 soldered hooks was inserted as anchorage for distal traction …

Surgical-Orthodontic Correction Of Skeletal Class Iii Anterior Open Bite With Facial Asymmetry, Hao-Hsiang Chang, Cheng-Hui Lin, Ellen Wen-Ching Ko

Taiwanese Journal of Orthodontics

Class III anterior open bite (AOB) is characterized by mandibular downward movement with anteroposterior discrepancy and long face deformity. This often leads to esthetic and functional problem that decrease the Quality of Life in patients. Treatment decision of AOB is always challenging whether goes for camouflage therapy or orthognathic surgery. A 26-year-old female suffered from anterior open bite and facial asymmetry. The clinical and radiographic examination revealed skeletal Class III relationship with hyperdivergent facial type, facial asymmetry with chin deviation to right, and AOB of -5 mm overbite. The pre-surgical orthodontic treatment included partial anterior retraction of upper anterior teeth …

Orthodontic Retreatment Of Class Ii Division 2 Malocclusion With Deep Bite And Gummy Smile Using Miniscrews, Hsin-Yi Lo, Hung-Jen Wang, Yu-Lian Lin

Taiwanese Journal of Orthodontics

Orthodontic treatment of Class II Division 2 malocclusion with gummy smile and deep bite is a challenge under the circumstances of lacking skeletal anchorage device. In this case report, we illustrated a miniscrew-assisted orthodontic retreatment of a 29-year-old female patient, who came to our department with a chief complaint of her unpleasant smile. The patient had previously undergone orthodontic treatment with 4-bicuspid extractions to correct her protrusive incisors. The clinical examination revealed a Class II division 2 malocclusion, 100% overbite, and a gummy smile. The philosophy of the orthodontic retreatment in this case was to correct Class II molar relationship …

Improved Super-Elastic Ti-Ni Alloy Wire For Nonsurgical Treatment Of Skeletal Class Iii Malocclusion Combined With Anterior Crowding And Anterior Crossbite Case, Po-Jui Lin, Yuan-Hou Chen, Ming-Ke Tsai, Chang-Chiang Yu, Jian-Hong Yu

Taiwanese Journal of Orthodontics

The article reported the use of improved super-elastic Ti-Ni alloy wire (ISW), which was developed by Tokyo Medical and Dental University, to correct a case of skeletal Class III malocclusion combined with anterior crowding and anterior crossbite. An 18-year-old male with a chief complaint of poor dental alignment and protruded lower incisors showed up in our clinic for treatment. Clinical examination revealed skeletal Class III facial profile. Anterior crowding and anterior crossbite could be also noted. Because the patient refused orthognathic surgery, we tried camouflage orthodontic treatment. First, we used ISW crossbite arch to eliminate the anterior interference in order …

Surgical-Orthodontic Treatment Of Class Iii Malocclusion With Anterior Open Bite, I-Ting Chiang, Cheng-Yu Wang, Yi-Jan Hsia, Chien-Cheng Chen, Yi-Horng Chen

Taiwanese Journal of Orthodontics

A 21-year-old female came with chief complaints of inability to incise food and poor esthetics. The patient presented with a concave facial profile, long face with a steep mandibular angle, incompetent lip closure, and acute nasolabial angle. Intraorally, she had negative 6 mm overjet, 3 mm open bite and dental crowding. She was diagnosed as severe skeletal Class III malocclusion and anterior open bite. The treatment plan included orthodontic treatment with orthognathic surgery and extraction of maxillary second molars, which were supra-erupted and tipped buccally. The pre-operative orthodontic alignment took 11 months. The surgical correction included maxillary Le Fort I …

Treatment Of Class Iii Malocclusion With Facial Asymmetry And Impacted Second Molar: A Case Report, Wei-Yu Chen, Chen-Jung Chang, Jen-Bang Lo, Pei-Ju Wu, Tung-Yiu Wong

Taiwanese Journal of Orthodontics

Symmetry is an important factor affecting facial attractiveness. The majority of subjects with facial asymmetry also exhibit Class III (CIII) malocclusion. However, the method used for three-dimensional analysis of facial asymmetry remains controversial. The optimal symmetry plane (OSP) method was developed to eliminate the identification errors that occur when using traditional orthodontic landmarks. Orthodontic treatment can become complicated in the presence of mandibular second molar impaction. Several parameters should be taken into consideration during the treatment planning, such as position of impacted tooth relative to anatomical structures and adjacent tooth and preexisting conditions in the impacted teeth. In this report, …

Treatment Strategy Of Mandibular Second Molar Impaction: A Literature Review, Heng-Tzu Shen, Johnson Hsin-Chung Cheng, Daniel De-Shing Chen

Taiwanese Journal of Orthodontics

Purpose: This literature review aimed to investigate the treatment consideration and strategy of mandibular second molar (MM2) comprehensively, which can be of great assistance on managing and solving such a rare disturbance. Methods: Previous studies were identified in PubMed or Embase database using the keywords “orthodontic,” “molar impaction,” and “uprighting molar.” To enrich the contents of every aspect of the topic, other several related articles were also reviewed and included. Results: Forty-six articles were included and systematically discussed in this review, which were arranged according to prevalence, etiology, diagnosis, treatment strategy, and clinical methods. The incidence of MM2 impaction is …

Transverse Malocclusions: Etiology, Development, Diagnosis And Treatment, Ib Leth Nielsen

Taiwanese Journal of Orthodontics

Malocclusions that involve the transverse dimension are very common in the orthodontic office. They can be as simple as a crossbite of the posterior teeth or as severe as a Class III malocclusion with a mandibular asymmetry. Transverse malocclusions can vary from being a simple dento-alveolar problem to a more complex challenge as represented by a skeletal asymmetry that has developed after puberty and causing temporomandibular disorder (TMD) problems. In this review we shall address the most common types of transverse malocclusions and review their etiology and development. The most typical etiology of transverse anomalies will be discussed, and we …

Multidisciplinary Retreatment Of Skeletal Class Ii Malocclusion With Obstructive Sleep Apnea And Multiple Prosthesis, Si-Rong Chen, Cheng-Hui Lin, Ellen Wen-Ching Ko

Taiwanese Journal of Orthodontics

Obstructive sleep apnea (OSA) is a common sleep disorder syndrome, especially in the middle-aged, obese men population. Patients suffer from an interrupted sleep at night, which could be life-threatening. Treatment alternatives include continuous positive airway pressure, mandible advanced device, nasal surgery and maxillo-mandibular advancement surgery. This article presented a patient who came with chief complaints of lower jaw retrusion, poor sleep quality, unsatisfactory occlusion and old prosthesis. The patient had declined the surgical-orthodontics in 12 years ago, and went for another camouflage orthodontic treatment with extraction of teeth and multiple prosthesis. He presented with skeletal Class II with retrognathic mandible …

Camouflage Treatment Of Skeletal Anterior Open Bite With Tongue Training, Cheng-Han Sie, Wen-Ken Tai, Chih-Chen Chou, Po-Yu Yang, Jung-Chun Yeh, Chun-Te Ho, Chia-Tze Kao

Taiwanese Journal of Orthodontics

The aim of this case report was to present an adult patient who suffered from poor occlusal function and poor aesthetic appearance due to skeletal anterior open bite. After orthodontic treatment, she was satisfied with improvements of mastication and esthetics. A case of 20-year-old female with skeletal Class II jaw relationship, mandible retrognathism and anterior open bite without signs and symptoms of temporomandibular disorder. Intraoral examination showed premature contact over bilateral posterior teeth and the forward resting position of tongue. Our treatment plan was orthodontic camouflage with extraction of all first premolars and tongue training. As forward resting position of …

Quality Of Life Changes In Taiwanese Patients With Dentofacial Deformities Undergoing Orthognathic Surgery, Jing Hao Ng, I-Chen Lee, Becky Chiang-Lin Liu, Ellen Wen-Ching Ko

Taiwanese Journal of Orthodontics

Objectives: The evaluation of orthognathic surgery (OgS) is shifting towards a coherent approach for patient care that balances objective clinician-defined measures with patient-centred outcome assessments, including health-related quality of life (QoL). This aim of this study adds to the pool of literature in East Asian subjects by studying the longitudinal QoL changes in Taiwanese patients with dentofacial deformities (DFD) undergoing OgS, using two standardized questionnaires at three different treatment stages. Materials and Methods: This prospective cohort study comprised 113 consecutive Taiwanese OgS patients who underwent surgical-orthodontic treatment between 2015 and 2018. The subjects completed SF-36 and OHIP-14 standardized questionnaires with …

Comparison Of Bone Thickness In Infrazygomatic Crest Area At Various Miniscrew Insertion Angles: A Cone-Beam Computed Tomographic Study, Rajju Dangal, Rabindra Man Shrestha, Jyoti Dhakal, Sujita Shrestha, Alka Gupta, Shreya Shah

Taiwanese Journal of Orthodontics

Introduction: The infrazygomatic crest (IZC) is an alternative site for miniscrew anchorage. It is important to analyze the anatomy of the region during preoperative planning to minimize the risk of unwanted tooth movement and injury to the vital structures. The literatures on the clinical application of miniscrew in IZC is scarce. Objective: To determine bone thickness, height and angle of insertion of miniscrew in the IZC region. Materials and methods: This cross-sectional observational comparative study included 44 patients above18 years. IZC bone thickness and height of miniscrew insertion were measured on cone-beam computed tomographic (CBCT) records. Student t-test was done …