New insights on age-related association between nasopharyngeal airway clearance and facial morphology

Influences of Adenoid Hypertrophy on Children's Maxillofacial Development

This study aims to investigate the association between adenoid hypertrophy and facial development. A total of 388 children aged 1-13 years old who had undergone head MRI in Foshan Maternal and Child Health Hospital were collected, including 196 hypertrophic cases and 192 normal cases. The maxillofacial soft tissue indicators were measured and compared. The A/N ratio and adenoid thickness consistently increased with age in the hypertrophic group and the A/N ratio reached a maximum value three years earlier than the normal group. The pharyngeal airway space, vallecula of epiglottis to anterior plane distance of the third/fourth cervical vertebrae, angle of convexity, total angle of convexity, and the nasolabial angle in the hypertrophy group were smaller than those in the control group (p < 0.05). The thickness of adenoids, palate height, palate length, and tongue length in the hypertrophy group exceeded that of the control group (p < 0.05). To conclude, adenoid hypertrophy was associated with craniofacial features such as a convex facial profile, a narrowed nasopharyngeal airway, an elongated and heightened palate, a lengthened tongue or a lower tongue position. These findings emphasize the importance of early intervention for children with adenoid hypertrophy to mitigate potential adverse effects on maxillofacial development.

Age-related hypertrophy of adenoid and tonsil with its relationship with craniofacial morphology

BACKGROUND

When analyzing the relationship between adenotonsillar hypertrophy and craniofacial morphology, researchers generally regarded hypertrophied adenoids and tonsils as a whole. It remains unclear whether different enlarged sites of pharyngeal lymphoid tissue would correlate with multiple craniofacial subtypes. We hypothesized there would be craniofacial subtypes correlated with different locations of hypertrophied adenoid and tonsil.

METHODS

Lateral cephalometric radiographs were obtained from 466 children (171 boys and 295 girls, aged 12.27 ± 2.69 years). They were divided into four groups according to different sites of enlarged pharyngeal lymphoid tissue: adenoid hypertrophy group (AG, n = 126), tonsillar hypertrophy group (TG, n = 59), adenotonsillar hypertrophy group (ATG, n = 69) and control group (CG, n = 212). Five commonly used angles for cephalometric measurements were investigated: SNA (Sella-Nasion-Point A), SNB (Sella-Nasion-Point B), ANB (Point A-Nasion-Point B), mandibular plane angle (MP/SN) and Y-axis angle (SGn/FH).

RESULTS

Children with isolated tonsillar hypertrophy correlated with increased SNA (unstandardized regression coefficient B = 1.38, p = 0.009) and SNB (B = 1.99, p = 0.001) compared with controls. However, children with isolated adenoid hypertrophy correlated with decreased SNB (B=-0.94, p = 0.036), increased ANB (B = 0.74, p = 0.014) and increased MP/SN (B = 2.22, p < 0.001). Similarly, children with adenotonsillar hypertrophy correlated with decreased SNB (B=-1.36, p = 0.015), increased ANB (B = 1.35, p < 0.001) and increased MP/SN (B = 2.64, p = 0.001).

CONCLUSIONS

Isolated adenoid hypertrophy correlated with a retrognathic mandible, an increased maxillo-mandibular sagittal discrepancy, and an increased mandibular plane angle. Isolated tonsillar hypertrophy correlated with maxillary and mandibular protrusion. Adenotonsillar hypertrophy did not show a superimposed craniofacial pattern of the above two but showed the same craniofacial pattern as isolated adenoid hypertrophy.

The effect of rapid maxillary expansion on the upper airway's aerodynamic characteristics

Background

The effect of rapid maxillary expansion (RME) on the upper airway (UA) has been studied earlier but without a consistent conclusion. This study aims to evaluate the outcome of RME on the UA function in terms of aerodynamic characteristics by applying a computational fluid dynamics (CFD) simulation.

Methods

This retrospective cohort study consists of seventeen cases with two consecutive CBCT scans obtained before (T0) and after (T1) RME. Patients were divided into two groups with respect to patency of the nasopharyngeal airway as expressed in the adenoidal nasopharyngeal ratio (AN): group 1 was comprised of patients with an AN ratio < 0.6 and group 2 encompassing those with an AN ratio ≥ 0.6. CFD simulation at inspiration and expiration were performed based on the three-dimensional (3D) models of the UA segmented from the CBCT images. The aerodynamic characteristics in terms of pressure drop (ΔP), maximum midsagittal velocity (V_ms), and maximum wall shear stress (P_ws) were compared by paired t-test and Wilcoxon test according to the normality test at T0 and T1.

Results

The aerodynamic characteristics in UA revealed no statistically significant difference after RME. The maximum V_ms (m/s) decreased from 2.79 to 2.28 at expiration after RME (P = 0.057).

Conclusion

The aerodynamic characteristics were not significantly changed after RME. Further CFD studies with more cases are warranted.

The efficacy of different treatment approaches for pediatric OSAHS patients with mandibular retrognathia: study protocol for a multicenter randomized controlled trial

Background

Pediatric obstructive sleep apnea/hypopnea syndrome (OSAHS) is a multifactorial syndrome caused by many risk factors, such as craniofacial anomalies, adenotonsillar hypertrophy, obesity, and airway inflammation. Although new treatment patterns have recently been proposed, treatment methods for children remain particularly challenging and controversial. This randomized controlled trial was designed to investigate the efficacy of adenotonsillectomy and/or orthodontic treatment for children who have mild OSAHS with mandibular retrognathia.

Methods

A sample of 352 children with mild OSAHS and mandibular retrognathia, who are aged between 7 and 10 years, will be enrolled in the study. They will be randomized into four groups: the drug treatment group, the surgical treatment group, the orthodontic treatment group, or the surgery and postoperative orthodontic group. After randomization the children will receive treatments within 4 weeks. Outcome assessment will take place at the following points: (1) baseline, (2) 7 months after the treatment starting point, (3) 12 months after the treatment starting point, and (4) 24 months after the treatment starting point. The primary endpoint of the trial is the mean change in obstructive apnea/hypopnea index. Other endpoints will consist of the lowest oxygen saturation, apnea index, and hypopnea index assessed by polysomnography, subjective symptoms (assessed by the OSA-20 questionnaire), cephalometric measurements, and morphologic analysis of the upper airway.

Discussion

The results of this study will provide valuable evidence for the merits and long-term efficacy of different treatment approaches and contribute to facilitating the multidisciplinary treatment of pediatric OSAHS.

Trial registration

ClinicalTrials.gov: NCT03451318. Registered on 2 March 2018 (last update posted 19 April 2018).

Radiographic Evaluation of Sleep-Disordered Breathing

Sleep-disordered breathing and obstructive sleep apnea are becoming more prevalent in today's population. Management of these conditions can be difficult and this diagnosis is often overlooked by clinicians. An increased awareness and understanding of craniofacial structures and anatomic relationships can aid the clinician in identifying at-risk patients, and improve treatment outcomes. An airway review of 3-dimensional computed tomography imaging can identify (1) anatomic variations that contribute to obstructive airway complications, and (2) measurable dimensions to identify at risk patients. This article provides instruction on the key anatomic landmarks and imaging protocols for radiographic airway evaluation.

Craniofacial skeletal pattern: is it really correlated with the degree of adenoid obstruction?

OBJECTIVE

The aim of this study was to compare the cephalometric pattern of children with and without adenoid obstruction.

METHODS

The sample comprised 100 children aged between four and 14 years old, both males and females, subjected to cephalometric examination for sagittal and vertical skeletal analysis. The sample also underwent nasofiberendoscopic examination intended to objectively assess the degree of adenoid obstruction.

RESULTS

The individuals presented tendencies towards vertical craniofacial growth, convex profile and mandibular retrusion. However, there were no differences between obstructive and non-obstructive patients concerning all cephalometric variables. Correlations between skeletal parameters and the percentage of adenoid obstruction were either low or not significant.

CONCLUSIONS

Results suggest that specific craniofacial patterns, such as Class II and hyperdivergency, might not be associated with adenoid hypertrophy.

Dental arch dimensional changes after adenoidectomy or tonsillectomy in children with airway obstruction: A meta-analysis and systematic review under PRISMA guidelines

BACKGROUND

Children with severe airway obstruction tend to have a vertical direction of growth, class II malocclusion, and narrow arches. Adenoidectomy and tonsillectomy were recommended for the promotion of balanced dentition growth in these children.The aim of this study was to determine the effect of adenoidectomy and tonsillectomy on the growth of dental morphology in children with airway obstruction.

METHODS

A comprehensive search of the Medline, Embase, Web of science, and OVID databases for studies published through to January 17, 2016 was conducted. Prospective, comparative, clinical studies assessing the efficacy of adenoidectomy, or tonsillectomy in children with airway obstruction were included. The weighted mean difference (WMD) and 95% confidence interval (CI) were used for continuous variables. Forest plots were drawn to demonstrate effects in the meta-analyses.

RESULTS

Eight papers were included in our study. We found that adenoidectomy and tonsillectomy led to a significant change in nasal-breathing in children with airway obstruction. Children with airway obstruction had a significantly narrower posterior maxillary dental arch than children without airway obstruction (WMD = -0.94, 95% CI [-1.13, -0.76]; P < 0.001). After surgery, these children still had a significantly narrower dental arch than the nasal-breathing children (WMD = -0.60, 95% CI [-0.79, -0.42]; P < 0.001). In terms of dental arch width, malocclusion, palatal height, overjet, overbite, dental arch perimeter, and arch length, a tendency toward normalization was evident following adenoidectomy or tonsillectomy, with no significant differences evident between the surgical group and the normal group. The small number of studies and lack of randomized controlled trials were the main limitations of this meta-analysis.

CONCLUSIONS

Following adenoidectomy and tonsillectomy, the malocclusion and narrow arch width of children with airway obstruction could not be completely reversed. Therefore, other treatments such as functional training or orthodontic maxillary widening should be considered after removing the obstruction in the airway.

Are distinct etiologies of upper airway obstruction in mouth-breathing children associated with different cephalometric patterns?

OBJECTIVE

To test the null hypothesis that mouth-breathing (MB) children by distinct obstructive tissues present a similar cephalometric pattern.

METHODS

The sample included 226 prepubescent children (113 MB and 113 nasal breathing (NB) controls). An ENT clinical examination, including flexible nasal endoscopy, orthodontic clinical and cephalometric examinations, was performed on the MB population. MB children were grouped into three categories, according to the obstructive tissues: 1) adenoid group (AG), 2) tonsillar group (TG), and 3) adenotonsillar group (ATG). The NB controls were matched by gender, age, sagittal dental relationship and skeletal maturation status. Lateral cephalometric radiography provided the cephalometric pattern comparisons between the MB and NB groups.

RESULTS

MB cephalometric measurements were significantly different from those of NB children, exception in the SNB° (P=0.056). All comparisons between the three groups of MB children with the NB children showed a significant difference. Finally, even among the three groups of MB children, a significant difference was observed in the measurements of the SNB° (P<0.036), NSGn° (P<0.028) and PFH/TAFH ratio (posterior facial height/total anterior facial height) (P<0.012).

CONCLUSIONS

The cephalometric pattern of MB and NB children was not similar. Cephalometric measurements of the MB group differed according to the etiology of upper airway obstruction. Children with isolated hypertrophy of the palatine tonsils presented with a mandible that was positioned more forward and upward compared to children obstructed only by the enlarged adenoid.

Cephalometric analysis of craniofacial morphology and growth in unrepaired isolated cleft palate patients

OBJECTIVE

The aim of this study is to analyze the craniofacial morphology in patients with unrepaired isolated cleft palate (UICP) at childhood, adolescence and adulthood, in order to assess the influence of nonsurgical factors on the craniofacial growth in these patients.

MATERIAL AND METHODS

Lateral and posteroanterior cephalograms of 106 non-syndromic UICP patients and 102 normal matched controls were obtained and analyzed. Patients and controls were divided into three subgroups: children (5-7 years), adolescents (12-14 years), and adults (>18 years).

RESULTS

UICP patients in childhood showed a shortened cranial basal length; reduced bony nasopharyngeal height; short maxillary depth and height with a posterior positioned maxilla and an increased width of the nasal cavity, maxilla and orbit; and a shortened mandibular length and height. UICP patients in adulthood showed a normal nasopharyngeal and mandibular morphology. However, the patients in this subgroup still showed a shortened cranial basal length, and short maxillary depth and anterior height with increased width of the nasal cavity, maxilla and orbit.

CONCLUSIONS

Craniofacial morphology and growth in patients with UICP were significantly affected by nonsurgical factors. Growth of the cranial base and upper face were absolutely reduced, while growth of the bony nasopharynx and mandible were only postponed.

Comparisons of soft tissue chin thickness in adult patients with various mandibular divergence patterns

OBJECTIVE

To evaluate the association between soft tissue at the chin (STC) thickness and mandibular divergence.

MATERIALS AND METHODS

Nongrowing patients seeking orthodontic treatment (n  =  190; 113 women and 77 men), who had an average age of 26.94 years (range  =  18.10-53.50 years), were stratified in four subgroups based on cephalometric mandibular plane inclination to anterior cranial base (MP/SN): low  =  MP/SN ≤ 27° (n  =  48); medium-low  =  27° < MP/SN ≤ 32° (n  =  60); medium-high  =  32° < MP/SN < 37° (n  =  37); and high  =  MP/SN ≥ 37° (n  =  45). The STC thicknesses were measured at pogonion (Pog), gnathion (Gn), and menton (Me). Group differences were evaluated with two-way analysis of variance and Student's t-test. The Pearson product moment correlation gauged associations between parameters.

RESULTS

The STC values were greater in men than women (P < .02) and were smaller in the high group (7.47 ± 2.42 mm) than in all other groups at Gn (mean values  =  9.00 mm < STC < 9.58 mm; P < .001) and at Me (high group  =  6.30 ± 1.89 mm; other groups  =  7.15 mm < STC< 7.57 mm; P  =  .011).

CONCLUSION

The STC is thinner at Gn and Me in hyperdivergent facial patterns, apparently in contrast to Pog. This differential thickness warrants focused research as it implies that it is possible (1) to vertically grow hard tissues impinging on the inferior soft tissue envelope in patients with severe hyperdivergence and (2) to plan for genioplasty in such patients when more advancement of the chin might be needed to compensate for the increased vertical height.

Craniofacial morphological characteristics in children with obstructive sleep apnea syndrome: a systematic review and meta-analysis

BACKGROUND

The authors conducted a systematic review to consolidate the current knowledge regarding craniofacial morphological characteristics associated with obstructive sleep apnea syndrome (OSAS) in nonsyndromic pediatric patients.

TYPES OF STUDIES REVIEWED

The authors included clinical studies in which participants were younger than 18 years, polysomnography was performed to determine the presence and severity of OSAS and the study group was compared with a control group or normative growth center data. The authors excluded studies with syndromic participants or participants who had received orthodontic treatment, orthognathic treatment or both previously.

RESULTS

The authors identified nine articles. They conducted a meta-analyses of the data from all but one of the studies to evaluate the eight most common cephalometric variables in children with OSAS. The I(2) values were 79.53 percent for the angle from the basion point to the sella nasion (SN) line, 89.54 percent for the angle between the SN and palatal plane lines and 96.82 percent for the angle between the mandibular plane and SN lines (MP-SN). Therefore, for these three variables, the authors conducted a random-effect model meta-analysis. For the remaining five variables (MP-SN, the angle from SN to Apoint, the angle from SN to B point [SNB], the angle from A point to nasion point to B point [ANB] and the angle from articulare point to gonion point to gnathion point), I(2) values were all less than 40 percent, and therefore the authors conducted a fixed-effects model meta-analysis. Three of the evaluated cephalometric variables (MP-SN, SNB and ANB) had statistically significant differences in comparison with those in a control group. Although the values of these variables were increased in children with OSAS, results of the meta-analysis should be considered cautiously owing to the limited number of cephalometric variables included.

PRACTICAL IMPLICATIONS

Dentists who identify patients with a craniofacial morphology consistent with pediatric OSAS (retrusive chin, steep mandibular plane, vertical direction of growth and a tendency toward Class II malocclusion) should inquire further into their patients' medical histories. When the craniofacial morphology is accompanied by a history of snoring, inability to breathe through the nose, significant allergies, asthma or obesity, the dentist should refer the patient to an otolaryngologist for assessment.