Mastication

2013 ◽  
Author(s):  
Martin E. Atkinson
Keyword(s):  
Occlusal Plane ◽  
Dental Arch ◽  
Posterior Teeth ◽  
Maxillary Molars ◽  
Anterior Teeth ◽  
Occlusal Surfaces ◽  
Mandibular Teeth ◽  
Maxilla And Mandible ◽  
Dynamic Relationships ◽  
Muscles Of Mastication

Now you have an understanding of the anatomy of the maxilla and mandible, the TMJs, and jaw musculature, we can examine how these structures work together to produce the complex actions involved in the biting and chewing of food. Technically, incision is biting a piece from a larger chunk of food and mastication is the grinding down of that piece into smaller components and mixing them with saliva. Mastication is often used to cover both actions. Box 26.1 briefly compares the anatomy of the human dentition to that of other mammals. As well as knowledge of the TMJ, muscles of mastication, and other muscles used in jaw movements, it is necessary to appreciate some aspects of the static and dynamic relationships of the teeth to understand chewing movements. The first thing to notice is the bigger width of the upper dental arch compared to the lower arch, a condition known as anisognathy. In Figure 26.1A , you can see that the maxillary molars overhang the mandibular teeth by half a cusp width so the buccal cusps of the lower molars and premolars occlude between the buccal and palatal cusps of the maxillary teeth. Observe also that the long axis of the maxillary molars and premolars incline buccally while the corresponding axis of the mandibular teeth incline lingually; the occlusal plane of the posterior teeth is thus curved transversely as illustrated in Figure 26.1A . It would be possible to chew food simply by moving the teeth up and down without any side-to-side movement, but this would be inefficient and not make full use of the cusps on the occlusal surfaces of posterior teeth. However, we can only chew on one side at a time because of the anisognathy of the upper and lower teeth. Due to anisognathic jaw positions, the maxillary anterior teeth are also going to protrude in front of the mandibular anterior teeth. Figure 26.1B illustrates the normal relationships of the anterior teeth. The maxillary incisors overhang the mandibular incisors by about 2–3 mm in the horizontal plane; this is called the overjet. The upper incisors usually have a vertical overhang, the overbite, of about the same amount. As mentioned in Chapter 24 , the mouth at rest is closed by tonic contraction of the muscles of mastication and facial expression.

Evaluation of the curve of Spee, curve of Wilson and Monson’s sphere in Iranian adults: A preliminary three-dimensional study

2020 ◽  
Author(s):  
Mahdie Chavoshzadeh Natanzi ◽  
Maryam Azimi Zavaree ◽  
Mehran Torabi ◽  
Farnaz Taghavi-Damghani ◽  
Seyed Mohammad Reza Hakimaneh ◽  
...  
Keyword(s):  
Racial Differences ◽  
Three Dimensional ◽  
Spherical Model ◽  
Occlusal Plane ◽  
Dental Arch ◽  
3 Dimensional ◽  
Curve Of Spee ◽  
Occlusal Surfaces ◽  
The Mean ◽  
Mandibular Teeth

Purpose : One of the required information in rehabilitating the occlusal plane in dentistry is the radius of Monson’s sphere , which like other anatomical indices varies in different races. The purpose of this study was to determine the radius of the Monson’s  sphere in a group of  Iranian. Materials & Methods  : 45 Iranian subjects (19 males & 26 females ) aged from 18 to 25 were selected for this study . The x,y,z coordinates of cusp tips of all  mandibular teeth except for the third molars obtained  with a 3-dimensional digitizer , were used to  derive a spherical model  of the occlusal surfaces’ curvature . From the best interpolating sphere , the radii of the Monson’s sphere was computed . Results : Although all of the computed variables were greater in men , the occlusal curvature of mandibular arch was not influenced by gender . The mean radius of the Monson’s  sphere was 111.5 mm ( 121 mm in men and 104 mm in women which was closer to the classic value of 4 inch , confirming Monson’s observations ) . Conclusion  : The average radius of the Monson’s sphere in this study was greater than the classic 4 inch value proposed by Monson and this result may suggest racial differences in the normal dental arch form that is important in occlusal rehabilitation. Although more researches are necessary in future to improve treatment results.

scholarly journals Dual-section versus conventional archwire for en-masse retraction of anterior teeth with direct skeletal anchorage: a finite element analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ryo Hamanaka ◽  
Daniele Cantarella ◽  
Luca Lombardo ◽  
Lorena Karanxha ◽  
Massimo Del Fabbro ◽  
...  
Keyword(s):  
Finite Element ◽  
Tooth Movement ◽  
Occlusal Plane ◽  
Skeletal Anchorage ◽  
Element Analysis ◽  
Posterior Teeth ◽  
Posterior Portion ◽  
Anterior Teeth ◽  
Retraction Force ◽  
En Masse Retraction

Abstract Background The aim of this study is to compare the biomechanical effects of the conventional 0.019 × 0.025-in stainless steel archwire with the dual-section archwire when en-masse retraction is performed with sliding mechanics and skeletal anchorage. Methods Models of maxillary dentition equipped with the 0.019 × 0.025-in archwire and the dual-section archwire, whose anterior portion is 0.021 × 0.025-in and posterior portion is 0.018 × 0.025-in were constructed. Then, long-term tooth movement during en-masse retraction was simulated using the finite element method. Power arms of 8, 10, 12 and 14 mm length were employed to control anterior torque, and retraction forces of 2 N were applied with a direct skeletal anchorage. Results For achieving bodily movement of the incisors, power arms longer than 14 mm were required for the 0.019 × 0.025-in archwire, while between 8 and 10 mm for the dual-section archwire. The longer the power arms, the greater the counter-clockwise rotation of the occlusal plane was produced. Frictional resistance generated between the archwire and brackets and tubes on the posterior teeth was smaller than 5% of the retraction force of 2 N. Conclusions The use of dual-section archwire might bring some biomechanical advantages as it allows to apply retraction force at a considerable lower height, and with a reduced occlusal plane rotation, compared to the conventional archwire. Clinical studies are needed to confirm the present results.

scholarly journals Epidemiological, clinical and pathological aspects of an outbreak of periodontitis in sheep

2016 ◽  
Vol 36 (11) ◽  
pp. 1075-1080 ◽  
Author(s):  
Natália S. Silva ◽  
◽  
José A.S. Silveira ◽  
Danillo Henrique S. Lima ◽  
Henrique A. Bomjardim ◽  
...  
Keyword(s):  
Clinical Signs ◽  
Bone Destruction ◽  
Pennisetum Purpureum ◽  
Dental Arch ◽  
Histopathological Analysis ◽  
Panicum Maximum ◽  
Molar Teeth ◽  
Maxillary Premolars ◽  
Mandibular Teeth ◽  
Maxilla And Mandible

ABSTRACT: The objective of this study was to describe the epidemiological, clinical and pathological aspects of an outbreak of periodontitis in sheep that occurred on a rural property in Benevides, in the state of Pará, Brazil. The first clinical signs of this disease in the herd - visible nodular swollen mandible - were observed about one month after the sheep began grazing on a recently renovated Panicum maximum cv. Massai pasture; the animals were also supplemented with elephant grass (Pennisetum purpureum). From the 545 adult Santa Ines, Dorper, Texel and crossbred sheep, 20 (3.7%) showed facial bulging, particularly of the mandible. These 20 sheep, which were generally over 36 months of age, had low body condition scores as well as dull and ruffled coats; many of them had loose or missing pre, upper or lower molars, showed the formation of abscesses and fistulas, exhibited pain upon palpation and had difficulty chewing. In the same herd, the prevalence of periodontal lesions at the premolars and molar teeth was evaluated via post-mortem examination of 39 young and 17 adult sheep. In 51.3% (20/39) of adolescents and in 100% of adults, periodontal lesions were found at least at one tooth of the dental arch, with unilateral or bilateral periodontal lesions at the maxillary and mandibular teeth. Histopathological analysis of 13 sheep revealed pyogranulomatous inflammation. The second and third maxillary premolars were the teeth that were most affected in young animals, whereas the third pre-molar and the molars, of the maxilla and mandible, were most often affected in adults. These lesions led to severe bone destruction, alterations in the dental arch, occlusion, tooth loss and periodontal abscesses. The epidemiological and clinic-pathological characteristics of this periodontitis outbreak, described here for the first time in sheep in Brazil, were similar to those for bovine periodontitis (“cara inchada”).

scholarly journals A Composite Laminate Veneer Technique for Diastema Closure: A Report of Ten Cases

2012 ◽  
Vol 2 (3) ◽  
pp. 67
Author(s):  
Emrullah Bahşi ◽  
Michele Callea ◽  
Bayram İnce ◽  
Marco Montanari ◽  
Mehmet Dallı ◽  
...  
Keyword(s):  
Composite Laminate ◽  
Native Speakers ◽  
Low Cost ◽  
Non Invasive ◽  
Anterior Teeth ◽  
Adhesive Dentistry ◽  
Cost Treatment ◽  
Native Speakers Of English ◽  
Mandibular Teeth ◽  
Maxilla And Mandible

Aim: Diastemas can be treated using periodontal, surgical, orthodontic, or prosthetic procedures. Composite laminate veneers can be applied to reduce or eliminate diastemas and represent a good aesthetic non-invasive alternative for these patients. This study presents the treatment results of 10 patients with diastemas between the anterior teeth of the maxilla and mandible with composite veneers. Methodology: Ten patients with diastemas between the anterior maxillary and mandibular teeth complaining of esthetic problems were treated at the Department of Operative Dentistry, University of Dicle. The periodontal health of the patients was acceptable and no caries were detected. Patients were informed of the treatment choices and composite resin veneers were selected as the better approach for each case. The presence of a diastema causes esthetic problems, especially in adolescents. Prosthetic and conservative methods are usually used to treat diastemas because these approaches are minimally invasive. The direct laminate technique has the advantages of low cost, treatment reversibility, and easy repair of the restoration intraorally. The direct composite laminate technique has become more effective because of improvements in adhesive dentistry. Conclusion: This study describes a direct composite laminate technique for the restoration of the anterior teeth of 10 patients with diastemas. These restorations were conservative and provide an inexpensive, one-visit aesthetic treatment for anterior teeth.  How to cite this article: Bahşi E, Callea M, İnce B, Montanari M, Dallı M, Batteli F, Akdoğan M, Gabriella C, Toptancı İR, Gabriela P, Yavuz İ. A Composite Laminate Veneer Technique for Diastema Closure: A Report of Ten Cases. Int Dent Res 2012;2:67-74. Linguistic Revision: The English in this manuscript has been checked by at least two professional editors, both native speakers of English.

scholarly journals The The effect of different solutions and thermocycling on the vickers hardness of acrylic resin denture teeth

2018 ◽  
Vol 8 (3) ◽  
pp. 117-122
Author(s):  
Hatice Özdemir ◽  
Zeynep Yeşil Duymuş
Keyword(s):  
Thermal Cycling ◽  
Vickers Hardness ◽  
Artificial Saliva ◽  
Acrylic Resin ◽  
Distilled Water ◽  
Posterior Teeth ◽  
Anterior Teeth ◽  
Denture Teeth ◽  
Occlusal Surfaces ◽  
Disinfectant Solution

Aim: The aim of this study was to evaluate the effect of artificial saliva, disinfectant solution, distile water and thermocycling on Vickers hardness of 4 commercial brands of acrylic resin denture teeth. Methodology: Four different brands of acrylic resin denture teeth (Major Dent, Acry Lux, Acry Rock, Imident Lux) were evaluated. 15 anterior and 15 posterior teeth of each group embedded in autopolymerized acrylic resin.  The occlusal surfaces of posterior teeth and the vestibule surfaces of anterior teeth were flattened by using silicone carbid paper. After polishing, microhardness measurements were repeated three times for each teeth. The teeth were submitted to different conditions: (1) storage in distilled water at 37±2°C for 7 days; (2) storage in artificial saliva at 37±2°C for 30 days and (3) storage in 1 % sodium hypochlorite. After, thermal cycling between 5 and 55 °C for 2500 cycles was made. The microhardness measurements were repeated. Data were analyzed with one-way analysis of variance (ANOVA) and Duncan test ( p<0.05). Results: There was statistical significant differences between initial and final microhardness values of different barnds of acrylic resin denture teet. Anterior teeth showed lower microhardness values than posterior teeth. Conclusion: Storage in different solutions and thermal cycling significantly reduced the Vickers hardness of the acrylic resin denture teeth.

scholarly journals Photoelastic Study of the Effects of Occlusal Surface Morphology on Tooth Apical Stress from Vertical Bite Forces

2004 ◽  
Vol 5 (1) ◽  
pp. 74-93 ◽  
Author(s):  
Mei-Qing Wang ◽  
Min Zhang ◽  
Jun-Hua Zhang
Keyword(s):  
Surface Morphology ◽  
Occlusal Surface ◽  
Posterior Teeth ◽  
Occlusal Contact ◽  
Test Assembly ◽  
Photoelastic Study ◽  
Normal Occlusion ◽  
Occlusal Surfaces ◽  
Mandibular Teeth ◽  
Relationship Of

Abstract The aim of the study was to determine how the morphology of occlusal surfaces might affect occlusal loading that is transferred to the tooth apex. Photoelastic methods were used to assess apical stress generated by seven variations of occlusions. A test assembly with a 2 kg weight was applied to teeth to create a vertical load. By analyzing the direction and magnitude of the apical principle stress under the polar light that was measured at the apexes of mandibular teeth, the occlusal loading position of each tooth and its direction was obtained based on general mechanical principles. It was found distal incline planes (or slopes) of cusps and lingual incline planes (or slope) of buccal cusps of mandibular posterior teeth carried the greatest occlusal load in normal occlusion. In the other six variations of occlusion presented in this study, the principle apical stresses changed more or less as a result of the different occlusal contact relationships. The magnitude of principle apical stress increased considerably in the flat surface occlusion because of the lack of distribution of occlusion loading by the smooth dentition surface. It is concluded the occlusal surface morphology has a significant effect on the direction and magnitude of apical stress. To establish a suitable relationship of occlusion that can conduct favorable occlusal loading physiologically is very important. Citation Wang M, Zhang M, Zhang J. Photoelastic Study of the Effects of Occlusal Surface Morphology on Tooth Apical Stress from Vertical Bite Forces . J Contemp Dent Pract 2004 February;(5)1:074-093.

scholarly journals Comprehensive approach to simultaneous molar intrusion and canine retraction in the treatment of Class II anterior open bite using miniscrew anchorage

2020 ◽  
Vol 25 (3) ◽  
Author(s):  
Kaori Shirasaki ◽  
Yoshihito Ishihara ◽  
Hiroki Komori ◽  
Takashi Yamashiro ◽  
Hiroshi Kamioka
Keyword(s):  
Treatment Duration ◽  
Class Ii ◽  
Open Bite ◽  
Prolonged Treatment ◽  
Anterior Open Bite ◽  
Posterior Teeth ◽  
Canine Retraction ◽  
Maxillary Molars ◽  
Anterior Teeth ◽  
Molar Intrusion

ABSTRACT Introduction: Anterior open bite is one of the most difficult malocclusions to correct in orthodontic treatment. Molar intrusion using miniscrew anchorage has been developed as a new strategy for open bite correction; however, this procedure still has an important concern about prolonged treatment duration in the patient with anteroposterior discrepancy due to the separate step-by-step movement of anterior and posterior teeth. Objective: This article illustrates a comprehensive orthodontic approach for dentoalveolar open bite correction of an adult patient, by using miniscrew. Case report: A woman 19 years and 5 months of age had chief complaints of difficulty chewing with the anterior teeth and maxillary incisor protrusion. An open bite of -2.0 mm caused by slight elongation of the maxillary molars was found. The patient was diagnosed with Angle Class II malocclusion with anterior open bite due to the vertical elongation of maxillary molars. After extraction of the maxillary first premolars, concurrent movements of molar intrusion and canine retraction were initiated with the combined use of sectional archwires, elastic chains and miniscrews. Results: At 4 months after the procedure, positive overbite was achieved subsequent to the intrusion of maxillary molars by 1.5 mm and without undesirable side effects. Class I canine relation was also achieved at the same time. The total active treatment period was 21 months. The resultant occlusion and satisfactory facial profile were maintained after 54 months of retention. Conclusion: The presented treatment shows the potential to shorten the treatment duration and to contribute to the long-term stability for open bite correction.

scholarly journals Negligible tooth resorptions after anterior open bite treatment using skeletal anchorage with miniplates

2020 ◽  
Vol 25 (4) ◽  
pp. 16-22
Author(s):  
Genivaldo dos Santos ◽  
Alberto Consolaro ◽  
Fernanda Meloti ◽  
Mauricio de Almeida Cardoso ◽  
Ertty Silva ◽  
...  
Keyword(s):  
Root Resorption ◽  
Open Bite ◽  
Dental Arch ◽  
Anterior Open Bite ◽  
Homogeneous Sample ◽  
Posterior Teeth ◽  
Anterior Teeth ◽  
Before And After ◽  
Applied Forces ◽  
External Apical Root Resorption

ABSTRACT Introduction: When miniplates are used as anchoring for orthodontic mechanics for anterior open bite correction by retraction of anterior teeth and posterior teeth intrusion and retraction, orthodontically induced inflammatory external apical root resorption is clinically negligible. Methods: A homogeneous sample of 32 patients was used, and the roots of the teeth were compared on CT scans performed before and after orthodontic treatment. Results: The observed root resorption was minimal, and this can be explained by the uniform distribution of forces in several teeth, simultaneously, in the set of the dental arch and in the bone that supports the teeth. Conclusion: The most important thing to prevent root resorption in orthodontic practice, besides being concerned with the intensity of the applied forces, is to be careful with its distribution along the roots of each tooth, in the dental arch and in the bone that supports the teeth.

scholarly journals Effects on the Dental Arch Form Using a Preadjusted Appliance with Premolar Extraction in Class I Crowding

2008 ◽  
Vol 78 (6) ◽  
pp. 1043-1049 ◽  
Author(s):  
Hironao Miyake ◽  
Tatsuo Ryu ◽  
Toshihiko Himuro
Keyword(s):  
Three Dimensional ◽  
Class I ◽  
Dental Arch ◽  
Arch Form ◽  
Premolar Extraction ◽  
Anterior Teeth ◽  
Quartic Polynomial ◽  
Before And After ◽  
Maxilla And Mandible ◽  
Dental Arch Form

Abstract Objective: To determine the dental arch form effects of treatment with a preadjusted appliance (0.022″ slot) performed concomitantly with extraction of premolars in Class I crowding. Materials and Methods: Twenty-six patients (20.17 ± 12.15 years) with Class I crowding who attained a favorable occlusion after treatment were divided into nonextraction and extraction groups. The three-dimensional coordinates of the FA point of each tooth were determined. The dental arch form was expressed as a quartic polynomial expression with log F value used to represent the dental arch form and calculated using the quadratic and quartic coefficients. Changes in the dental arch form before and after treatment were compared between the groups. Results: In the extraction group, log F value was significantly higher after treatment, and the upper dental arch became more tapered. The U1-APo was significantly lower after treatment. No change was observed in U1-FH. The anterior teeth demonstrated posterior movement due to sliding mechanics, and torque was controlled. The anterior length of the dental arch became significantly longer after treatment for the maxilla and mandible in both groups. Results demonstrated that the upper dental arch might become tapered after treatment used concomitantly with premolar extraction, as a result of the increase in anterior length while maintaining intercanine width for dealing with crowding of the anterior teeth. Conclusion: It is necessary to anticipate that the upper dental arch form will become tapered during extraction treatment for Class I crowding and to select an appropriate arch form.

scholarly journals Perawatan Cross Bite Posterior Unilateral Menggunakan Alat Ortodontik Cekat Teknik Begg

2015 ◽  
Vol 1 (2) ◽  
pp. 122
Author(s):  
Aditya Gungga K ◽  
Sri Suparwitri ◽  
Soekarsono Hardjono
Keyword(s):  
Female Patient ◽  
Class I ◽  
Median Line ◽  
Posterior Teeth ◽  
Lower Incisor ◽  
Fixed Appliance ◽  
Anterior Teeth ◽  
Left Posterior ◽  
Maxilla And Mandible ◽  
Occlusal Interferences

Cross bite merupakan kondisi dimana satu gigi atau lebih mengalami malposisi ke arah bukal atau lingual atau labial terhadap gigi antagonisnya. Cross bite dapat terjadi pada gigi anterior maupun posterior. Cross bite posterior dapat terjadi sebagai akibat kurangnya koordinasi dimensi lateral antara lengkung gigi rahang atas dan rahang bawah. Cross bite posterior dapat terjadi secara bilateral atau 2 sisi maupun unilateral atau 1 sisi. Berbagai penyebab cross bite posterior unilateral diantaranya adanya malposisi gigi ke lingual pada gigi rahang atas, adanya kebiasaan buruk seperti bertopang dagu satu sisi dan adanya pengaruh deviasi mandibula ketika menutup mulut. Tujuan artikel ini adalah menyajikan perawatan ortodontik cross bite posterior unilateral dengan teknik Begg. Pasien perempuan umur 19 tahun mengeluhkan gigi-gigi depan serta belakang atas dan bawah berjejal dan tidak nyaman untuk mengunyah. Diagnosis kasus adalah maloklusi Angle klas I, hubungan skeletal klas I dengan protrusif bimaksilar, protrusif bidental, crowding gigi anterior atas dan bawah, crowding gigi posterior atas kiri, edge to edge bite pada beberapa gigi anterior, cross bite antara gigi 22 dan 32, cross bite posterior unilateral pada sisi kanan, pergeseran rahang bawah kearah kiri, serta pergeseran midline gigi rahang bawah dan rahang atas kearah kiri.  Pasien dirawat menggunakan alat cekat teknik Begg. Koreksi cross bite dilakukan dengan ekspansi 1 sisi pada rahang atas kanan serta dengan pemasangan cross elastic untuk menarik gigi posterior bawah yang berada di luar lengkung. Setelah perawatan selama 11 bulan, cross bite posterior pada sisi kanan terkoreksi.   ABSTRACT: Unilateral posterior cross bite treatment using fixed orthodontic Begg appliance technique. Cross bite is a condition where one or more teeth may be abnormally malposed buccally or lingually or labially with reference to the opposing tooth or teeth. Cross bite can be classified based on location as anterior and posterior cross bite. Posterior cross bite occurs as result of lack of coordination in the lateral dimension between the upper and the lower arches. Posterior Cross bite can be unilateral involving one side of arch or bilateral which involves both sides. Posterior cross bite can be occur as result of a number of causes such us lingual positioning of upper tooth, presence of one side chin propped habit and presence of occlusal interferences can result in deviation of the mandible during jaw closure. The purpose of this articles to present unilateral posterior cross bite correction using Begg technique A 19 years old female patient complained of upper, lower front and back teeth crowded and uncomfortable for mastication. Diagnosis are malocclusion Angle Class I, Class I skeletal relationship with bimaksilar protrusive, upper and lower incisor retrusive, upper and lower anterior teeth crowding, upper left posterior teeth crowding, anterior edge to edge bite on several anterior tooth, anterior cross bite on 22 and 32, unilateral posterior cross bite on right side, shift to the left of mandible, shift to the left of the median line maxilla and mandible, The patien treated with fixed appliance Begg technique. One side expansion of maxilla on right side and posterior cross elastic are used to correct posterior cross bite. After 11 months of treatment, unilateral posterior cross bite on right side corrected.

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