Does overbite reduction affect smile esthetics?

Objectives:To compare the effects of two common methods of overbite reduction on smile esthetics.Materials and Methods:A prospective clinical trial was conducted with 32 patients in whom overbite reduction was achieved using a maxillary incisor intrusion arch (18 patients) or flat anterior bite plate (14 patients). Clinical and cephalometric records were compared pretreatment (T1), after overbite reduction (T2), and posttreatment (T3).Results:Both treatment groups experienced a reduction in overbite and maxillary and mandibular incisor proclination during treatment (T1–T3). The center of resistance of the maxillary incisor and the incisal edge was significantly intruded in the intrusion arch group during overbite reduction (T1–T2). However, most of the intrusion of the center of resistance was lost by the end of treatment (T2–T3). Both treatment groups experienced a reduction in maxillary incisor display and flattening of the smile arc during overbite reduction.Conclusions:Both overbite reduction methods caused a decrease in incisor display and flattening of the smile arc. Smiles were improved in some patients by the end of treatment. However, reduction in incisor display persisted. Clinicians should take precautions to prevent negative effects of overbite reduction.     

Does oral health affect self perceptions,parental ratings and video‐based assessments of children's smiles?

OBJECTIVES: To explore whether there is a relationship between children's objectively determined oral health status and their oral health-related quality of life, specifically the evaluations of their smiles as assessed by the children, their parents, and through measurements of the children's videotaped smiles. METHODS: Chart review data were collected from 99 children (56 boys, 43 girls; average age: 7.06 years; range: 4-12 years) to determine their oral health status. The children responded to the Michigan Oral Health-Related Quality of Life Scale - Child Version (MOHRQOL-C), and the parents responded to the Michigan Oral Health-Related Quality of Life Scale - Parent Version (MOHRQOL-P) to assess the smiling-related aspect of the children's oral health-related quality of life. Parents also responded to questions concerning their own evaluations of their child's smile. The children were videotaped while they watched a funny cartoon. Two independent raters measured the width and openness of the children's mouth plus the number of teeth shown at 25 predetermined time points during these taped sessions to assess the children's video-based smiling patterns. RESULTS: The children's self evaluated smile scores correlated with the video-based ratings of the children's smiles, and with the number of positive adjectives parents chose to describe their children's smiles. There were significant relationships between several indicators of oral health status and all smile assessment scores. Children without caries evaluated their own smiles more positively, showed more teeth when smiling, and received more positive parent evaluations for their smiles than children with decay. CONCLUSION: Poor oral health is significantly related to children's smiling patterns and the way others perceived their smiles. Poor oral health may prevent children from expressing positive emotions, which can impact their social interactions and the way they feel about themselves.     

Could medications and biologic factors affect post-orthodontic tooth movement changes? A systematic review of animal studies

Immediately after the removal of orthodontic appliances, the teeth might start to drift away from their corrected position in an attempt to reach a new equilibrium. Medications and biologic factors could potentially modulate these processes. The objective of the present systematic review is to systematically investigate and appraise the quality of the evidence regarding the effect of various medications and biologic factors on the rate of relapse following active tooth movement. Search without restrictions in eight databases and hand searching until April 2020 were conducted. Studies performed on animal models investigating the effects of medication and biologic factors on the rate of relapse following orthodontic tooth movement were considered. Following study retrieval and selection, relevant data were extracted and the risk of bias was assessed. Seventeen studies were finally identified, mostly at either high or unclear risk of bias. Ketorolac did not show any significant effects on relapse, while the administration of tetracycline, atorvastatin, psoralen and raloxifene decreased it. Overall, the same result was observed with bisphosphonates with the exception of low dosage of risedronate, which did not have an effect. Osteoprotegerin and strontium resulted in reduced relapse, but not in the immediate post-administration period. Inconsistent or conflicting effects were noted after the use of simvastatin and relaxin. The quality of the available evidence was considered at best as low. It can be concluded that specific medications and biologic factors may have an effect on the rate of relapse following tooth movement. The orthodontist should be knowledgeable about the substances potentially affecting retention.     

How do age and tooth loss affect oral health impacts and quality of life? A study comparing two national samples

Age and loss of teeth can be expected to have a complex relationship with oral health-related quality of life. This study aimed to explain how age and tooth loss affect the impact of oral health on daily living using the short form, 14-item Oral Health Impact Profile (OHIP-14) on national population samples of dentate adults from the UK (1998 UK Adult Dental Health Survey) and Australia (1999 National Dental Telephone Interview Survey). After correcting for key covariables, increasing age was associated with better mean impact scores in both populations. Those aged 30-49 years in Australia showed the worst (highest) scores. In the UK, those aged under 30 showed the highest scores. In both countries, adults aged 70+ showed much better scores than the rest (P < 0.001). When corrected for age, the independent effect of tooth loss was that the worst scores were found where there were fewer than 17 natural teeth in the UK and fewer than 21 teeth in Australia. People with 25 or more teeth averaged much better scores than all other groups (P < 0.001), although there were differences in pattern between countries. When Australians were analysed by region of birth, the pattern of scores by tooth loss for British/Irish immigrants was strikingly similar to that for the UK sample. First-generation immigrants from elsewhere showed much worse overall scores and a profoundly different pattern to the Australian- and British-born groups. Age, number of teeth and cultural background are important variables influencing oral health-related quality of life.     

Changes in tooth mortality between 1990 and 2002 among adults in Västerbotten County, Sweden: influence of socioeconomic factors, general health, smoking, and dental care habits on tooth mortality

The objectives of the study were to analyse changes in tooth mortality among adults in V?sterbotten County, Sweden, between 1990 and 2002 and determine whether socioeconomic factors, general health, smoking, and dental care habits influenced tooth mortality. The study was based on samples drawn from the adult population in V?sterbotten County in 1990 and 2002. The studied age groups were 35-, 50-, and 65-year-olds. In 2002 75-year-olds were included. The surveys comprised a clinical examination and a questionnaire.The latter focused on oro-facial symptoms, socioeconomic factors, general health, smoking, and dental care habits. Complete data were obtained from 715 individuals in 1990 and from 768 individuals in 2002.Variables used to depict tooth mortality were edentulousness, occlusal supporting zones (Eichner index), and number of teeth. The prevalence of edentulousness in V?sterbotten County decreased from 12.7% in 1990 to 3.7% in 2002 (P < 0.001). The mean number of teeth increased in all age groups between 1990 and 2002, and so did the number of individuals with tooth contact in all occlusal supporting zones and no gaps between teeth. Low educational level, weak economic status, smoking, and irregular visits to the dental clinic were all significantly related to increased tooth mortality. Between 1990 and 2002 tooth mortality decreased significantly in the adult population of V?sterbotten County, Sweden. Cross-sectional analysis identified socioeconomic factors, smoking, and irregular use of dental care services as being related to tooth mortality in both 1990 and 2002.     

What Do Older Adults' Global Self‐ratings of Oral Health Measure?

OBJECTIVE: Although global self-ratings of oral health are widely used in oral health research, the frames of reference on which older people's ratings are based are not known. This study used a quantitative approach in order to identify these referents. METHODS: Data were collected from 498 dentate subjects aged 53 years and over who took part in the second stage of a three-phase longitudinal epidemiological and sociodental study. Data were obtained by means of a personal interview and clinical oral examination and a self-complete version of the 49-item Oral Health Impact Profile (OHIP). These data were used to construct measures of oral disorders, oral symptoms, the functional and psychosocial impacts of oral disorders, health behaviours and contextual variables such as general health status, socioeconomic status and sociodemographic characteristics. Bivariate and linear regression analyses were used to identify which of these variables predicted self-ratings of oral health. RESULTS: One quarter of subjects stated that their oral health was only fair or poor. At the bivariate level most variables were associated with self-ratings of oral health. The regression model for all subjects indicated that the most important predictor of these self-ratings was the OHIP functional limitations sub-scale score. This explained 23% of the variation in the self-ratings. Six other variables entered the model and increased the R2 value to 0.36. There was some variation in the models and the influence of various factors by age and educational attainment. CONCLUSIONS: The results suggest that the referents that inform older adults' ratings of oral health are broadly similar to those that have been reported to inform their ratings of general health and differ across groups.     

Does the floor of the maxillary sinus affect tooth movement for premolar extraction space closure?

Objective

The study investigated orthodontic tooth movement by comparing various horizontal and angular measures of the teeth having different sinus–root relationship (SRR) of patients undergoing first premolar extraction treatment protocols.

Materials and methods

This retrospective cross-sectional study included 45 Taiwanese adult patients, classified as the control group (n?=?15) and the sinus group (n?=?30) according to SRR. The control group had type I SRR (sinus floor above the level connecting the buccal and palatal root apices), whereas the sinus group included patients with type V SRR (the buccal and palatal root displayed apical protrusion into the sinus floor). Morphology was identified using pretreatment orthopantomograms. Lateral cephalometric measurements were conducted before treatment (T1) and at debonding (T2).

Results

Post debonding, there were no statistically significant difference in the two groups. However, the incisors in the control group became marginally more upright than those of the sinus group, and the molars demonstrated tipping movement with minimal anchorage loss in the sinus group than in the control group. The total treatment time was not significantly different between the 2 groups.

Conclusion

The study revealed that the sinus–root relationship does not affect the orthodontic tooth movement. However, a more extensive 3-D study with larger sample size is strongly recommended before coming to any conclusion.

Clinical relevance

The lining of the floor of the maxillary sinus does not affect the orthodontic tooth movement.

     

Do tooth gaps matter? Evaluation of self‐assessments: a pilot study

This study aimed to test the hypothesis stating no difference in number of teeth or tooth gaps counted by the dentist or the patient. The sample consisted of 49 randomly selected regular patients and their dentists (response rate 10%, 53% males). Mean age of the patients was 53.6 +/- 11.9 years. The mean number of teeth was 26.5, 20/49 reported tooth gaps (excluding second and third molars) and 12/20 had visible gaps. The calculation of patients' detection of gaps showed a sensitivity = 79%, specificity = 96% and a positive predictive value of 95%. The patients reported more teeth in the maxilla and fewer teeth in the mandible compared with their dentists. More teeth were misdiagnosed as the number of teeth increased in the mandible. Patients reported more gaps than dentists in both jaws (NS); an average of 0.04, 0.18 and 0.22 misdiagnosed gaps in the maxilla, mandible and for both jaws respectively. Agreement on tooth present/missing in the maxilla was 91.3% (+/-9.82) and in the mandible 88.2% (+/-10.44). Correlation between self-report and dentist's report of the number of teeth present and the number of gaps in the maxilla was (Pearson's r) 0.94 and 0.83. One person with self-perceived visible gaps and five persons with non-visible gaps were recommended treatment; two persons agreed about a treatment need. Self-assessments of tooth gaps show limited but acceptable sensitivity and excellent specificity. No significant differences in tooth counting were found when comparing self-reports and dentists' reports. The study should be tried on a larger scale.     

Does the transition temperature of Cu–NiTi archwires affect the amount of tooth movement during alignment?

OBJECTIVES: To examine whether the transition temperature of Cu-NiTi archwires has an effect on the tooth movement during the alignment phase of orthodontic treatment. DESIGN: 'Split mouth' design in randomly selected patients. SETTING AND SAMPLE POPULATION: The Department of Orthodontics, School of Dentistry, University of Aarhus. Fifteen randomly selected patients with identical level of irregularity in the alignment phase of their treatment. Experiment Variable - Specially manufactured Cu-NiTi archwires for the upper arch were inserted. These consisted of two separate halves, each with its own transition temperature, respectively 27 degrees and 40 degrees C, and clamped together in the middle. OUTCOME MEASURE: The tooth movement, expressed as two translations and a rotation, in the occlusal plane was measured from the patients' intraoral photographs taken upon insertion of the archwires and again after 1 month. RESULTS: Tooth movements tended to be larger on the 40 degrees C-side, however only in case of the total translation of the premolars was this difference significant. In general, patients had not noticed any difference between the two sides of the archwire, although one patient stated the 27 degrees C-side to be more comfortable as the 40 degrees C-side had bothered her when drinking hot beverages. CONCLUSION: The transition temperature of Cu-NiTi archwires has indeed an effect on the amount of tooth movement during alignment. However, the differences are so small though that it is the question whether they can be noticed clinically. The study corroborates the trend towards the use of lower forces within orthodontics.     

Natural mediotrusive contact: does it affect the masticatory and neck EMG activity during tooth grinding?

Objectives: There is scarce knowledge regarding the influence of a natural mediotrusive contact on mandibular and cervical muscular activity. The purpose of this study was to analyze the EMG activity of the anterior temporalis (AT) and sternocleidomastoid (SCM) muscles during awake grinding in healthy subjects with or without a natural mediotrusive occlusal contact.

Method: Fifteen subjects with natural mediotrusive occlusal contact (Group 1) and 15 subjects without natural mediotrusive occlusal contact (Group 2) participated. Bilateral surface EMG activity of AT and SCM muscles was recorded during unilateral eccentric or concentric tooth grinding tasks. EMG activity was normalized against the activity recorded during maximal voluntary clenching in intercuspal position (IP) for AT muscles and during maximal intentional isometric head-neck rotation to each side, for SCM muscles.

Results: EMG activity of AT and SCM muscles showed no statistical difference between groups. EMG activity of AT muscle was higher in the working side (WS) than in the non-WS (NWS) in Group 1 during concentric grinding (0.492 vs 0.331, p?=?0.047), whereas no difference was observed in Group 2. EMG activity of SCM was similar between working and NWSs in both groups and tasks. Asymmetry indexes (AIs) were not significantly different between groups.

Discussion: These findings in healthy subjects support the assumption that during awake tooth grinding, central nerve control predominates over peripheral inputs, and reinforce the idea of a functional link between the motor-neuron pools that control jaw and neck muscles.     

Do blood contamination and haemostatic agents affect microtensile bond strength of dual cured resin cement to dentin?

Objective:

The purpose of this study was to evaluate the effects of blood contamination and haemostatic agents such as Ankaferd Blood Stopper (ABS) and hydrogen peroxide (H₂O₂) on the microtensile bond strength between dual cured resin cement-dentin interface.

Material and Methods:

Twelve pressed lithium disilicate glass ceramics were luted to flat occlusal dentin surfaces with Panavia F under the following conditions: Control Group: no contamination, Group Blood: blood contamination, Group ABS: ABS contamination Group H₂O₂: H₂O₂ contamination. The specimens were sectioned to the beams and microtensile testing was carried out. Failure modes were classified under stereomicroscope. Two specimens were randomly selected from each group, and SEM analyses were performed.

Results:

There were significant differences in microtensile bond strengths (µTBS) between the control and blood-contaminated groups (p<0.05), whereas there were no significant differences found between the control and the other groups (p>0.05).

Conclusions:

Contamination by blood of dentin surface prior to bonding reduced the bond strength between resin cement and the dentin. Ankaferd Blood Stoper and H₂O₂ could be used safely as blood stopping agents during cementation of all-ceramics to dentin to prevent bond failure due to blood contamination.     

Do periapical and periodontal pathologies affect Schneiderian membrane appearance? Systematic review of studies using cone-beam computed tomography

Clinical Oral Investigations - This systematic review analyzed the relationship between periapical and periodontal pathologies in the posterior maxilla and the appearance of the Schneiderian...     

Should retention of a tooth be an important goal of dentistry? How do you decide whether to retain and restore a tooth requiring endodontic treatment or to extract and if possible replace the tooth?

Whether a questionable tooth should be treated endodontically or extracted, is still a dilemma clinicians encounter every day. With advances in technology such as implantology, deciding whether or not to save a tooth is still not clear. Local site‐specific factors and patient‐related factors that may affect the longevity of a particular tooth should be considered in preparing the treatment plan. Long‐term success rates for root canal therapy and implant‐supported crowns demonstrate similar outcomes. A choice between these alone is not sufficient in the decision‐making process. Only following a systematic evaluation of the reasons for and against tooth retention as directed by each individual case, can the best option be decided.