Relationship between alignment conditions of teeth in anterior segments and incisal wear

The consequences of living with a severe malocclusion: A review of the literature

AIM

To facilitate the orthognathic shared decision-making process by identifying and applying existing research evidence to establish the potential consequences of living with a severe malocclusion.

METHODS

A comprehensive narrative literature review was conducted to explore the potential complications of severe malocclusion. A systematic electronic literature search of four databases combined with supplementary hand searching identified 1024 articles of interest. A total of 799 articles were included in the narrative literature review, which was divided into 10 themes: Oral Health Related Quality Of Life; Temporomandibular Joint Dysfunction; Masticatory Limitation; Sleep Apnoea; Traumatic Dental Injury; Tooth Surface Loss; Change Over Time; Periodontal Injury; Restorative Difficulty; and Functional Shift and Dual Bite. A deductive approach was used to draw conclusions from the evidence available within each theme.

RESULTS

The narrative literature review established 27 conclusions, indicating that those living with a severe malocclusion may be predisposed to a range of potential consequences. With the exception of Oral Health Related Quality Of Life, which is poorer in adults with severe malocclusion than those with normal occlusions, and the risk of Traumatic Dental Injury, which increases when the overjet is >5 mm in the permanent and 3 mm in the primary dentition, the evidence supporting the remaining conclusions was found to be of low to moderate quality and at high risk of bias.

CONCLUSION

This article summarises the findings of a comprehensive narrative literature review in which all of the relevant research evidence within a substantive investigative area is established and evaluated. Notwithstanding limitations regarding the quality of the available evidence; when combined with clinical expertise and an awareness of individual patient preferences, the conclusions presented may facilitate the orthognathic shared decision-making process and furthermore, may guide the development of the high-quality longitudinal research required to validate them.

Tooth wear patterns in subjects with class II division 1 and class II division 2 malocclusion

INTRODUCTION

There is an increasing trend of malocclusion among children, so it is necessary to identify the cause of the tooth wear so that the orthodontist can treat the patient accordingly. It is necessary to determine the wear patterns of different malocclusions. Therefore, the aim of our study was to compare the patterns of tooth wear among two categories of Angle's class II malocclusions, i.e. class II division 1 and class II division 2.

MATERIAL AND METHODS

The sample consisted of 100 pretreatment orthodontic patients in the age group of 15-25 years with Angle's class II malocclusion and were divided into following two groups: (a) Group 1: 50 subjects with full cusp Angle's class II division 1 malocclusion. (b) Group 2: 50 subjects with full cusp Angle's class II division 2 malocclusion. Clinical examination of the patients for tooth wear was done supplemented with dental casts, intraoral photographs and intraoral radiographs. Then each group was assessed for severity of tooth wear according to modified tooth wear index (TWI) given by de Carvalo Sales-Peres et al. Scores were subjected to statistical analysis and the pattern of tooth wear among the two groups of class II malocclusion was compared. A correlation between the gender of the patient and the tooth wear was also determined. The level of statistical significance (p-value) was less than 0.05.

RESULTS

The class II division 1 subjects showed statistically greater wear on the occlusal surfaces of the maxillary canines, first, second premolar and first molar, and the occlusal surfaces of the mandibular first molars. The class II division 2 subjects showed statistically greater tooth wear on the labial surfaces of the mandibular central and lateral incisors, the incisal surface of maxillary and mandibular incisors, the palatal surfaces of the maxillary second premolars, first and second molars. In class II division 1 subjects, the tooth wear was significant on the buccal surface of maxillary canines, occlusal surface of mandibular first premolars and second molars in males. In class II division 2 subjects, the tooth wear was significant on the buccal surface of mandibular canines, palatal surface of maxillary central incisors in females and palatal surface of maxillary first premolars in males.

CONCLUSIONS

The results of this study suggested that the two categories of Angle's class II malocclusion have different tooth-wear patterns. The wear patterns were different in both the sexes. Men showed higher occlusal wear scores than did women. The findings also suggest that tooth wear in relation to malocclusion is physiologic and is due to dissimilar interocclusal arrangement.

Tooth wear during orthodontic treatment with fixed appliances: a systematic review

OBJECTIVES

Tooth wear, additional to the physiologic alterations of the dentition, may occur during orthodontic treatment. The objective of the present review was to investigate systematically the literature relevant to its progression in patients having undergone comprehensive orthodontic treatment.

DATA SOURCES

Search without restrictions in eight databases since inception and hand searching until October 2017 was performed.

DATA SELECTION

Studies evaluating tooth wear immediately before and after the completion of orthodontic treatment with fixed appliance were evaluated independently and in duplicate.

DATA EXTRACTION

Following study retrieval and selection, data on volumetric and surface tooth wear was extracted. Individual study risk of bias assessment was performed using the Risk Of Bias In Non-randomised Studies - of Interventions (ROBINS-I) tool, and the overall quality of the evidence was assessed with the Grades of Recommendation, Assessment, Development and Evaluation approach.

DATA SYNTHESIS

All three finally included studies reported wear of teeth during the period of treatment but were at serious risk of bias. Two of them investigated tooth wear by 3D volumetric measurements and one used grading scales. The mean volume reduction was 1.02 mm³ per tooth for the incisor group [95% Confidence Interval (CI): 0.84-1.20], 1.62 mm³ for the canines [95% CI: 0.8-2.38; I²= 96%; random effects method] and 0.95 mm³ for premolars and molars [95% CI: 0.84-1.07]. The overall quality of evidence limited the confidence in the observed estimates.

CONCLUSIONS

Varying degrees of tooth wear were reported after comprehensive orthodontic treatment. Further studies are needed in order to elucidate how much is associated with orthodontic treatment and/or physiologic alterations of the dentition.

A review of the oral health-related evidence that supports the orthodontic treatment need indices

BACKGROUND AND OBJECTIVES

To date, there is no evidence-based method of quantification for malocclusion. Consequently, how deviant occlusal traits should be scored and weighted relative to one another is a matter of serious debate. Orthodontic Treatment Need Indices (OTNI) use the subjective opinion of the experts, as their foundation, to define the pathological boundaries (cut-offs) of occlusal traits. This paper reviews the evidence relating malocclusions or deviated occlusal traits to oral health problems, and investigates if this evidence supports the cut-off points and the rationale used for OTNI.

MATERIALS AND METHODS

The relevant cited studies and reviews from the MEDLINE, Web of Science, Scopus, Cochrane databases, and scientific textbooks were used. The citation rate was confirmed by using the Google Scholar.

RESULTS

So far, the evidence for harmful effects of deviated occlusal traits on oral health is either lacking or exists as cross-sectional (mostly) and longitudinal (a few and primarily short-term) studies. When an association was reported between a deviated occlusal trait and an oral health problem, either the strength of that association was weak, or due to methodological issues, findings were not conclusive. Consequently, establishing a cause and effect relationship is difficult. Further, commonly used OTNI do not record a full spectrum of occlusal traits, and relating their ranking or scoring systems to the available evidence is difficult. Therefore, there is little evidence to suggest that individuals with a high need (high score), as measured by OTNI, will necessarily put at risk their oral health if they turn down orthodontic therapy.

CONCLUSION

OTNI have a role in the epidemiology and can be used for resource planning, but their predictive value to detect the future objective functional deficits or oral health problems is questionable. OTNI will need revalidation over time with emerging research findings.

Anterior tooth wear and retention type until 5 years after orthodontic treatment

OBJECTIVES

To study occlusal wear of anterior teeth in orthodontic patients retained with different retainers until 5 years post-treatment, and to investigate whether type of retention influences occlusal wear.

MATERIAL AND METHODS

Orthodontic patients (n=222), aged 15 years maximally at the start of treatment, were followed until 5 years post-treatment. In the maxilla, a retainer bonded on all six teeth or a removable retainer was used; in the mandible, a lingual retainer was bonded on all anterior teeth or on canines only. Dental casts were analyzed before treatment (T(0)), after treatment (T(1)), and 5 years post-treatment (T(5)). Incisal and canine wear were scored by applying a grading scale. Intercanine width, overjet, and overbite were measured with an electronic caliper. Statistics used were: Paired samples t-test for differences over time; Pearson correlation coefficients for associations between wear and retention type; and backward linear regression for influence of retention type on wear.

RESULTS

There was an increase in wear during all time periods and for all teeth. From T(0) to T(5) an increase in maxillary intercanine width and maxillary retention had an effect on changes in canine wear. Incisal wear was associated with an increase in upper intercanine width (T(1)-T(5)). For both arches, an increase in maxillary intercanine width during treatment was associated with less progression of canine and incisal wear, but the explained variance was low, 13.4% and 19.3%, respectively.

CONCLUSIONS

Retention type and, occasionally, an increase in intercanine width influence anterior teeth wear post-treatment. However, the clinical significance and impact of the examined retention methods on occlusal wear are small.