Minimally important differences in oral health-related quality of life after fixed orthodontic treatment: a prospective cohort study.

BACKGROUND: The minimally important difference (MID, the smallest difference that patients perceive as beneficial) has been proposed to assess whether study results are clinically meaningful, reducing the shortcoming of P-values-based approaches in the assessment of clinical outcomes. The post-treatment changes and the MID in Oral Health-Related Quality of Life (OHRQoL) among adults undergoing fixed orthodontic treatment were investigated. METHODS: Ninety-two patients (29.1 ±â€…6.3 years old, 18 males and 74 females) were prospectively included. Oral Health Impact Profile (OHIP-14) and United Kingdom Oral Health-related Quality of Life (OHQoL-UK) were used to assess OHRQoL at baseline and post-treatment (50.8 ±â€…15.7 months). Global Transition Rating (GTR) was used to assess oral health/well-being, Peer Assessment Review (PAR), and Index of Complexity, Outcome and Need (ICON) were used to assess occlusion. Wilcoxon signed-rank test was used to assess changes in OHRQoL and occlusion, Kruskal-Wallis one-way ANOVA and Mann-Whitney U-test were used to assess associations between OHRQoL and oral health/well-being or occlusion. MID for OHIP-14 and OHQoL-UK was estimated via anchor-based (PAR, ICON, GTR) and distribution-based approach (effect size, standardized response mean, standard error of measurement). RESULTS: The median OHIP-14 and OHQoL-UK post-treatment scores were significantly changed, indicating improved OHRQoL. Based on the agreement between different methods, the MID of OHIP-14 and OHQoL-UK were at least 15 and 6 scale points, corresponding to a large effect size (1.5-1.7). CONCLUSIONS: Orthodontic treatment had a positive long-term impact on OHRQoL. MID for the OHIP-14 and OHQoL-UK provide guidance to interpreting the impact of orthodontic treatment on the OHRQoL of patients.

Clinical effectiveness of the Eruption Guidance Appliances in treating malocclusion in the mixed dentition: A systematic review and meta-analysis.

AIM: To evaluate the clinical effectiveness of the eruption guidance appliances (EGAs) in treating malocclusion in the early mixed dentition. DESIGN: Electronic databases were comprehensively searched for the eligibility literature of the EGA treatment for a period spanning from the earliest available date in each database up to July 2021. Randomized controlled trials, controlled clinical trials, and prospective and retrospective cohort studies were included in the present review. The quality of clinical trials was assessed according to the Cochrane Collaboration's tools (RoB2.0 and ROBINS-I), whereas cohort studies were based on the Newcastle-Ottawa Scale (NOS). The data were gathered and synthesized with the Stata software (version 12). RESULTS: The screen yielded 436 articles, of which 17 papers were potentially eligible, and 7 articles from 3 studies (1 RCT, 1 CCT, and 1 PCS) were qualified for the final review and analysis. The meta-analysis showed both favorable dentoalveolar and skeletal changes in short term. Both overjet and overbite had a significant decrease after treatment (MD = -2.38 mm, 95% CI: -2.82 to -1.94, p < .001, and MD = -2.43 mm, 95% CI: -3.52 to -1.35, p < .001, respectively), and SNB increased significantly by 0.73 degrees (95% CI: 0.17-1.28, p = .01). After the retention period, however, overbite had a significant increase of 0.88mm, which indicated the occurrence of a relapse (95% CI: 0.60-1.16, p < .001). CONCLUSIONS: According to the existing evidence, the EGA treatment is effectively correcting overjet and overbite in the early mixed dentition in short term; furthermore, high-quality and long-term studies are warranted to determine its long-term effectiveness.

Changes in the upper airway, hyoid bone and craniofacial morphology between patients treated with headgear activator and Herbst appliance: A retrospective study on lateral cephalometry.

BACKGROUND: The present study compared the treatment changes in the upper airway, hyoid bone position and craniofacial morphology between two groups of children with skeletal class II malocclusion treated with the headgear activator (HGA) and Herbst appliance (Herbst). SETTING AND SAMPLE POPULATION: Orthodontic population from the Faculty of Dentistry of the University of Hong Kong. METHODS: Thirty-four skeletal class II patients treated with the HGA (17 patients, mean age 10.6 ± 1.5 years) and the Herbst (17 patients, mean age 11.0 ± 1.4 years) were matched for sex, age, overjet, skeletal class and mandibular divergence. The patients received lateral cephalometric radiographs (LCRs) at the beginning of treatment (T1 ), after treatment (T2 ) and at follow-up (T3 ). In the HGA group, patients underwent LCRs 7 months before the beginning of treatment (T0 ), which were used as growth reference for intra-group comparison. Paired Student's t tests were used for intra- and inter-group comparisons (α = .05). RESULTS: Treatment changes (T2 -T1 ) did not differ significantly between the groups. However, at follow-up (T3 -T1 ) the Herbst group showed a smaller increase than the HGA group in the vertical position of the hyoid bone relative to the Frankfort plane (P = .013) and mandibular plane (P = .013). CONCLUSIONS: There were no significant differences in the upper airway, hyoid bone position and craniofacial morphology between the groups at the end of treatment. However, the Herbst may provide better long-term control of the vertical position of the hyoid bone than the HGA in children with skeletal class II malocclusion.

Orthodontic Treatment Need and the Psychosocial Impact of Malocclusion in 12-Year-Old Hong Kong Children.

OBJECTIVES: To determine the prevalence of orthodontic treatment need in 12-year-old children in Hong Kong and its relationship with the psychosocial impact of malocclusion and to assess their associations with sociodemographic factors. MATERIALS AND METHODS: A random sample of 687 12-year-old children was recruited from 45 secondary schools in Hong Kong. Orthodontic treatment need was assessed on study models by five indices: the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC), the Aesthetic Component of the IOTN (IOTN-AC), the Dental Aesthetic Index (DAI), the Index of Complexity Outcome and Need (ICON), and the Peer Assessment Rating (PAR). The psychosocial impact of malocclusion on participants and sociodemographic factors were obtained from a questionnaire. Logistic regression was used to examine the correlations between treatment need and the psychosocial impact of malocclusion as well as their associations with sociodemographic factors. RESULTS: The final number of participants was 667 (339 boys and 328 girls, participation rate 667/687 = 97.1%). The prevalence of orthodontic treatment need varied depending on the indices used (10.9-47.8%), but significant correlations were found among the five indices (p < 0.01). The uptake of treatment among the cohort was 2.3%. Boys had higher IOTN-DHC (p < 0.05), DAI (p < 0.05), and PAR (p = 0.05) scores than girls. IOTN-AC was significantly associated with the psychosocial impact of malocclusion (p < 0.05). Parents' level of education and household income were not significantly associated with either treatment need or the psychosocial impact of malocclusion (p > 0.05). CONCLUSION: The need for orthodontic treatment in 12-year-old children in Hong Kong remained high, and the uptake of treatment was low. Boys had a higher normative treatment need than girls. Among the five indices, IOTN-AC appears to be the best indicator of the psychosocial impact of malocclusion.

Upper Airway Changes following Functional Treatment with the Headgear Herbst or Headgear Twin Block Appliance Assessed on Lateral Cephalograms and Magnetic Resonance Imaging.

OBJECTIVE: The present study compared the changes in the upper airway dimensions and sleep-related breathing disorder (SRBD) condition between functional treatment with the headgear Herbst (HG-Herbst) and headgear Twin Block (HG-TB) appliance. Soft tissues were assessed on lateral cephalometric X-ray and magnetic resonance imaging (MRI). MATERIALS AND METHODS: Consecutive patients who sought orthodontic treatment at the Faculty of Dentistry of The University of Hong Kong were screened. Adolescents (12-17 year sold for boys and 10-15 years old for girls), with class II molar relationship and overjet >5 mm, with no severe transverse maxillary deficiency, were recruited. Patients were assigned either to the HG-Herbst or to the HG-TB treatment by stratified block randomisation, with sex as the stratification factor. Lateral cephalograms, magnetic resonance imaging (MRI), and the Paediatric Sleep Questionnaire (PSQ) were obtained at baseline and after treatment. RESULTS: 28 patients were enrolled, and 26 patients (13 in each group) completed the treatment. Following 1 year of functional appliance treatment, a significantly lower increase of the lower anterior facial height was observed in the HG-Herbst group compared to the HG-TB group (p = 0.024). However, no significant differences were observed in the upper airway structures or SRBD between the two groups. CONCLUSION: The changes in upper airway dimensions and SRBD condition were not significantly different between the HG-Herbst and the HG-TB appliance treatment. Additional studies with larger sample size are warranted.

Elastodontic appliance assisted fixed appliance treatment: A new two-phase protocol for extraction cases.

Elastodontic appliance (EA) is a type of removable appliance that has been widely used in interceptive orthodontics. The present case report describes a severe crowding case treated with a new two-phase protocol by using an EA and a fixed appliance. A 13-year-old patient with severe dental crowding, increased overjet and overbite on a skeletal Class II base was selected. The patient had four bicuspids extracted; during the first phase of treatment, she wore the EA for 2 h during the daytime plus overnight, combined with a myofunctional exercise. During the second phase of treatment, a fixed appliance was employed to close residual space and improve the teeth angulations. The total treatment time was 14 months, of which the second phase with fixed appliance lasted 10 months. Satisfactory improvements of the overjet and teeth alignment were achieved. This case report used a new two-phase treatment protocol which resulted in a favourable outcome after comparatively short treatment.

Digital Models as an Alternative to Plaster Casts in Assessment of Orthodontic Treatment Outcomes.

OBJECTIVE: This study aimed to compare the use of digital models and plaster casts in assessing the improvement in occlusion following orthodontic treatment. MATERIALS AND METHODS: Digital models and plaster casts of 39 consecutive patients at pre- and posttreatment stages were obtained and assessed using the Peer Assessment Rating (PAR) index and the Index of Complexity and Treatment Need (ICON). PAR and ICON scores were compared at individual and group levels. Categorization of improvement level was compared using Kappa (κ) statistics. RESULTS: There was no significant difference in neither PAR scores (p > 0.05) nor ICON scores (p > 0.05) between digital and plaster cast assessments. The Intraclass Correlation Coefficient (ICC) values for changes in PAR and ICON scores were excellent (ICC > 0.80). Agreement of ratings of occlusal improvement level between digital and plaster model assessments was 0.83 (κ) for PAR and 0.59 (κ) for ICON, respectively. CONCLUSION: The study supported the use of digital models as an alternative to plaster casts when assessing changes in occlusion at the 'individual patient' level using ICON or PAR. However, it could not fully support digital models as an alternate to plaster casts at 'the group level' (as in the case of clinical audit/research).

Change of mandibular position during two-phase orthodontic treatment of skeletal class II in the Chinese population.

The aim of this study was to evaluate the change in mandibular position during a two-phase orthodontic treatment of skeletal Class II malocclusion. Thirty consecutively treated Chinese male adolescents who had undergone two-phase treatment with Herbst appliance and fixed appliance and fulfilled the specific selection criteria were sampled. Cephalograms taken at T0 (before treatment), T1 (at the end of functional appliance treatment), and T2 (at the end of fixed appliance treatment) were analyzed. The change in sagittal positioning of the mandible was 6.8 ± 3.44 mm in phase I (T0-T1), 0.4 ± 2.79 mm in phase II (T1-T2), and 7.2 ± 4.61 mm in total. The mandible came forward in 100% of the patients at T1. In phase II, it came forward in one-third (positive group) remained unchanged in one-third (stable group) and went backward in one-third (negative group) of the patients. At T2, it came forward twice as much in the positive group compared to the negative group. Mandibular length was significantly increased in 100% of the patients in both phases. In conclusion, during the treatment with functional appliance, the mandibular prognathism increases in all patients, whereas during the treatment with fixed appliance there is no significant change in mandibular prognathism.

Natural compounds containing mouthrinses in the management of dental plaque and gingivitis: a systematic review.

OBJECTIVES: To evaluate the effectiveness of natural compounds containing mouthrinse (NCCM) as an adjunct to unsupervised oral hygiene in the management of dental plaque and gingivitis. MATERIALS AND METHODS: An electronic search for clinical studies of NCCMs was conducted in Medline-PubMed, the Cochrane Central Register of Controlled Trials and EMBASE for a period spanning from the earliest available date in each database up to February 2013. Plaque index, gingival index, and gingival bleeding index were selected as primary outcomes. The methodological quality of the studies was assessed according to the "Levels of Evidence" outlined by the Center of Evidence-Based Medicine, and to the Jadad scale. RESULTS: The screen yielded 2,236 titles and abstracts that met the inclusion criteria. These identified 11 clinical trials testing 13 different NCCMs, and were used for data extraction. Heterogeneity and the limited number of studies on any individual NCCM precluded a formal meta-analysis. Of the 13 NCCMs tested, eight demonstrated positive results, and few reported any adverse effects or events. CONCLUSIONS: Evidence proving the effectiveness of NCCM as an adjunct to unsupervised oral hygiene for plaque and gingivitis control is still insufficient. However, some natural products (compounds) may have oral health benefits, so further high-quality study is warranted. CLINICAL RELEVANCE: This review provides an overview of the strength of clinical evidence regarding the effectiveness of natural compounds containing mouthrinses in promoting gingival health.

Acid etching of human enamel in clinical applications: a systematic review.

STATEMENT OF PROBLEM: The laboratory-based enamel acid-etching doctrine with 30% to 50% phosphoric acid for 60 seconds to generate the maximum amount of Type 1 and/or Type 2 etch pattern has been established for more than 30 years. However, this recommendation may not be clinically relevant. PURPOSE: The purpose of this systematic review was to compare clinically accepted protocols of enamel acid etching with the laboratory protocol. MATERIAL AND METHODS: Studies were identified by searching 4 electronic databases: Medline, CINAHL Plus, Embase, and Cochrane Library. The final search was run on November 8, 2012. All clinical studies published in English that investigated enamel acid pretreatment methods on human permanent teeth were included. Additional publications were obtained from the reference lists of the included studies. The clinical evidence of all included studies was tabulated. RESULTS: Initially, 4543 publications were retrieved from the databases. A total of 4508 articles were excluded, including 2285 duplicates, 1805 publications according to exclusion criteria by their titles and abstracts, 368 laboratory articles, 49 reviews, and 1 pilot study. Only 1 study was added from reference lists of the included studies. Finally, 36 clinical publications were included. The included clinical studies provided different levels of clinical evidence on the efficacy of acid-etching protocols to enable successful enamel adhesion. CONCLUSIONS: Clinical protocols of enamel acid etching differ from the laboratory-generated doctrine, which may imply that maximization of the Type 1 and/or Type 2 etch pattern is not important in the clinical acid etching of human enamel.

The effects of natural compounds-containing mouthrinses on patients with fixed orthodontic appliance treatment: clinical and microbiological outcomes.

AIM: To investigate the effects of two natural compounds-containing mouthrinses (NCCMs) (a fructus mume (FM) extract-containing mouthrinse and an essential oil (EO)-containing mouthrinse) on gingival health and microbial profiles in young orthodontic patients. DESIGN: This 6-month randomized, single-blinded, parallel-controlled clinical trial consists of 90 patients with fixed appliance treatment. The subjects were allocated to (1) negative control group: oral hygiene instruction (OHI) alone; (2) test group 1: OHI plus EO mouthrinse; and (3) test group 2: OHI plus FM mouthrinse. Clinical examinations included plaque index (PI), bleeding index (BI) and modified gingival index (MGI). Salivary microbial quantifications included total aerobic and anaerobic bacteria, Streptococci and Lactobacilli counts. Clinical and microbiological examinations were conducted at baseline, 3rd and 6th months (T1, T2, and T3). RESULTS: BI was significantly reduced in both the FM mouthrinse and EO mouthrinse groups compared with the negative control group at T3 (P < 0.05). There were no significant intergroup differences in salivary bacteria counts in all groups (P > 0.05). CONCLUSION: Both NCCMs effectively reduced gingival bleeding without causing significant alterations of microbial profile in young orthodontic patients.

Lingual retainers bonded without liquid resin: a 5-year follow-up study.

INTRODUCTION: The aim of this in-vivo study study was to evaluate the effect of excluding the liquid resin component of a composite bonding product that is based on bisphenol A diglycidylmethacrylate when bonding lingual retainers. METHODS: The material comprised 40 metal multistrand lingual retainers bonded onto the lingual surfaces of maxillary and mandibular anterior teeth. Transbond LR composite paste and liquid resin (3M Unitek, Monrovia, Calif) were used to bond retainers in the control group (20 retainers). The same bonding material was used in the test group (20 retainers), but the liquid resin component was excluded. The durations (in months) of retainer survival were analyzed by using the Kaplan-Meier product limit method and the log rank test. RESULTS: Fifty percent of the retainers in the control group and 60% of those in the test group had no bond failures during the 5-year observation period; the difference was not statistically significant. Bond failures were recorded in 13.6% of the bonded tooth surfaces in the control group and in 14.9% in the test group; the difference was not statistically significant. On average, the retainers stayed intact in the control and test groups for 36 and 32 months, respectively. The median survival times of the control and test groups were 43 months and more than 47 months, respectively. Neither the survival analysis nor the 95% confidence intervals (24-49 months in the control group, 24-40 months in the test group) suggested any statistically significant difference between the groups. CONCLUSIONS: Metal lingual retainers can be successfully bonded without liquid resin and serve the patient equally as well clinically as retainers bonded with the conventional bonding technique.

Prunus mume extract exhibits antimicrobial activity against pathogenic oral bacteria.

OBJECTIVES: Prunus mume is a common fruit in Asia, which has been used in traditional Chinese medicine. In this study, we focused on the antimicrobial properties of Prunus mume extract against oral pathogens related to dental caries and periodontal diseases. STUDY DESIGN: A total of 15 oral pathogens including Streptococcus mutans, S. sobrinus, S. mitis, S. sanguinis, Lactobacillus acidophilus, P. gingivalis, Aggregatibacter actinomycetemcomitans, and Candida species were included in the study. Initially, agar diffusion assay was performed to screen the antimicrobial activities of Prunus mume extract. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were then determined for sensitive species. Effect of Prunus mume extract on human oral keratinocytes (HOK) viability was also tested. RESULT: In the agar diffusion assay, drug suspension of 2 g/mL was able to inhibit all the bacterial species tested, but not the fungal species. MIC and MBC range of Prunus mume extract against the oral bacteria was 0.15625-0.0003 g/mL and P. gingivalis being the most susceptible species. Prune extract did not cause any detrimental effect on HOK. CONCLUSION: Prunus mume extract may be a potential candidate for developing an oral antimicrobial agent to control or prevent dental diseases associated with oral pathogenic bacteria.

Changes in oral health-related quality of life during fixed orthodontic appliance therapy: an 18-month prospective longitudinal study.

INTRODUCTION: There is an increasing research interest in quality of life issues in orthodontics. In this study, we aimed to investigate changes in oral health related quality of life (OHRQoL) among adults during fixed orthodontic appliance therapy (FOAT). METHODS: Two hundred thirty-two adult patients were enrolled from a consecutive sample at a university dental hospital. OHRQoL was assessed by 2 standardized instruments (OHIP-14 and OHQoL-UK) at 4 times: before treatment (T0), 6 months after bonding and banding (T1), 12 months after bonding and banding (T2), and 18 months after bonding and banding (T3). Friedman 2-way analysis of variance (ANOVA) and Wilcoxon signed rank tests were used to compare the relative changes of OHRQoL among the different time points. RESULTS: Significant changes in the summary scores of both the OHIP-14 and OHQoL-UK were observed during fixed orthodontic treatment (P <0.001). There were significant OHRQoL deteriorations at T1 and T2 compared with T0; these were reflected by summary scores of both the OHIP-14 and OHQoL-UK as well as some of their domain scores (P <0.05). However, at T3, the OHIP-14 suggested deterioration in OHRQoL, but the OHQoL-UK suggested improvement in OHRQoL. CONCLUSIONS: Changes in OHRQoL occur during fixed orthodontic appliance therapy. In the early phase of treatment, the greatest deterioration in OHRQoL occurs. With ongoing treatment, the detrimental effects to OHRQoL are reduced.

Comparison of the antimicrobial activity of Listerine and Corsodyl on orthodontic brackets in vitro.

INTRODUCTION: The aim of this study was to evaluate the antimicrobial efficacy of 2 commercially available mouth rinses on a monospecies-biofilm model on orthodontic brackets in vitro. METHODS: The antimicrobial effects of the 2 mouth rinses, Listerine (tartar control; IDS Manufacturing, Bangkok, Thailand) and Corsodyl (SmithKline Beecham, Maidenhead, United Kingdom), on the planktonic Streptococcus mutans were tested by maximum inhibitory dilution assay. The cell viability of S mutans biofilm on Damon3 MX brackets (Ormco, Glendora, Calif) after exposure to the 2 mouth rinses was quantified by 2,3-bis (2-methoxy-4-nitro-5-sulfophenyl)-5-[(phenylamino) carbonyl]-2H-tetrazolium hydroxide (XTT) reduction assay. Visualization of the biofilm samples was performed by fluorescence microscopy and confocal laser scanning microscopy. RESULTS: The maximum inhibitory dilution assays of S mutans were 1:5 for Listerine and 1:320 for Corsodyl. The optical density values, which were measured by XTT reduction assay from S mutans biofilms after 1 minute of exposure to the different test agents, demonstrated that the cell viability of S mutans biofilms exposed to Listerine was less than that for Corsodyl, which was less than that for brain-heart infusion (P <0.001). Listerine caused more dead cells on the surface of the brackets than did Corsodyl when examined with the 2 microscope systems. CONCLUSIONS: Both mouth rinses showed marked antimicrobial effects on the monospecies biofilm in vitro. Listerine showed a stronger bactericidal effect but had less bacterial inhibitory effect than did Corsodyl.

A systematic review of the efficacy of oral appliance design in the management of obstructive sleep apnoea.

Oral appliances (OAs) are increasingly advocated as a treatment option for obstructive sleep apnoea (OSA). However, it is unclear how their different design features influence treatment efficacy. The aim of this research was to systematically review the evidence on the efficacy of different OAs on polysomnographic indices of OSA. A MeSH and text word search were developed for Medline, Embase, Cinahl, and the Cochrane library. The initial search identified 1475 references, of which 116 related to studies comparing OAs with control appliances. Among those, 14 were randomized controlled trials (RCTs), which formed the basis of this review. The type of OA investigated in these trials was mandibular advancement devices (MADs), which were compared with either inactive appliances (six studies) or other types of MADs with different design features. Compared with inactive appliances, all MADs improved polysomnographic indices, suggesting that mandibular advancement is a crucial design feature of OA therapy for OSA. The evidence shows that there is no one MAD design that most effectively improves polysomnographic indices, but that efficacy depends on a number of factors including severity of OSA, materials and method of fabrication, type of MAD (monobloc/twin block), and the degree of protrusion (sagittal and vertical). These findings highlight the absence of a universal definition of treatment success. Future trials of MAD designs need to be assessed according to agreed success criteria in order to guide clinical practice as to which design of OAs may be the most effective in the treatment of OSA.

Ultrastructure and morphology of biofilms on thermoplastic orthodontic appliances in 'fast' and 'slow' plaque formers.

The aim of this study was to investigate the morphological features and distribution of biofilms on Invisalign orthodontic appliances, in a sample of 'slow' and 'fast' plaque formers using scanning electron microscopy (SEM). Fifty-six Chinese male/female volunteers (aged 19-39 years) were screened for their plaque-forming rate using the plaque percentage index (PPI) coupled with digital photography and computer-based image analysis, after a period of 48 hours of abstinence from oral hygiene procedures. Eleven volunteers (seven males/four females) representing the lowest and highest ends of the plaque formation spectrum were chosen as slow and fast plaque formers, respectively. The subjects wore a full-coverage splint appliance, in which four tiles of Invisalign material were embedded. These tiles were collected at intervals of 1, 3, 6, 12, 24, and 48 hours, as well as 3, 7, and 14 days, immediately fixed in 10 per cent paraformaldehyde in 0.2 M cacodylate buffer solution and prepared for SEM. The surface configuration of the Invisalign appliance was visualized, as well as the chronological pattern of biofilm formation. Significance between fast and slow plaque formers was determined using a Student's t-test. Colonization appeared to centre initially on the raised edges or textured surfaces of the appliance, and initial adhesion was quicker and more abundant in the fast plaque-forming group. In the later stages of biofilm development, both groups showed no discernible differences in biofilm accrual on the surfaces, but the fast group displayed a more complex biofilm structure. More recessed and sheltered areas of the appliance, such as the cusp tips and attachment dimples, harboured more biofilm than the flat surfaces. Hence, it seems that the novel Invisialign orthodontic appliance is a useful tool to investigate the features of biofilm formation in time-course studies.

Differences in dentofacial characteristics between southern versus northern Chinese adolescents.

AIM: To compare the dentofacial characteristics of southern and northern Chinese adolescents. METHODS: A southern Chinese sample comprised 70 males (Mean age 12.4 +/- 0.60 years) and 60 females (Mean age 12.5 +/- 0.4 years), and a northern Chinese sample consisted of 50 males (Mean age 12.8 +/- 1.8 years) and 50 females (Mean age 12.4 +/- 1.2 years). All subjects had a Class I molar relationship with no or minimal crowding, a well balanced cephalometric profile, and no history of orthodontic treatment. Patient cephalograms were traced and digitized and McNamara's analysis applied. RESULTS: A smaller midface and a shorter overall mandibular length were observed in southern Chinese, whereas significantly increased vertical dimension and a retrusive chin were noted in northern Chinese. Protrusive upper and lower incisors and a protrusive upper lip were found in southern Chinese. CONCLUSIONS: There were significant differences in dentofacial morphology between southern and northern Chinese adolescents. It is suggested that separate cephalometric norms be used for patients originating from different parts of China.

Unilateral Scissor Bite Managed with Prefabricated Functional Appliances in Primary Dentition-A New Interceptive Orthodontic Protocol.

A unilateral scissor bite is a type of severe malocclusion in primary dentition that can influence the development of the mandible and face. The present case report describes an interceptive treatment on a 4-year-old girl with a unilateral scissor bite combined with an anterior crossbite, increased reverse overjet, and overbite on a skeletal Class III base. The patient was treated with a new Prefabricated Functional Appliance (PFA) which was modified from a Frankel-III appliance to induce a mandible to move backwards and relieve an occlusion discrepancy of the dental arch, and a functional dental rehabilitation with resin and myofunctional exercises with a PFA which was modified from an oral screen appliance were performed during the treatment. The total treatment time was 11 months and a satisfactory improvement of occlusion and facial esthetics was achieved. This case report presents a new PFA system and treatment protocol in primary dentition which results in a favorable outcome, and the clinical effectiveness of this appliance system warrants further investigation.