Effect of Orthopedic Treatment for Class III Malocclusion on Upper Airways: A Systematic Review and Meta-Analysis

Gender-based Comparison of Pharyngeal Airway Between Class I and Class III Patients During MP3cap Growth Period

Objective

To compare the pharyngeal airway size and area between Class III patients exhibiting optimal vertical growth direction and Class I patients at the MP3cap stage, considering gender differences.

Methods

This retrospective study analyzed pre-treatment cephalograms of a total of 180 patients with Class I (45 girls, 45 boys) and Class III (maxilla or maxillo-mandibular origin) (45 girls, 45 boys) malocclusions. Linear and angular measurements were conducted on lateral cephalograms utilizing the GNU Image Manipulation Program (GIMP 2.10.18, NY, USA; https://www.gimp.org/). The pharyngeal airway areas were computed utilizing AUTOCAD (Autodesk 2018, San Rafael, CA, USA). The Independent Samples t-test and Mann-Whitney U test were employed for comparative analysis of variables across groups. The forward selection method was employed in conjunction with regression analysis.

Results

No significant differences were observed in the nasopharyngeal area (NA; mm2) across the malocclusion groups and genders. In Class III girls, the oropharyngeal area (OA; mm2), retroglossal (RG; mm2) area, and superior pharyngeal space (SPS; mm) were significantly larger than those of Class III boys, and Class I girls (p<0.05). The inferior pharyngeal space (IPS; mm) was significantly larger in Class III girls compared to Class III boys (p<0.05). Girls with Class I/III malocclusions demonstrated a more pronounced head posture than boys (p<0.05).

Conclusion

The findings indicate the necessity of accounting for gender-specific variations in Class I and III patients, as well as evaluating pharyngeal airway characteristics in orthodontic diagnosis and treatment planning. In Class III girls, the OA and RG areas, as well as the superior and inferior pharyngeal spaces, were larger compared to Class III boys.

Extraction of premolars in orthodontic treatment does not negatively affect upper airway volume and minimum cross-sectional area: a systematic review with meta-analysis

BACKGROUND

Extraction of premolars is usually prescribed for the orthodontic treatment of cases with inadequate space within the dental arch or when anterior teeth retraction is indicated; however, it has been advocated that this treatment approach could negatively influence the airways.

OBJECTIVE

To identify and critically appraise studies of premolar extractions during orthodontic treatment on upper airway dimensions. Search methods: Electronic unrestricted searches in nine databases until October 2024. Selection criteria: Clinical studies on humans comparing comprehensive orthodontic treatment with versus without the extraction of premolars using cone-beam computed tomography to assess upper airway volume or minimum cross-sectional area (minCSA). Data collection and analysis: After duplicate study selection, data extraction, and risk-of-bias assessment according to Cochrane, random-effects meta-analyses of Mean Differences (MD) with their 95% confidence intervals (CI) were performed, followed by subgroup/meta-regression analyses and assessment of the quality of evidence.

RESULTS

Twelve papers corresponding to 11 unique retrospective non-randomized studies were included, covering 891 patients (35.8% male; 20.0 years-old on average). No statistically significant differences in the effect of orthodontic treatment on the volume of the nasopharynx, palatopharynx, glossopharynx, oropharynx or oral cavity were seen between patients treated with versus without premolar extractions (P > .05). Similarly, no significant differences were seen between extraction and non-extraction patients in terms of minCSA of the nasopharynx, palatopharynx, or glossopharynx (P > .05). On the contrary, patients treated with premolar extractions showed increased minCSA of the oropharynx compared to those treated without premolar extractions (4 studies; MD = 23.00 mm2; 95% CI = 10.74-35.26 mm2; P = .009). No significant effects from patient age, sex, or equivalence of the extraction/non-extraction groups were found, while the strength of evidence was moderate in all cases due to the inclusion of non-randomized studies with high risk of bias.

CONCLUSIONS

Limited evidence of moderate strength indicates that, on average, premolar extractions during comprehensive orthodontic treatment have little to no effect on the volume and minCSA of the airways.

REGISTRATION

CRD42024621355.

Mapping the evolving trend of research on Class III malocclusion: a bibliometric analysis

OBJECTIVES

This study aimed to provide visualized knowledge maps to show the evolving trends and key focal points of Class III malocclusion research through a comprehensive bibliometric analysis.

MATERIALS AND METHODS

Class III malocclusion research published between 2000 and 2023 was retrieved from the Web of Science Core Collection. VOSviewer was utilized to count the citation and publication number of authors, institutions, countries and journals. Co-occurrence, co-citation, and cluster analyses and burst detection were conducted using CiteSpace.

RESULTS

A total of 3,682 publications on Class III malocclusion were included in the bibliometric analysis. During 2000-2023, both the annual publication count and citation frequency exhibited a gradual upward trajectory, with a noticeable surge in recent years. In terms of production and citation counts of Class III malocclusion research, the core journal is the American Journal of Orthodontics and Dentofacial Orthopedics. Furthermore, apart from the primary keyword 'Class III malocclusion', 'orthognathic surgery' was identified as keyword with the most frequency. The cluster analysis of cited references reveals that the research focal points have shifted to 'skeletal anchorage' and 'surgery-first approach'. Furthermore, the burst detection identified 'quality of life' as a potential research hotspot since it has recently gained increasing scholarly attention.

CONCLUSIONS

The current study provides scholars with the knowledge maps of evolving trends and prominent topics of Class III malocclusion research and a summary of research progress on various priorities during different periods. These findings are expected to provide a valuable guidance to facilitate the future research on Class III malocclusion.

Effects of nano-micelles curcumin-based photodynamic therapy on expression of RUNX2 as an indicator of bone regeneration in orthodontic tooth movement

OBJECTIVES

The aim was to evaluate the impact of nano-micelles curcumin (NMCur) based photodynamic therapy (PDT) during compressive force application on human PDL-derived fibroblasts (HPDFs) in vitro for up to 6 days on the expression of RUNX2 as an indicator of bone development and remodeling.

MATERIALS AND METHODS

HPDFs viability during 2 g/cm2 compressive force application was investigated using membrane-impermeable DNA-binding stain propidium iodide (PI) in flow cytometry. Gene and protein expressions of RUNX2 were assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and flow cytometry, respectively, following NMCur-PDT at different concentrations of NMCur (25, 50, and 75 µM plus irradiation of 180 mW/cm2 diode laser at the wavelength of 450 ± 10 nm for 5 min) during the static compressive force of 2 g/cm2 on HPDFs via weight approach-based in-vitro loading model up to 6 days. One-way ANOVA and Tukey post hoc tests at a p-value equal to/or less than 0.05 were used to analyze the obtained data.

RESULTS

After 6 days of application of compressive force, 99.21 ± 6.12% of HPDFs were PI negative and therefore considered alive, while only 0.89 ± 0.06% of the population were PI positive and considered dead. In comparison with controls (loaded HPDFs), expression of RUNX2 gene was dose-dependent and the highest expression (14.38-fold; P < 0.01) was observed at a concentration of 75 µM NMCur following 5 min of diode laser irradiation (i.e., 75 µM NMCur-PDT) during compressive force application on day 5. The greatest and lowest upregulations of RUNX2 protein were observed in 75 µM NMCur-PDT during compressive force application on HPDFs, on day 5 (3.19-fold; P < 0.01) and day 6 (2.09-fold; P < 0.05), respectively.

CONCLUSION

NMCur-PDT during weight approach-based in-vitro loading model can promote orthodontic tooth movement by upregulating RUNX2 signaling pathway in HPDFs.

Effect of SEC III protocol on upper airway dimensions in growing class III patients: a retrospective study

BACKGROUND

The primary objective of the study was to evaluate the effects of SEC III (Splints, Class III Elastics, and Chin cup) protocol on the upper airway dimensions using lateral cephalometric radiographs. The secondary objectives were to evaluate the skeletal and dental effects of the SEC III protocol using lateral cephalometric radiographs.

METHODS

The pre- and post-treatment lateral cephalometric radiographs of 24 patients treated using the SEC III protocol were used to address the aim of the study. Children in the pre-pubertal (CS-1 or CS-2) or circumpubertal (CS-3 or CS-4) skeletal maturation stage and having class III dentoskeletal malocclusion were included in the study. Patients with a history of previous orthodontic treatment, maxillofacial surgery or trauma, tonsillectomy, adenoidectomy, or craniofacial malformations were excluded. The pre-treatment and post-treatment lateral cephalometric radiographs were traced, then airway measurements, skeletal measurements, and dental measurements were performed. The results were analysed using paired samples t-test or Wilcoxon signed rank test according to the data normality.

RESULTS

Data of 6 males and 18 females were analysed (Mean age = 11.21 ± 1.02 years). Duration of active treatment was 5.75 ± 1.03 months. Treatment using SEC III protocol resulted in a significant increase in ANB angle (2.92 ± 1.50 degrees, p < 0.001) and Wits appraisal (3.31 ± 1.99 mm) (p < 0.001). The increase in the mandibular plane angle (0.75 ± 1.42 degrees, p = 0.02) and the maxillary length (2.29 ± 2.69 mm, p < 0.001) was statistically significant. Contrarily, the mandibular length did not change significantly (p = 0.10). The maxillary incisors were significantly proclined (4.38 ± 4.28 degrees; p < 0.001), while the mandibular incisors were significantly retroclined (-5.79 ± 6.21 degrees; p < 0.001) following treatment. The change in the nasopharyngeal airway and the retropalatal airway was not statistically significant. The middle and inferior pharyngeal space (retroglossal airway) significantly decreased by 1.33 ± 1.97 mm (p = 0.003) and 1.96 ± 2.48 mm (p = 0.001), respectively.

CONCLUSIONS

Early class III correction using SEC III protocol reduced the retroglossal airway dimensions but did not affect the nasopharyngeal and retropalatal airway dimensions. Correction of the class III dentoskeletal relationship was obtained through both skeletal and dental changes.

Effectiveness of orthopaedic treatments on the enlargement of the upper airways: Overview of systematic reviews

OBJECTIVE

The aims of this overview are to evaluate the three-dimensional effects of orthopaedic treatment (OT) and myofunctional therapy (MT) on the enlargement of the upper airways (UA).

METHODS

A search of the MEDLINE/PubMed and EMBASE databases was conducted up to July 2022 and completed by hand search. After selection of the title and abstract, systematic reviews (SR) dealing with the impact of OT and/or MT on UA containing only controlled studies were included. The methodological quality of the SR was assessed by the AMSTAR-2, Glenny and ROBIS tools. A quantitative analysis was done with Review Manager 5.4.1.

RESULTS

Ten SR were included. The risk of bias was judged low for one SR according to ROBIS. Two SR presented a high level of evidence according to AMSTAR-2. In the quantitative analysis and about the orthopaedic mandibular advancement therapies (OMA), while a significant increase in superior (SPS) [(Mean difference (MD): 1.19; CI 95% [0.59; 1.78]; P<0.0001)] and middle (MPS) pharyngeal space [(MD: 1.10; CI 95% [0.22; 1.98]; P=0.01)] existed in the short-term for both OMA, it was greater for removable. On the other hand, there was no significant change in the inferior pharyngeal space (IPS). Four other SR targeted the short-term efficacy of class III OT. Only treatments with face mask (FM) or face mask+rapid maxillary expansion (FM+RME) allowed a significant increase in SPS [(MD FM: 0.97; CI 95% [0.14; 1.81]; P=0.02/MD FM+RME: 1.54; CI 95% [0.43; 2.66]; P=0.006)]. This was neither the case for chin cup nor in all cases in IPS. The last two SR explored the effectiveness of RME, whether or not associated with bone anchorage, on the dimensions of the UA or on the reduction of the apnoea/hypopnea index (AHI). A significant superiority of the effects of the devices with mixed or only bone anchorages existed concerning the width of the nasal cavity, the nasal airflow and the reduction of the nasal resistance. But, the qualitative analysis showed no significant reduction in AHI after RME.

CONCLUSIONS

Despite the heterogeneity of the included systematic reviews and their unfortunately not always low risk of bias, this synthesis showed that orthopaedics could provide some short-term improvement in AU dimensions, mainly in the upper and middle areas. Indeed, no devices improved the IPS. Class II orthopaedics improved SPS and MPS; class III orthopaedics, except for the chin cup, improved only SPS. RME, optimised with bone or mixed anchors, mostly improved the nasal floor.

Obstructive sleep apnea: a review for the orthodontist

INTRODUCTION

Obstructive sleep apnea (OSA) affects an important part of the population and is characterized by recurrent total or partial obstruction of the upper airway (UA) during sleep, negatively affecting the quality of life of patients in the short and long terms, and constituting an important public health problem for the society. The field of expertise of orthodontists is closely related to the UA, placing them in a strategic position to diagnose air passage failures and intervene when necessary. Orthodontists, as health professionals, must know how to recognize respiratory problems and manage them appropriately, when indicated.

OBJECTIVE

Thus, this paper aims to review and critically evaluate the related literature, to provide orthodontists with updated knowledge on the diagnosis and therapy related to OSA. Science and technology are constantly evolving; thus, the literature was also reviewed considering new technologies available in consumer-targeted applications and devices for the diagnosis, monitoring, and treatment of sleep-disordered breathing.

Craniofacial treatment protocol for a pediatric patient with obstructive sleep apnea and skeletal Class III malocclusion: A 13-year follow-up

This report aimed to describe the long-term effects of craniofacial growth modification treatment on sleep and breathing functions in a 7-year-old girl diagnosed with skeletal Class III malocclusion and sleep-disordered breathing. Based on the flowchart of orthodontic intervention protocol that we proposed for phenotype-based patient selection and skeletal target-based treatment selection for pediatric patients with sleep-disordered breathing, a 2-phase treatment targeting the nasomaxillary complex was performed. Posttreatment 3-dimensional changes in the skeletal structure and upper airway were evaluated in association with functional assessment using a validated pediatric sleep questionnaire and home sleep test. Esthetic improvement and obstructive sleep apnea cure were achieved without skeletal surgery. The 2-year retention records showed stable occlusion and improved facial profile with normal breathing and sleep.

Skeletal Changes in Growing Cleft Patients with Class III Malocclusion Treated with Bone Anchored Maxillary Protraction-A 3.5-Year Follow-Up

This prospective controlled trial aimed to evaluate the skeletal effect of 3.5-years bone anchored maxillary protraction (BAMP) in growing cleft subjects with a Class III malocclusion. Subjects and Method: Nineteen cleft patients (11.4 ± 0.7-years) were included from whom cone beam computed tomography (CBCT) scans were taken before the start of BAMP (T0), 1.5-years after (T1) and 3.5 y after (T2). Seventeen age- and malocclusion-matched, untreated cleft subjects with cephalograms available at T0 and T2 served as the control group. Three dimensional skeletal changes were measured qualitatively and quantitatively on CBCT scans. Two dimensional measurements were made on cephalograms. Results: Significant positive effects have been observed on the zygomaticomaxillary complex. Specifically, the A-point showed a displacement of 2.7 mm ± 0.9 mm from T0 to T2 (p < 0.05). A displacement of 3.8 mm ± 1.2 mm was observed in the zygoma regions (p < 0.05). On the cephalograms significant differences at T2 were observed between the BAMP and the control subjects in Wits, gonial angle, and overjet (p < 0.05), all in favor of the treatment of Class III malocclusion. The changes taking place in the two consecutive periods (ΔT1-T0, ΔT2-T1) did not differ, indicating that not only were the positive results from the first 1.5-years maintained, but continuous orthopedic effects were also achieved in the following 2-years. Conclusions: In conclusion, findings from the present prospective study with a 3.5-years follow-up provide the first evidence to support BAMP as an effective and reliable treatment option for growing cleft subjects with mild to moderate Class III malocclusion up to 15-years old.

Determining the short-term effects of different maxillary protraction methods on pharyngeal airway dimensions

OBJECTIVE

This study sought to evaluate the effects of different maxillary protraction methods on the pharyngeal airway in Class III patients with maxillary retrognathia.

SETTING AND SAMPLE POPULATION

A total of 59 individuals (31 females and 28 males) with a mean age of 11.38 ± 1.24 years were included in this study.

MATERIAL AND METHODS

Fifty-nine treated maxillary retrognathic patients who underwent different protraction methods were evaluated. Twenty patients treated with RME (Rapid Maxillary Expansion) made up the first group, and 20 patients treated with 5-week Alt-RAMEC (Alternate Rapid Maxillary Expansion and Constriction) protocol comprised the second group. Lastly, 19 patients on whom face masks with miniplates were applied were included in the skeletal anchorage (SA) group. Sixteen linear and four areal pharyngeal airway measurements were made on lateral cephalograms before and after treatment. Differences between the groups were assessed using analysis of variance (ANOVA) tests.

RESULTS

The mean maxillary protraction levels were determined as 2.7, 3.69 and 4.01 mm in the RME, Alt-RAMEC and SA groups, respectively. In the nasopharynx, AD1-PNS, AD2-PNS, PNS-Ba and PNS-Ho measurements revealed a significant increase in the SA group compared to the other groups (P < .05). In the oropharynx, PNS-Ep measurement increased significantly in the RME group (P < .05). In the total pharyngeal airway area, an increase was detected in the SA, Alt-RAMEC, and RME groups.

CONCLUSION

The most effective protraction method in terms of pharyngeal airway dimensions, especially in the nasopharynx, is the application of the face mask with skeletal anchorage. A greater increase in vertical airway length (PNS-Ep) was observed with RME.

Orthopedic Treatment for Class II Malocclusion with Functional Appliances and Its Effect on Upper Airways: A Systematic Review with Meta-Analysis

Aim of this systematic review was to assess the effects of orthopedic treatment for Class II malocclusion with Functional Appliances (FAs) on the dimensions of the upper airways. Eight databases were searched up to October 2020 for randomized or nonrandomized clinical studies on FA treatment of Class II patients with untreated control groups. After duplicate study selection, data extraction, and risk of bias assessment according to Cochrane guidelines, random effects meta-analyses of mean differences (MDs) and their 95% confidence intervals (CIs) were performed, followed by subgroup/meta-regression analyses and assessment of the quality of evidence. A total of 20 nonrandomized clinical studies (4 prospective/16 retrospective) including 969 patients (47.9% male; mean age 10.9 years) were identified. Orthopedic treatment with FAs was associated with increased oropharynx volume (MD = 2356.14 mm³; 95% CI = 1276.36 to 3435.92 mm³; p < 0.001) compared to natural growth. Additionally, significant increases in nasopharynx volume, minimal constricted axial area of pharyngeal airway, and airway were seen, while removable FAs showed considerably greater effects than fixed FAs (p = 0.04). Finally, patient age and treatment duration had a significant influence in the effect of FAs on airways, as had baseline matching and sample size adequacy. Clinical evidence on orthopedic Class II treatment with FAs is associated with increased upper airway dimensions. However, the quality of evidence is very low due to methodological issues of existing studies, while the clinical relevance of increases in airway dimensions remains unclear.

Comparison of two protocols for early treatment of dentoskeletal Class III malocclusion: Modified SEC III versus RME/FM

OBJECTIVE

To compare the short-term cephalometric outcomes of the protocols modified splints, Class III elastics, chincup (SEC III) and rapid maxillary expansion and facial mask (RME/FM) for the early treatment of growing subjects with Class III dentoskeletal malocclusion.

SETTINGS AND SAMPLE POPULATION

This retrospective observational study included 20 patients (11 males, nine females) treated with the modified SEC III protocol and 31 patients (16 males, 15 females) treated with the RME/FM one. The sample was evaluated before (T1, mean age 7.9 ± 1.0 years) and at the end of treatment (T2, mean age 9.0 ± 1.0 years). Statistical comparisons between the two groups were performed with independent sample t tests.

RESULTS

Both the modified SEC III and the RME/FM sample groups showed significantly favourable effects in terms of maxillary advancement (SNA +1.3° and +1.5°, respectively), control of mandibular projection (SNB -0.5° and -0.8°, respectively), and intermaxillary relationships (ANB +1.8° and +2.3°, respectively; Wits +3.4 and +1.9 mm, respectively). The modified SEC III group showed a statistically significant greater control in the intermaxillary divergency considering the SN to Pal. Pl. (P < 0.006) and Pal. Pl. to Mand. Pl. angle (P < 0.002) with a difference of 2.3 mm between the two groups.

LIMITATIONS

The main limitations of this study are its retrospective nature and the short-term outcomes.

CONCLUSION

Early treatment of growing patients with dentoskeletal Class III disharmonies is efficient using either modified SEC III or RME/FM protocols. However, a higher vertical control is achieved with the modified SEC III.

Effect of Orthopedic Treatment for Class III Malocclusion on Upper Airways: A Systematic Review and Meta-Analysis

The aim of this systematic review is to compare the effect on the upper airways of orthopedic treatment for skeletal Class III malocclusion with untreated controls. Nine databases were searched up to August 2020 for randomized or nonrandomized clinical trials comparing orthopedic Class III treatment (facemask or chin-cup) to untreated Class III patients. After duplicate study selection, data extraction, and risk of bias assessment (Risk Of Bias In Non-randomized Studies - of Interventions [ROBINS-I]), random-effects meta-analyses of Mean Differences (MDs)/Standardized Mean Differences (SMD) and 95% Confidence Intervals (CIs) were performed, followed by the Grading of Recommendations Assessment, Development and Evaluation assessment evidence-quality. A total of 10 papers (9 unique nonrandomized studies) with 466 patients (42.7% male; average age 9.1 years) were finally included. Limited evidence indicated that compared to normal growth, maxillary protraction with facemask was associated with increases in total airway area (n = 1; MD = 222.9 mm²; 95% CI = 14.0-431.7 mm²), total nasopharyngeal area (n = 4; SMD = 1.6; 95% CI = 1.2-2.0), and individual airway dimensions (upper-airway MD = 2.5 mm; lower-airway MD = 2.1 mm; upper-pharynx MD = 1.6 mm; lower-pharynx MD = 1.0 mm; all n = 6). Subgroup/meta-regression analyses did not find any significant effect-modifiers, while the results were retained 2-5 years postretention. Our confidence in these estimates was, however, very low, due to the inclusion of nonrandomized studies with methodological issues. Limited data from 2 chin-cup studies indicated smaller benefits on airway dimensions. Existing evidence from controlled clinical studies on humans indicates that maxillary protraction for skeletal Class III treatment might be associated with increased airway dimensions, which are, however, mostly minor in magnitude.