Tooth mobility measurements following two methods of eliminating nonworking side occlusal interferences

Abstract The objective of this study was to compare tooth mobility following two methods of eliminating nonworking side interference (NWSI). The first method involved the complete elimination of any tooth contact on the NWS. The second method involved the reduction of the NWSI to a level which was harmonious with the occlusion on the working side. Thirty-three clinically healthy individuals having nonworking side interferences and no pathological signs of occlusal trauma, participated in the study. After 1 month of intensive training in oral hygiene, the volunteers were divided into three groups of 11 each. The first two groups were experimental and the third group received no occlusal adjustment to serve as a control. In the first group tooth mobility measurements and periapical x-ray films of teeth with nonworking interferences were taken. Occlusal interferences were then totally eliminated by selective tooth grinding. Two months later mobility and x-ray recordings of same teeth were repeated. In the second group the same procedure was performed, but nonworking side interferences were adjusted to harmonious contacts with occlusion on the working side. Tooth mobility was measured in hundredths of a millimeter, using the microperiodontometer designed by Mühlemann (1954). Data were subjected to statistical analysis and the following conclusions were drawn:

• 1 Tooth mobility was significantly (P < 0.001) reduced after complete elimination of nonworking side interferences, as well as after adjusting the nonworking side interferences to harmonious contacts with occlusion on the working side (P < 0.01).
• 2 The reduction in mobility was significantly (P < 0.001) greater when occlusal interferences were completely eliminated than when harmonious contacts were achieved.
• 3 There were no detectable radiographic changes, either in the interproximal alveolar bone level or periodontal ligament spaces, 2 months following occlusal adjustment.

     

Nonfunctional and functional occlusal contacts: a review of the literature.

A review of the literature on occlusal contacts emphasizes the following points. 1. Contacts in centric occlusion do not correspond to any ideal occlusal diagram. 2. Canine protection and group function appear to correspond to two successive states of the evolving dentition under the effect of abrasion. In most lateral occlusions, two maxillary teeth, of which one is the canine, are involved. 3. During mastication, tooth contacts exist. They occur most often during a sliding movement in which the direction and the origin are variable. This justifies the concept of an occlusal field of mastication. 4. During unilateral mastication, the chewing of the food is performed by working as well as nonworking contact. This imposes the distinction between the chewing and nonchewing sides (functional) and the working and nonworking sides (kinematic). 5. Centric occlusion is the occlusion most often used during mastication. It is also the occlusion for which the masticatory forces are the greatest. 6. The bibliographic data concerning occlusal contracts during swallowing are largely contradictory. It nevertheless seems that the occlusal contacts obey laws nearly the same as those governing the occlusal contact during mastication (sliding on an occlusal field of deglutition, and the importance of centric occlusion).     

A possible biomechanical role of occlusal cusp–fossa contact relationships

Summary Biomechanical features of occlusal contacts are important in understanding the role of the occlusion contributing to masticatory function. Cusp–fossa contact is the typical pattern of occlusion between upper and lower teeth. This includes static relations, such as that during clenching, and dynamic relations when mandibular teeth contact in function along the maxillary occlusal pathways, as during mastication. During clenching in the maximum intercuspal position (ICP), cuspal inclines may take the role of distributing the occlusal forces in multi‐directions thus preventing excessive point pressures on the individual tooth involved. During chewing movement on the functional side, the mandible moves slightly from buccal through the maximum ICP to the contralateral side. The part of the chewing cycle where occlusal contacts occur and the pathways taken by the mandible with teeth in occlusal contacts are determined by the morphology of the teeth. The degree of contact is associated with the activity of the jaw muscles. To obtain repeatable static and dynamic occlusal contact information provided by the morphology of the teeth, maximum voluntary clenching and chewing movements with maximum range are needed. In conclusion, in addition to the standard occlusal concepts of centric relation/centric occlusion and group function/cuspid protection relation, biomechanics in static and dynamic cusp–fossa relationships should be included to develop an understanding of occlusal harmony which includes no interfering or deflective contacts in functional occlusal contact.     

Clinical diagnosis of trauma from occlusion and its relation with severity of periodontitis

The purpose of the present study was to determine the reliability of several selected signs of trauma from occlusion and their relations with severity of periodontitis. 32 moderate to advanced chronic periodontitis patients participated in the study. All teeth present were evaluated for various abnormal occlusal contacts, signs of trauma from occlusion, and the severity of periodontitis. Standardized periapical radiographs were also taken for each tooth. The results demonstrated that: (1) no significant difference occurred in probing pocket depth (PD), clinical attachment loss (AL), or percentage of alveolar bone height (BH) between teeth with and without various abnormal occlusal contacts, i.e., premature contacts in centric relation occlusion, non-working contacts in lateral excursions, premature contacts of anterior teeth or posterior protrusive tooth contacts; (2) teeth with either significant mobility, functional mobility, or radiographically widened periodontal ligament space (PDLS) had deeper PD, more AL and lower BH than teeth without these signs, while teeth with pronounced wear or radiographically thickened lamina dura had less AL than teeth without these findings; (3) 2 combined indices, i.e., the trauma from occlusion index (TOI) and the adaptability index (AI), were proposed for the identification of occlusal trauma and the response of periodontium to excessive biting forces in heavy function, respectively; TOI-positive teeth exhibit deeper PD, more AL and less osseous support than TOI-negative teeth; however, AI-positive teeth had less AL and more osseous support than AI-negative teeth; (4) with identical attachment level, TOI-positive teeth had less osseous support than TOI-negative teeth while the magnitude of difference became greater with an increase of attachment loss.     

Association between signs of trauma from occlusion and periodontitis

The purpose of this study was to evaluate the association between signs of trauma from occlusion, severity of periodontitis and radiographic record of bone support. The maxillary first molars of 300 individuals were independently evaluated by two examiners for signs of trauma from occlusion, pattern or occlusal contacts and severity of periodontitis. Each site was also evaluated radiographically by an independent third examiner. The results indicated that: teeth with either bidigital mobility, functional mobility, a widened periodontal ligament space or the presence of radiographically visible calculus had a deeper probing depth, more loss of clinical attachment and less radiographic osseous support than teeth without these findings, teeth with occlusal contacts in centric relation, working, nonworking or protrusive positions did not exhibit any greater severity of periodontitis than teeth without these contacts, teeth with both functional mobility and radiographically widened periodontal ligament space had deeper probing depth, more clinical attachment loss and less radiographic osseous support than teeth without these findings and given equal clinical attachment levels, teeth with evidence of functional mobility and a widened periodontal ligament space had less radiographic osseous support than teeth without these findings.     

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目的比较Ⅰ、Ⅱ、Ⅲ类错验及正畸治疗后患者与个别正常验的咬合力差异,为正畸临床诊断和术后稳定性评价提供参考。方法于2006年1月至2008年12月选择来大连大学附属口腔医院正畸科就诊的无正畸治疗史的Ⅰ、Ⅱ、Ⅲ类错铪患者110例及正畸治疗后患者42例,另选择个别正常矜志愿者28名。采用T-ScanⅡ咬合力分析系统,对其[牙合]力总值进行比较分析。结果Ⅰ、Ⅱ、Ⅲ类错[牙合]的验力总值均低于个别正常[牙合]（P〈0．05）;正畸治疗后患者虽获得良好的咬合关系,[牙合]力总值增加,但与个别正常[牙合]比较,差异仍有统计学意义（P〈0．05）。结论正畸治疗可改善咬合关系,增加[牙合]力总值,但与个别正常[牙合]的[牙合]力总值仍有差异,推断牙齿在建立良好的咬合关系后,仍需要一定时间的咬合面磨合、神经肌肉的改建,才能更好地发挥咬合功能。     

侧方咬合运动中接触型及其分布特征

目的观察侧方咬合运动中接触点的分布特征,并对尖牙尖对尖颌位时的侧方型进行分类。方法利用T-ScanII咬合分析系统记录85名个别正常者侧方咬合运动过程中的接触信息,并进行统计分析。结果尖牙尖对尖颌位时的接触形式有六类:尖牙保护(44.1%)、组牙功能(20.6%)、工作侧多组前牙接触(2.9%)、仅工作侧第一前磨牙接触(8.8%)、工作侧前后牙同时存在接触(20.0%)、工作侧非工作侧同时存在接触(3.5%)。结论自然牙列侧方接触形式除尖牙保护与组牙功能外还存在其它一些型。     

Occlusal control of mandibular elevator muscles

Occlusal stability and mandibular elevator muscle function was studied in 25 women (20–30 yr of age). They had 27–32 fully erupted teeth with few treated occlusal surfaces, and craniomandibular function including mandibular mobility was normal. The aim was to analyze the influence of natural patterns of occlusal contact on electromyographic activity, unaffected by pain and functional disorders. Occlusal stability was assessed in the intercuspal and in lateral contact positions as the number of teeth with physical contact and the number of opposing pairs of teeth in contact. Electromyographic activity was recorded by surface electrodes over anterior and posterior temporalis and masseter muscles. In general, positive correlations were found between occlusal stability in intercuspal position and moderate to strong static and dynamic contractions, most significant in masseter muscles, indicating that forceful contraction of these muscles implies stable occlusion. Systematically, the duration of activity during chewing was negatively correlated with occlusal stability in the intercuspal position, most pronounced in working-side muscles. This pointed to shorter contractions with stable occlusion and is interpreted as the result of less need for stabilizing activity. It is concluded, that the correlations between occlusal stability and elevator muscle function are probably based on feedback mechanisms from periodontal pressoreceptors.     

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提要：牙齿松动是牙周病主要的临床症状之一。如何治疗松动牙、防止牙周炎进行性加重、尽可能地保存牙齿、促进牙周组织的重建再生,是牙周科医生致力于解决的主要问题。经牙周基础治疗、去除危险因素、消除牙周组织炎症并建立平衡牙合后,多数患牙的松动度可不同程度减轻。而松动度较大的患牙经牙周治疗也很难恢复正常,并影响咀嚼功能,产生继发性牙合创伤,使得牙周组织破坏、吸收加剧。对动度较大的松动牙进行固定,消除其创伤,减轻牙合力负担,使之行使正常咬合功能,牙周膜接受功能性刺激,从而促进牙周组织的修复和愈合。因此,松牙固定是牙周治疗的必要措施。牙周炎的松牙固定是将单根或多根患牙与健康牙通过夹板连接成一个稳固的“多根牙”,建立起一个新的咀嚼单位。本文对牙周病的松动牙固定、各类牙周夹板在临床上的使用及夹板固定技术做一介绍。     

A clinical study of the functional significance of the occlusal contacts on chewing movements

The study was aimed to investigate the effects of the occlusal contacts on chewing movements according to the changes of the mandibular first molar crown surfaces in 32 young adults. The study includes three components of the experiments as the control, various types of occlusal contact defects and the excessive conditions of occlusal surface contacts on the tooth. The chewing movement consistency was tested in the control study. The effects of the occlusal contact defects to the chewing movements, i.e., a periodontal mechanoreceptive defect (sensory block), a complete defect of coronal contact, partial defects (buccal or lingual cusp and inclination) of coronal surface, were then examined. Third, the effects of the occlusal deflective interference provided for the subjected tooth to the chewing movement was examined as the experiment in the excessive condition. The results obtained were as follows: 1. The consistency of segmental single tooth chewing movements was tested in the control study and revealed highly reliable among parameters of intra-day variance, but not enough for the inter-day variance in each subject. 2. The effects of occlusal contact defects were significant to the path and the rhythm of chewing movements in a poriodontal mechanoreceptive defect, complete coronal defect, cusp and inclination defects. 3. The effects of deflective occlusal interference were significant in the parameters, such as posterior deviation during closing path and inferior deviation of occluding point, prolonged duration in the closing phase, and shortening of duration in the occluding phase. It is suggested that either the occlusal defects or the interference conditions on one side of the first mandibular molar tooth may provide some effects to the chewing movements, and that appropriate occlusal contacts for the tooth may serve to maintain stabilized the path and the rhythm during chewing movements.     

Clinical Study on the Analysis of Chewing Movements in Relation to Occlusion

The purpose of this study was to examine how the occlusal factor influences the chewing movement. The subjects were divided into two groups; one consisted of 10 subjects whose chewing patterns look like grinding movements, which we named “grinding type,” and another consisted of 15 subjects whose chewing patterns look like chopping movements, which we named “chopping type.” The distance of separation between the lower functional cusp tips and the upper teeth in centric occlusion and at lateral mandibular position was measured and analyzed in the two groups. In centric occlusion, the distancewas less in the chopping type than in the grinding type. On the contrary, at lateral mandibular position, the distance was less in the grinding type.

This study suggests that the chewing pattern has some relationship to occlusion, especially to the distance between the upper and the lower posterior teeth in the lateral mandibular position.     

Occlusal contact area of mandibular teeth during lateral excursion

PURPOSE: This study observed occlusal contacts and determined their areas on the mandibular teeth, especially the molars, during voluntary lateral excursions. MATERIALS AND METHODS: Occlusal contact areas were estimated with a measurement system combining 3-D tracking of mandibular movements with 3-D digitization of tooth shape. Sixteen women with sound permanent dentitions participated. RESULTS: At the intercuspal position, estimated occlusal contact areas of the first and second mandibular molars were on average 12.6 mm2 and 9.0 mm2, respectively. However, after 3.0 mm of lateral excursion, their areas were sharply reduced to 2.2 mm2 and 1.5 mm2 on the working side, and 0.4 mm2 and 1.1 mm2 on the nonworking side, respectively. CONCLUSION: These results suggest that the occlusal contact areas on working- and nonworking-side molars differ from each other as lateral excursion proceeds.     

Relationship between occlusal tooth contact patterns and tightness of proximal tooth contact

summary   The aim of this study was to investigate the relationship between occlusal tooth contact patterns and the tightness of proximal tooth contact (TPTC) during clenching. Twenty young adult volunteers with healthy dentition participated in the study. TPTC between the left second premolar (P2) and the first molar (M1) was measured during clenching at the 50% maximum voluntary contraction level in the intercuspal position (ICP). A silicone impression material was used to make an interocclusal record at the ICP in each subject, and interocclusal records were analysed using an image-processing system. Subjects were classified according to the presence or absence of each type (A, B or C) of occlusal contact. Statistical analysis was performed using the Mann–Whitney U -test. The results of this study exhibited a relationship between B-type contact and the TPTC of maxillary teeth. The experimental group with a lack of B-type contact on maxillary P2 and/or M1 showed a statistically greater TPTC than the group with B-type contact on both of these teeth ( P  < 0·01). These results suggest that occlusal tooth contact patterns have an influence on TPTC during clenching.     

A retrospective analysis of factors associated with the periapical status of restored,endodontically treated teeth

PURPOSE: The purpose of this study was to explore possible associations between prosthodontic, occlusal, endodontic, and periodontal factors and the endodontic status of endodontically treated teeth. MATERIALS AND METHODS: Forty-six patients who had received endodontic treatment followed by a fixed restoration for at least one of their teeth were recalled and examined clinically and radiographically according to a predetermined set of evaluation criteria. A total of 89 teeth were included, and data obtained included assessments of the coronal restoration and post and core, occlusal contact relationships, a number of endodontic parameters, and periodontal status of the study teeth. For the latter assessment, 54 contralateral teeth were available for purposes of comparison. Teeth were grouped into those with and without periapical radiolucencies, and differences between the groups, with respect to all parameters, were analyzed by logistic regression. RESULTS: Three factors were significantly associated with the presence of radiolucency: confirmed occlusal contact, by virtue of the tooth being either involved in group function or the only contact in working-side and protrusive movements, and endodontic filling and crown margins of poor quality. None of the other independent variables showed significant associations with the dependent variable of periapical radiographic appearance. Contralateral teeth had better periodontal conditions than restored study teeth. CONCLUSION: The finding that a good-quality endodontic filling and crown margin improve endodontic outcome corroborates many other similar reports; however, with occlusal contact shown to be associated with failing endodontic treatment, the range of factors that may influence endodontic outcome appears to have widened.     

Correlation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of therapy

Aim: The association between periodontal status and biting force is unclear. The aim of this study was to investigate the relation between periodontal status and biting force in patients with chronic periodontitis during the maintenance phase of periodontal treatment. Material and Methods: A total of 198 patients, who had entered a periodontal maintenance programme, were examined for the presence of restorations on the occlusal surface, probing pocket depth, clinical attachment loss (CAL), bleeding on probing, and mobility of teeth. Quantitative analysis of total biting force, occlusal contact area and biting pressure (defined by biting force per 1 mm² of occlusal contact area) was performed using microcapsular pressure‐sensitive sheets. Results: A multiple stepwise regression analysis showed that total biting force and occlusal contact area were positively associated with the number of present teeth and negatively associated with female gender, mean CAL and mean probing pocket depth. Biting pressure was positively associated with CAL. Conclusions: Reduced periodontal support was found to be associated with decreased total biting force and with increased biting pressure (defined as force per 1 mm² of occlusal contact area).     

Association of periodontal status with occlusal force and food acceptability in 70‐year‐old adults: from SONIC Study

This cross‐sectional study aimed to investigate the association of periodontal status with occlusal force and food acceptability. We hypothesised that mastication deteriorated with reduced periodontal support, even when posterior occlusal contacts with natural teeth were maintained and the patients remained clinically asymptomatic. Participants were 482 independently living 69‐71‐year‐olds, classified as Eichner's group A, having no mobile teeth and no periodontal symptoms. The periodontal probing depth (PPD) and restoration status of each tooth were examined. Occlusal force in the intercuspal position was measured with pressure‐sensitive films. Food acceptability was evaluated from the difficulty experienced in chewing apples, grilled beef, and hard rice crackers. Multivariate regression analysis was performed to investigate the association of periodontal status with occlusal force and food acceptability. A P‐value of <0·05 was considered statistically significant. Multiple linear regression analysis showed that occlusal force had significant negative associations with maximal PPD (standardised partial regression coefficient (β) = ?0·121) after controlling for gender, handgrip strength, number of teeth, and percentage of restored teeth. Approximately 15% of participants were included in the compromised food acceptability group. Logistic regression analyses showed that compromised food acceptability was significantly associated with PPD, after controlling for gender, number of teeth, and percentage of restored teeth. Periodontal probing depth (PPD) was significantly correlated with occlusal force and self‐rated food acceptability after controlling for the possible confounding factors in septuagenarians, even those with complete posterior occlusal contacts and no tooth mobility.     

Masticatory jaw movement optimization after introduction of occlusal interference

Summary How ‘control’ characteristics of masticatory jaw movement, such as skilfulness of the movement, change after alteration in occlusion remains uncertain. For each of 10 healthy adults with good occlusion, an occlusal interference with artificial ‘tooth‐cusp’ was introduced to the crown of the upper molar tooth on the non‐working side of unilateral chewing. Mandibular incisor‐point movements were then recorded by a 3D tracking device. The introduction of the occlusal interference induced a remarkable increase in the normalized jerk‐cost (NJC), prolonged duration of the decelerative phase and lowered peak velocity for jaw closing movement during chewing. Overall, the NJC and velocity profile showed significant recoveries during the course of about 90 repetitive chewing cycles performed under the altered occlusal condition. These findings suggest that acute adaptive changes of jaw motion after introduction of occlusal interference might be characterized as the recovery process of movement skilfulness in terms of movement smoothness and velocity profile.     

Relationship between the prognosis of periodontitis and occlusal force during the maintenance phase – a cohort study

Takeuchi N, Ekuni D, Yamamoto T, Morita M. Relationship between the prognosis of periodontitis and occlusal force during the maintenance phase – a cohort study. J Periodont Res 2010; 45: 612–617. © 2010 John Wiley & Sons A/S Background and Objective: Few studies have longitudinally investigated the relationship between periodontal disease progression and occlusal factors in individual subjects during the maintenance phase of periodontal therapy. The aim of this cohort study was to investigate the relationship between biting ability and the progression of periodontal disease in the maintenance phase. Material and Methods: A total of 194 patients were monitored for 3 years during the maintenance phase of periodontal therapy. The subjects with disease progression (Progress group) were defined based on the presence of ≥ 2 teeth demonstrating a longitudinal loss of proximal attachment of ≥ 3 mm or tooth‐loss experience as a result of periodontal disease during the study period. The subjects with high occlusal force were diagnosed as men who showed an occlusal force of more than 500 N and women who showed an occlusal force of more than 370 N. The association between biting ability and the progression of periodontitis was investigated using logistic regression analysis. Results: There were 83 subjects in the Progress group and 111 subjects in the Non‐progress group. A backward, stepwise logistic regression model showed that the progression of periodontal disease was significantly associated with the presence of one or more teeth with a high clinical attachment level (CAL) of ≥ 7 mm (odds ratio: 2.397; 95% confidence interval: 1.306–4.399) ( p = 0.005) and low occlusal force (odds ratio: 2.352; 95% confidence interval: 1.273–4.346) ( p = 0.006). Conclusion: The presence of one or more teeth with a high CAL of ≥ 7 mm and low occlusal force might be possible risk factors for periodontal progression in the maintenance phase of periodontal therapy.     

When homologous cusps display non-homologous wear facets: An occlusal reorganization ensures functional continuity during dental evolution of Murinae (Rodentia, Mammalia)

Objective

This study was designed to interpret the differences between the occlusal relationships in the murine rodents and those in their Miocene “cricetodont” ancestors. It aimed at understanding the functional transformations that led to the emergence of the peculiar chewing motion of the Murinae, associating forwardly directed masticatory movements to cusp interlocking, a trait unique amongst mammals.

Methods

Microwear analyses and simulations of occlusion achieved with size-increased 3D printings of teeth crafted from 3D data obtained by X-ray synchrotron microtomography at the European synchrotron radiation facility allow us to carefully interpret the occlusal relationships in Muroidea.

Results

A rotation of the direction of the chewing movements occurred from “Cricetodontinae” to Murinae. This rotation emerged without any cusp removal contrary to previous interpretations, by the way of an occlusal reorganization involving a loss of contacts between some cusps, offset by a contact with other cusps. This new organization was already present in the early and middle Miocene genus Potwarmus.

Conclusion

Molar tooth evolution in Murinae was characterized by the preservation and the reshaping of the primitive muroid cusps, the acquisition of supplementary cusps, and changes in the contacts between the opposite cusps. During evolution, changes of cusp patterns in upper and lower molar teeth are coordinated in order to retain a functional occlusion. Because of this functional constraint, one cusp was supposed to more likely occlude with the same opposite cusps during evolution, and therefore homologous cusps would always carry homologous attrition facets. Evolution of Murinae proves that functional continuity can also be preserved through changes in occlusal relationships independently from cusp removal.     

A review of the clinical management of mobile teeth

The clinical management of mobile teeth can be a perplexing problem, especially if the underlying causes for that mobility have not been properly diagnosed. In some cases, mobile teeth are retained because patients decline multidisciplinary treatment that might otherwise include strategic extractions. This article discusses the relationship between occlusion and tooth mobility with an emphasis on identifying differences between increased mobility and increasing mobility. The indications, contraindications, and basic principles of tooth splinting are also reviewed. Provisional and definitive splints are defined and described with their respective occlusal considerations. Some mobile teeth can be treated through occlusal equilibration alone (primary occlusal trauma). Whereas mobile teeth with a compromised periodontium can be stabilized with the aid of provisional and/or definitive splinting (secondary occlusal trauma). It is important to consider splint therapy, because it may not only improve the prognosis of teeth, but may actually enhance the stability of the final prosthodontic treatment. The ultimate goal of successful management of mobile teeth is to restore function and comfort by establishing a stable occlusion that promotes tooth retention and the maintenance of periodontal health.