The features that constitute an "ideal" functional occlusion have not been conclusively established. Orthodontic treatment has the capacity to change static and functional occlusal relationships fundamentally. In this article, we present the evidence on which features of the occlusion are reported to be detrimental to the teeth and masticatory system Deficiencies in this research area are highlighted, together with the need for prospective longitudinal trials to clarify the requirements of an ideal functional occlusion Based on the existing evidence this paper suggests which occlusal features may be significant in producing an "ideal" functional occlusion As no long-term studies exist to measure the impact of non-ideal occlusal relationships on the dentition, it is debatable whether orthodontic treatment should be prolonged in order to ensure that "ideal" occlusal contacts are achieved As the occlusion tends to "settle" in the period following appliance removal, we propose that it may be more appropriate to examine the functional occlusal relationships after retention has ceased rather than prolong active orthodontic treatment to achieve "ideal" functional occlusal goals. (+info)
What is occlusion?
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The aim of this series of papers is to explore the role of occlusion in dental practice. The range of opinion in the dental profession as to the importance of occlusion is enormous. It is very important that the profession in general and practising dentists in particular have a balanced view of occlusion. This is more important than every patient having a balanced occlusion. The fact that the study of occlusion is characterised by extremes makes it confusing and possibly difficult for individual dentists to find a philosophy which is in line with contemporary good practice supported by evidence from practice-based research. (+info)
The examination and recording of the occlusion: why and how.
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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 removable prosthodontics.
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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)
Occlusal interferences in orthodontic patients before and after treatment, and in subjects with minor orthodontic treatment need.
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Different opinions have been expressed concerning the effect of orthodontic treatment on mandibular function. One factor discussed is occlusal interferences. The aim of this study was to establish the prevalence of occlusal interferences in 210 orthodontic patients before (mean age 12 years 8 months) and after (mean age 16 years 10 months) treatment and to compare them with subjects with minor orthodontic treatment need. The results showed a decrease in retruded contact position/intercuspal position (RCP/ICP) interferences in all morphological deviations, age, and gender groups. The prevalence of mediotrusion interferences decreased in some types of malocclusions whilst in others there was no change. One reason for this is that treatment was started when the majority of the patients had no second or third molars erupted. At the final registration, the second molars were erupted in all patients, and the third molars were erupted in approximately 25 per cent. Mediotrusion interferences were more consistent with basal morphological deviations, for example, Class III relationships and anterior open bite were more consistent in the same person, and more difficult to eliminate than RCP/ICP interferences. RCP/ICP interferences, often caused by dental deviation in position, size, and shape, were easier to correct. Optimal orthodontic treatment, if necessary, including selective grinding, will decrease the prevalence of occlusal interferences. (+info)
Can temporomandibular dysfunction signs be predicted by early morphological or functional variables?
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The aim of the present study was to establish whether the early signs of various orofacial dysfunctions, malocclusions, or occlusal interferences can predict the development of temporomandibular dysfunction (TMD) in young adults. Forty-eight subjects referred for speech therapy and 49 controls participated in all four stages of this longitudinal study. The subjects were examined at the ages of 7, 10, 15, and 19 years. The phoniatrician diagnosed errors in place of articulation and problems in the movement and co-ordination of the speech articulators. Occlusion, TMD signs (palpatory tenderness of the masticatory muscles, and of temporomandibular joints (TMJ), jaw deviation on opening, and clicking), mandibular movement capacity and occlusal interferences were registered by the orthodontist. Multiple logistic regression models were applied in order to evaluate whether single signs of TMD at the age of 19 years were related to previous/present malocclusions or interferences, to misarticulations of speech, problems in oral motor skills, or other signs of TMD. The effect of gender was also considered. The results showed that excessive overjet was the only variable which seemed to consistently increase the risk of TMD. In addition, girls seemed to be more prone to the development of TMD than boys. Although, during growth, there were both local and central factors associated occasionally with TMD development, the predictive value of those variables in the estimation of the individual risk of TMD was rather small. (+info)
Axiographic findings in patients undergoing orthodontic treatment with and without premolar extractions.
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Mechanical axiography was performed on 49 (37 female, 12 male) patients prior to orthodontic treatment, after removal of the fixed appliance, and at the end of retention. Twenty-five subjects (mean age 12.8 years) underwent orthodontic treatment without premolar extractions (group 1) and 24 subjects (mean age 13.5 years) with premolar extractions (group 2). The axiographic tracings of the protrusive movements were analysed using a digitizer and specially designed software. A statistically significant increase (P < 0.05) in the values for horizontal condylar inclination (HCI) was found for both groups over the entire observation period. Group 1 showed a higher increase (P < 0.05) between the beginning of treatment and removal of the brackets, and group 2 between bracket removal and the end of retention. At the end of retention, a similar increase in HCI values was found for both groups. Over the observation period, the frequency of pathological axiographic findings decreased, which seems to be a positive effect of orthodontic treatment. (+info)
Molar bite force in relation to occlusion, craniofacial dimensions, and head posture in pre-orthodontic children.
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The present study examined bite force in relation to occlusion, craniofacial dimensions, and head posture. The sample comprised 88 children (48 girls, 40 boys) aged 7-13 years, sequentially admitted for orthodontic treatment of malocclusions entiling health risks. Bite force was measured in the molar region by means of a pressure transducer. Angle classification, number of teeth and contact in the intercuspal position (ICP) were recorded and dental arch widths were measured on plaster casts. Craniofacial dimensions and head posture were recorded from lateral cephalometric radiographs taken with the subject standing with their head in a standardized posture (mirror position). Associations were assessed by Spearman correlations and multiple stepwise regression analyses.The maximum bite force increased significantly with age in girls, with teeth in occlusal contact in boys, and with increasing number of erupted teeth in both genders. Bite force did not vary significantly between the Angle malocclusion types. Only in boys was there a clear correlation between bite force and craniofacial morphology: cranial base length (n-ba, n-ar), posterior face height (s-tgo, ar-tgo), vertical jaw relationship (NL-ML), mandibular inclination (NSL-ML), form (ML-RL) and length (pg-tgo), and inclination of the lower incisors (Ili-ML). Multiple regression analysis showed that the vertical jaw relationship (P < 0.001) and the number of teeth present (P < 0.01) were the most important factors for the magnitude of bite force in boys. In girls, the most important factor was the number of teeth present (P < 0.001). No correlations between bite force and head posture were found. (+info)