Article information. Sections: Radiography , Approach. Tags: shetty , definition , terminology. Synonyms or Alternate Spellings: X-ray positions.
Figure 1: anatomical planes illustration Figure 1: anatomical planes illustration. Figure 2: anatomical relations illustration Figure 2: anatomical relations illustration. Loading more images This concept is based on the observation that NWS contacts were destructive  and therefore the teeth on the NWS should be free of any ececntric contacts, and instead the contacts should be distributed on the WS thus sharing the occlusal load. Group function is used when canine guidance cannot be achieved and also in the Pankey-Mann Schuyler PMS approach where it was deemed better than canine guidance as it distributed the loading on the WS better.
In eccentric movements, damaging forces are applied to the posterior teeth and the anteriors are best suited to receiving these. Therefore during protrusive movements, the contact or guidance of the anteriors should be adequate to disocclude and protect the posterior teeth. In contrast, the posterior teeth are more suited to accept the forces that are applied during closure of the mandible.
This is because the posteriors are positioned so the forces are applied directly along the long axis of the tooth and are able to dissipate them efficiently whereas the anteriors cannot accept these heavy forces as well due to their labial positioning and angulation. It is therefore accepted that the posterior teeth should have heavier contacts than the anteriors in ICP and act as a stop for vertical closure.
Additionally, in lateral excursions either canine or group function should act to disclude the posterior teeth on the WS because, as described above, the anterior teeth are best suited to dissipate damaging horizontal forces, as well as the contact being further away from the TMJ, so the forces created are decreased in strength. Group function or canine guidance should also provide disocclusion of the teeth on the NWS as the amount and direction of force applied to the TMJ and teeth can be destructive due to an increase in muscle activity.
A deflective contact is a contact that diverts the mandible from its intended movement. This is often involved in function e. An occlusal interference is any tooth contact that prevents, or hinders harmonious mandibular movement an undesirable tooth contact.
The occlusal interferences may be classified as follows: . When the dentist is providing restorations, it is important that these do not create an interference, otherwise the restoration will receive increased loading. As for deflective contacts, interferences may also be associated with parafunction such as bruxism although evidence is weak and may adversely affect the distribution of heavy occlusal forces. Interferences may also cause pain in the masticatory muscles due to altering their activity,  however there is large controversy and debate as to whether there is a relationship between occlusion and temporomandibular disorders.
Almost all dentate individuals have occlusal interferences, and therefore they are not seen to be an etiology of all TMDs. When there is an acute change or significant instability in the occlusal condition and subsequently represents an etiological factor for a TMD, occlusal treatment is required.
Occlusal adjustment removal of occlusal interferences may be carried out in order to obtain a stable occlusal relationship and is achieved by selectively grinding the occlusal interferences or through wear of a hard occlusal splint to ensure true retruded relationship is established. When there is an absence of symptoms and the masticatory system is functioning efficiently, the occlusion is considered normal or physiological.
However, an optimal functional occlusion is important to consider when providing restorations as this helps to understand what is trying to be achieved. It is defined in established texts  as:. It is necessary to understand the concepts that influence the function and health of the masticatory system in order to prevent, minimise or eliminate any breakdown or trauma to the TMJs or teeth.
There are various factors that play a role in the adaptive capability of a patient with regards to changes in occlusion. Factors such as the central nervous system and the mechanoreceptors in the periodontium , mucosa and dentition are all of importance here.
It is in fact, the somatosensory input from these sources that determines whether an individual is able to adapt to changes in the occlusion, opposed to the occlusal scheme itself. It is thought that patients who are increasingly vigilant to any changes in the oral environment are less likely to adapt to any occlusal changes. Psychological and emotional stress can also contribute to the patient's ability to adapt as these factors have an impact on the central nervous system.
In individuals with unexplained pain, fracture, drifting, mobility and tooth wear, a full occlusal examination is vital. Similarly when complex restorative work is planned it is also essential to identify whether any occlusal changes are required prior to the provision of definitive restoration  In some people even minor discrepancies in the occlusion can lead to symptoms involving the TMJ or acute orofacial pain so it is important to identify and eradicate this cause.
The examination should be carried out using a systematic approach whilst assessing the following:. The facial height of the patient should be considered and it should be noted where there may have been a loss.
Begin by simply palpating the muscles concerned with the occlusion of the teeth. These muscles include the muscles of mastication and other muscles within the head and neck area, such as the supra-hyoid muscles. It is best to palpate the muscles simultaneously and bilaterally. TMJ disorders can be detected through occlusal examination.
Ask the patient to open and close whilst placing two fingers over the space of the TMJ. Opening of less than 35mm in the mandible is considered to be restricted and such restriction may be associated with intra-capsular changes within the joint. Note any clicking, crepitus, pain or deviation. Assess each arch and identify whether there are any signs of occlusal disharmony, overloading, tooth migration, wear, craze lines, cracking or mobility not due to periodontal causes.
Begin by assessing the incisor and molar relationship as described above. Similarly examine the overbite and overjet. An overbite of mm  and an overjet of mms are considered to be within the range of normal. To look at the ICP, articulating paper should be placed on the occlusal surface and the patient asked to bite together, which will mark their occlusal contacts.
CD represents the height of the www. It is significantly 36, triangular in 65 and rounded in 28 mandibles. Other sides of the coronoid process are also hook shaped types were the most and the least longer as side AC in male is The coronoid process is of which is drawn on the sides of the coronoid clinical significance to the maxillofacial surgeons process, it is Tapas  reported female it is All the sides of the that triangular shaped coronoid process was found coronoid process are longer in male than in female.
She showed that than the coronoid process of female. From the triangular shaped of the coronoid processes were measurements of the coronoid process we can most prevalent followed by hook shaped and assess the sex the mandible even from its fragments rounded. This is due to 3. The triangular shaped is more prevalent in eating and chewing habit.
Mostly the persons eat male They shown in The mandible is the strong and largest bone of the their study that triangular shaped was more face.
It is having arched body, two rami, two commonly present in males while female presented coronoid processes and two condyloid processes. Standring , described the coronoid process as a Desai et al  showed that the shapes of coronoid flat triangular process. Hossain et al. Mahajan et al  Pradhan et al. Hook Khan et al. Prajapat et al. Mahajan et al. Bakirci et al. Tapas Desai et al. Present study Use In the present study the types of the coronoid of Coronoid Process as a Donor site for Sinus process found were, triangular type The Int J Oral shaped The Maxillofac Implants.
Morphometric maxillofacial surgeons and plastic surgeons for Characteristics and Typology of the Coronoid reconstructive purposes as it is used as graft in process of the Mandible. Acta Medica reconstruction of osseous defects in oral and facio- Medterranea.
A classification of Class II Division 1 malocclusion. Renfroe EW. Rothstein TL. Facial morphology and growth from 10 to 14 years of age in children presenting Class II, Division 1 malocclusion: A comparative roentgenographic cephalometric study. Am J Orthod. McNamara JA. Components of class II malocclusion in children years of age. Schmuth GP.
Milestones in the development and practical application of functional appliances. Teuscher U. A growth-related concept for skeletal class II treatment. Clark WJ. The twin-block technique. Jakobsson SO. Bjork A. The principle of the Andresen method of orthodontic treatment a discussion based on cephalometric x-ray analysis of treated cases. The effect of activator treatment on class II malocclusions.
Calvert FJ. An assessment of Andresen therapy on class II division 1 malocclusion. Br J Orthod. A laminographic study of alterations in the temporomandibular joint following activator treatment. Eur J Orthod. Luder HU. Skeletal profile changes related to two patterns of activator effects. Reey RW , Eastwood A. The passive activator: Case selection, treatment response, and corrective mechanics.
Vargervik K , Harvold EP. Response to activator treatment in Class II malocclusions. Results of Class II functional appliance treatment. J Clin Orthod. Ascher F. Removable Orthodontic Appliances. Philadelphia: W. Saunders ; The twin block traction technique. The present study compared with the standard literature and studies done by other authors. This is helpful for maxillofacial surgeons, anthropologists, traumatologists, forensic odontology and forensic medicine for the determination of sex from the fragment of the mandible.
Key words: Mandible, condyloid process, maxillofacial surgeons, fracture, grafting, forensic medicine, fragment, traumatologist. Correspondence Address: Dr. Please cite this article in press as Dr.
It has arched body, two broad rami, two condyloid processes and two coronoid processes. The coronoid process projects upwards and slightly forwards as a triangular plate of bone. Its posterior border bounds the mandibular incisura and its anterior border continues as the anterior border of the ramus. It is a triangular, thin flat, eminent bony projection of the ramus of the mandible.
The coronoid process provides the insertion to the muscle of mastication i. The coronoid process is rarely significantly displaced because it is splinted by the tendinous insertion of temporalis muscle [1,2]. Various authors have described the various shapes of the coronoid process. According to Issac and Holla , Prajapari  and Khan and Sharieff  the process is triangular, hook shaped and rounded. The shape and size of the coronoid process is influenced by dietary habit, genetic constitution, hormonal and the most important is the activity of temporalis muscle.
Bakirci  stated in their study that the human skeletal features are valuable for both clinical applications and determinations of racial characteristics of the different populations.
Use of bone and bone fragments is also important for forensic sciences for the race, sex and weight of the body related estimations. Autologous, allograft or synthetic bone grafts can be obtained by different approaches.
In this way, complications such as infection, bleeding, and tissue damage is lower than allografts and so this method is preferred by surgeons. The coronoid process is of clinical significance to the maxillofacial surgeons for reconstructive purposes Shakya . Autogenous bone grafts can be obtained from ilium, rib and calvarias; but each site has its own associated morbidity. A local bone graft from the coronoid process of the mandible can be used as it can be harvested easily, minimal morbidity, shorter surgical and hospitalization time, no cutaneous scarring as bone is harvested intraorally.
A coronoid process graft can be used for alveolar defects repair, orbital floor repair, maxillary augmentation, repair of non-union fracture of mandible.
The coronoid process also has been used as a donor site for sinus augmentation . The mandibles having deformed coronoid process were discarded. The shapes of the coronoid process were counted, noted, recorded and photographed.
For the measurement of the size of the coronoid process, the points were marked on the lowest point of the mandibular notch. Noted its distance from the base of the mandible. At the same height, a point will be marked on the anterior border of the ramus of the mandible. At the same height from the base of the mandible a point will be marked on the posterior border of the ramus. A line will be drawn to meet these points.
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