Jaw Relation Record
Dimensional Measurement Accuracy
Jaw Diseases
Jaw Neoplasms
The development of the index of complexity, outcome and need (ICON). (1/90)
This paper is based on the winning submission for the 1998 Chapman prize awarded by the British Orthodontic Society for an essay on a subject promoting the interests of orthodontics. The aim of the investigation is to develop a single index for assessing treatment inputs and outcomes. An international panel of 97 orthodontists gave subjective judgements on the need for treatment, treatment complexity, treatment improvement, and acceptability on a diverse sample of 240 initial and 98 treated study models. The occlusal traits in the study models were scored according to a defined numerical protocol. Five highly predictive occlusal traits were identified (IOTN Aesthetic Component, crossbite, upper arch crowding/ spacing, buccal segment antero-posterior relationships, and anterior vertical relationship) and then used to 'predict' the panelist's decisions using regression analysis. Cut-off values were determined for the dichotomous judgements by plotting specificity sensitivity and overall accuracy. Twenty percentile ranges were used to determine 5 grades of complexity and improvement. The index prediction of decisions for treatment need, had specificity 84.4 per cent, sensitivity 85.2 per cent, and overall accuracy 85 per cent. When used to predict treatment outcomes, the new index had specificity 64.8 per cent, sensitivity 70.1 per cent, and overall accuracy 68.1 per cent. The index could explain 75.6 per cent of the variance in the mean casewise complexity score and 63.5 per cent of the mean casewise improvement score. A new orthodontic index is proposed to assess treatment need, complexity, and outcome. It is based on international orthodontic opinion. (+info)A validation of two orthognathic model surgery techniques. (2/90)
In order to create an evidence-based orthognathic surgery planning protocol, an investigation of two popular model surgery techniques, the Lockwood keyspacer and the Eastman anatomically-orientated system was carried. This determined (a) the accuracy of positioning of the maxillary cast according to the prescribed treatment plan and (b) the relocation of the maxilla after a simulated Le Fort I down fracture osteotomy using the intermediate wafer as a guide. Fifteen patients-five Class II division 1, five Class II division 2, and five Class III-were included in the study. All the measurements were taken with Erickson's vertically mounted electronic caliper and variations from the treatment plan were analysed. The mean model surgery positioning errors +/- SD (mm) were: (i) vertical plane-Lockwood -0*8 +/- 1*6 and Eastman 0*00 +/- 1*0 (P = 0*0001); (ii) anteroposterior plane-Lockwood 1*2 +/- 1*8 and Eastman -0*1 +/- 1*4 (P = 0*05); and (iii) transverse plane-Lockwood 0*9 +/- 0*9 and Eastman 1*0 +/- 0*9 (P = 0*34). After the simulated osteotomy, the mean errors +/- SD were: (i) vertical plane-Lockwood -0*5 +/- 1*5 and Eastman 0*3 +/- 1*1 (P = 0*001); (ii) in anteroposterior plane-Lockwood 0*8 +/- 2*0 and Eastman 0*7 +/- 1*0 (P = 0*89); and (iii) transverse plane-Lockwood 0*8 +/- 0*6 and Eastman 0*7 +/- 0*5 (P = 0*83). The Eastman technique was relatively better especially in the vertical plane. The variations from the treatment plan were on the whole anatomically small, but in some cases could be clinically significant. (+info)Functional occlusion: II. The role of articulators in orthodontics. (3/90)
Opinion is divided on whether there is a place for the use of semi-adjustable dental articulators in orthodontics. In this review we explore the validity and reproducibility of the techniques involved in mounting study models on a semi-adjustable dental articulator. We also look at the role of articulated study models in orthodontic diagnosis and treatment planning, in the finishing stages of orthodontics and in planning for orthognathic surgery. We report that each of the many stages involved in mounting study models on a semi-adjustable articulator is a potential source of error and that only if the technique is carried out with a high degree of accuracy is it worth the additional chairside time. (+info)Craniofacial morphology of Japanese girls with Class II division 1 malocclusion. (4/90)
OBJECTIVE: To identify the craniofacial features of Japanese girls with Class II division 1 malocclusions. METHOD: One hundred and ninety lateral cephalometric radiographs were analysed, and the subjects whose age ranged from 7 years 6 months to 15 years 10 months were divided into three groups by their dentition: middle mixed dentition, late mixed dentition, and early permanent dentition. The mean values of 5 linear and 16 angular cephalometric parameters were compared with established Japanese Class I control values. RESULTS: Japanese girls with Class II division 1 malocclusion had a significantly small S-N-B angle (p < 0.001), short mandibular ramus (p < 0.05-0.001), and a large mandibular plane angle (p < 0.05-0.001). CONCLUSION: Japanese girls with Class II division 1 malocclusion had a high-angle facial pattern associated with the short mandibular ramus. (+info)The examination and recording of the occlusion: why and how. (5/90)
Before presenting 'how' the examination and recording of the occlusion may be achieved, some attempt should be made to justify 'why' it is necessary. It may appear to be a strange way of justifying the need to examine the patient's occlusion, but this will initially involve a study of the influences of mandibular movements. (+info)Good occlusal practice in simple restorative dentistry. (6/90)
Many theories and philosophies of occlusion have been developed. 1-12 The difficulty in scientifically validating the various approaches to providing an occlusion is that an 'occlusion' can only be judged against the reaction it may or may not produce in a tissue system (eg dental, alveolar, periodontal or articulatory). Because of this, the various theories and philosophies are essentially untested and so lack the scientific validity necessary to make them 'rules'. Often authors will present their own firmly held opinions as 'rules'. This does not mean that these approaches are to be ignored; they are, after all, the distillation of the clinical experience of many different operators over many years. But they are empirical. In developing these guidelines the authors have unashamedly drawn on this body of perceived wisdom, but we would also like to involve and challenge the reader by asking basic questions, and by applying a common sense approach to a subject that can be submerged under a sea of dictate and dogma. (+info)Good occlusal practice in advanced restorative dentistry. (7/90)
In most patients the existing occlusal scheme will be functional, comfortable and cosmetic; and so if a tooth or teeth need to be restored, the most appropriate way to provide the restoration(s) would be to adopt a 'conformative' approach: that is to provide treatment within the existing envelope of static and dynamic occlusal relationships. There will, however, be situations where the conformative approach cannot be adopted, and this section aims to describe what is 'Good Occlusal Practice' in these circumstances. (+info)Good occlusal practice in removable prosthodontics. (8/90)
The loss of teeth may result in patients experiencing problems of a functional, aesthetic and psychological nature. This section addresses the very important subject of occlusal considerations for partial and complete dentures. The occlusion is particularly important given the bearing that occlusal factors have, especially on edentulous patients. (+info)A Jaw Relation Record (also known as a "mounted cast" or "articulated record") is a dental term used to describe the process of recording and replicating the precise spatial relationship between the upper and lower jaws. This information is crucial in various dental treatments, such as designing and creating dental restorations, dentures, or orthodontic appliances.
The Jaw Relation Record typically involves these steps:
1. Determining the optimal jaw position (occlusion) during a clinical procedure called "bite registration." This is done by using various materials like waxes, silicones, or impression compounds to record the relationship between the upper and lower teeth in a static position or at specific movements.
2. Transferring this bite registration to an articulator, which is a mechanical device that simulates jaw movement. The articulator holds dental casts (replicas of the patient's teeth) and allows for adjustments based on the recorded jaw relationship.
3. Mounting the dental casts onto the articulator according to the bite registration. This creates an accurate representation of the patient's oral structures, allowing dentists or technicians to evaluate, plan, and fabricate dental restorations that will fit harmoniously in the mouth and provide optimal function and aesthetics.
In summary, a Jaw Relation Record is a critical component in dental treatment planning and restoration design, as it captures and replicates the precise spatial relationship between the upper and lower jaws.
Dimensional measurement accuracy refers to the degree of closeness with which the measured dimension of a object or feature corresponds to its true value. It is usually expressed as a tolerance, which indicates the maximum allowable deviation from the true value. This measurement accuracy can be affected by various factors such as the precision and calibration of the measuring instrument, the skill and experience of the person taking the measurement, and environmental conditions such as temperature and humidity. High dimensional measurement accuracy is essential in many fields, including manufacturing, engineering, and scientific research, to ensure that parts and products meet specified dimensions and function properly.
In medical terms, the jaw is referred to as the mandible (in humans and some other animals), which is the lower part of the face that holds the lower teeth in place. It's a large, horseshoe-shaped bone that forms the lower jaw and serves as a attachment point for several muscles that are involved in chewing and moving the lower jaw.
In addition to the mandible, the upper jaw is composed of two bones known as the maxillae, which fuse together at the midline of the face to form the upper jaw. The upper jaw holds the upper teeth in place and forms the roof of the mouth, as well as a portion of the eye sockets and nasal cavity.
Together, the mandible and maxillae allow for various functions such as speaking, eating, and breathing.
Jaw diseases refer to a variety of conditions that affect the temporomandibular joint (TMJ) and the surrounding muscles, as well as dental disorders that can impact the jaw. Some common examples include:
1. Temporomandibular Joint Disorders (TMD): These are problems with the TMJ and the muscles that control jaw movement. Symptoms may include pain, clicking or popping sounds, and limited movement of the jaw.
2. Osteonecrosis of the Jaw: This is a condition where bone in the jaw dies due to lack of blood supply. It can be caused by radiation therapy, chemotherapy, or certain medications.
3. Dental Cavities: These are holes in the teeth caused by bacteria. If left untreated, they can cause pain, infection, and damage to the jawbone.
4. Periodontal Disease: This is an infection of the gums and bones that support the teeth. Advanced periodontal disease can lead to loss of teeth and damage to the jawbone.
5. Jaw Fractures: These are breaks in the jawbone, often caused by trauma.
6. Oral Cancer: This is a type of cancer that starts in the mouth or throat. If not treated early, it can spread to the jaw and other parts of the body.
7. Cysts and Tumors: These are abnormal growths in the jawbone or surrounding tissues. While some are benign (non-cancerous), others can be malignant (cancerous).
8. Osteomyelitis: This is an infection of the bone, often occurring in the lower jaw. It can cause pain, swelling, and fever.
9. Oral Thrush: This is a fungal infection that causes white patches on the inside of the mouth. If left untreated, it can spread to the jaw and other parts of the body.
10. Sinusitis: Inflammation of the sinuses can sometimes cause pain in the upper jaw.
Jaw neoplasms refer to abnormal growths or tumors in the jawbone (mandible) or maxilla (upper jaw). These growths can be benign (non-cancerous) or malignant (cancerous). Benign neoplasms are not considered life-threatening, but they can still cause problems by invading nearby tissues and causing damage. Malignant neoplasms, on the other hand, can spread to other parts of the body and can be life-threatening if not treated promptly and effectively.
Jaw neoplasms can present with various symptoms such as swelling, pain, loose teeth, numbness or tingling in the lips or tongue, difficulty chewing or swallowing, and jaw stiffness or limited movement. The diagnosis of jaw neoplasms typically involves a thorough clinical examination, imaging studies such as X-rays, CT scans, or MRI, and sometimes a biopsy to determine the type and extent of the tumor.
Treatment options for jaw neoplasms depend on several factors, including the type, size, location, and stage of the tumor, as well as the patient's overall health and medical history. Treatment may involve surgery, radiation therapy, chemotherapy, or a combination of these modalities. Regular follow-up care is essential to monitor for recurrence or metastasis (spread) of the neoplasm.
Jaw abnormalities, also known as maxillofacial abnormalities, refer to any structural or functional deviations from the normal anatomy and physiology of the jaw bones (mandible and maxilla) and the temporomandibular joint (TMJ). These abnormalities can be present at birth (congenital) or acquired later in life due to various factors such as trauma, infection, tumors, or degenerative diseases.
Examples of jaw abnormalities include:
1. Micrognathia: a condition where the lower jaw is underdeveloped and appears recessed or small.
2. Prognathism: a condition where the lower jaw protrudes forward beyond the normal position.
3. Maxillary hypoplasia/aplasia: a condition where the upper jaw is underdeveloped or absent.
4. Mandibular hypoplasia/aplasia: a condition where the lower jaw is underdeveloped or absent.
5. Condylar hyperplasia: a condition where one or both of the condyles (the rounded ends of the mandible that articulate with the skull) continue to grow abnormally, leading to an asymmetrical jaw and facial deformity.
6. TMJ disorders: conditions affecting the temporomandibular joint, causing pain, stiffness, and limited movement.
7. Jaw tumors or cysts: abnormal growths that can affect the function and structure of the jaw bones.
Jaw abnormalities can cause various problems, including difficulty with chewing, speaking, breathing, and swallowing, as well as aesthetic concerns. Treatment options may include orthodontic treatment, surgery, or a combination of both, depending on the severity and nature of the abnormality.