The primary role of functional matrices in facial growth

Morphological Covariation between the Maxillary Sinus and Midfacial Skeleton among Sub-Saharan and Circumpolar Modern Humans

OBJECTIVES

Maxillary sinus volume tracks ecogeographic differences in nasal form and may serve as a zone of accommodation for ontogenetic and evolutionary changes in nasal cavity breadth. However, little is known regarding how sinus volume is distributed within the midface. This study investigates morphological covariation between midfacial and sinus shape to better understand structural and functional relationships between the sinus, midface, and nasal cavity.

METHODS

Cranial and sinus models were rendered from CT scans of modern human samples from two disparate climates: sub-Saharan (South Africans [n = 15], West Africans [n = 17]), and circumpolar (Siberian Buriats [n = 18], Alaskan Inuit [n = 20]). Twenty-five 3D coordinate landmarks were placed on the models and subjected to generalized Procrustes analysis. Two-block partial least squares (2B-PLS) analysis was employed to identify patterns of covariation.

RESULTS

The 2B-PLS analysis indicates PLS1 (58.6% total covariation) relates to height and breadth relationships between the midface, nasal cavity, and maxillary sinus. Significant regional differences in PLS1 scores are evident: circumpolar samples possess taller/narrower noses with taller/wider sinuses compared to sub-Saharan samples. Importantly, PLS1 indicates that sinus breadth is not exclusively related to nasal cavity breadth; variation in lateral sinus expansion toward the zygoma represents an important contributing factor. PLS2 (16%) relates to supero-inferior positioning of the sinus within the midface. Allometric trends, while statistically significant, explain only a small portion of these covariation patterns.

CONCLUSIONS

These results suggest that the maxillary sinus serves as a zone of accommodation at the confluence of multiple facial components, potentially minimizing effects of morphological alterations to certain components on adjacent structures. Am J Phys Anthropol 160:483-497, 2016. © 2016 Wiley Periodicals, Inc.

Conservative gap arthroplasty in temporomandibular ankylosis not involving the sigmoid notch: a selected age group study

In this prospective, cohort, clinical follow-up study we aimed to investigate the role of conservative gap arthroplasty without interpositional material in managing ankylosis of the temporomandibular joint (TMJ). Thirteen patients (15 joints) with ankylosis who fulfilled the other inclusion criteria were enrolled. The ankylotic mass was excised to create a gap of 7-9mm. No interpositional material was used. Ipsilateral or bilateral masseter reflection, pterygomasseteric sling, and temporalis tendon release plus coronoidectomy were considered if maximum mouth opening failed to reach 35mm. A physiotherapy protocol was started on the first day. Patients' ages ranged from 13-38 (mean (SD) 18 (7) years). Trauma was the main cause. Duration of ankylosis at presentation ranged from 1-17 years (mean (SD) 5 (4) years). Eleven patients had unilateral, and two bilateral, ankylosis that did not involve the sigmoid notch. The mean (SD) maximum incisal opening (mm) was 38 (4) two years' postoperatively. The facial nerve was affected temporarily in two patients. Mean (SD) duration of follow-up was 4 (2) years without recurrence. Within our selection criteria, conservative gap arthroplasty of 7-9mm without interpositional material and with vigorous postoperative physiotherapy has a role in treating ankylosis of the TMJ and preventing its recurrence for more than four years.

Tongue pressure production during swallowing in patients with mandibular prognathism

Abnormalities of swallowing in patients with mandibular prognathism have not been evaluated quantitatively. The aim of this study was to compare tongue pressure production for bolus transfer between volunteers with normal occlusion and patients with mandibular prognathism. The control group had 10 female volunteers with normal occlusion, and the patient group had 10 women with mandibular prognathism. Tongue pressure was measured by a palatal sensor sheet at five sites on swallowing 4 mL of a tasteless and odourless jelly.

RESULTS

The tongue pressure waveform differed between the control and patient groups. The incidence of a double-peak tongue pressure waveform was more frequent in the patient group. In both groups, the exertion of tongue pressure began at the anterior point of the sensor sheet, followed by the peripheral parts. Although the order of expression of tongue pressure was the same for the two groups, maximum tongue pressure at all parts of the sensor sheet was lower in the patient group than in the control group. Furthermore, swallowing time was longer in the patient group than in the control group at the peripheral parts of the palate. These results clearly show the difference in tongue pressure production during swallowing between patients with mandibular prognathism and volunteers with normal occlusion. The current findings suggest that maxillofacial morphology may affect tongue movement during swallowing.

WITHDRAWN: Orthodontics for treating temporomandibular joint (TMJ) disorders

The Cochrane Oral Health Group withdrew this review as of Issue 1, 2016. The review is out of date and does not meet current Cochrane methodological standards. It will be superseded by a new Cochrane review on Occlusal interventions for managing temporomandibular disorders.

The editorial group responsible for this previously published document have withdrawn it from publication.

Long-term results of remodelling the facial bones with a soft moulding helmet in beagles: the "reciprocally stimulated growth" hypothesis

Facial deformity is often seen in infants with deformational plagiocephaly and it usually improves with conservative management. However, we know of few studies of the effect of helmet treatment on the facial skeleton. Our aim therefore was to find out its long-term effects on skull remodelling, and on the shape of the face. Seven beagles wore helmets for seven weeks after birth. Seven study beagles and 3 controls were killed and we measured the length, width, and height of the skulls, maxillas, and mandibles. Statistical analysis showed that the total craniofacial length and skull length did not differ significantly, and skull volumes were similar. Maximal craniofacial, skull, maxillary, and mandibular width were all significantly less in the study group. The maximal craniofacial, maxillary, and mandibular widths were strongly correlated with changes in the skull width, and the width:length ratios of the skulls, maxillas, and mandibles did differ significantly. The skull widths in the study group were significantly smaller, which suggests that a soft moulding helmet may change the growth pattern permanently. The effect of a soft moulding helmet on the lateral aspect of the skull affected the width of the face semipermanently. This modulation in the shape of the skull vault and base may change the shape of the maxilla and mandible, which may serve as a background for the use of helmet treatment to change the facial configuration.

Skeletal effects of the alteration of masseter muscle function

Aim

To investigate the effects of muscle denervation and the introduction of the β2-adrenoceptor agonist, formoterol, on the relationship between muscles and underlying skeletal growth.

Method

Thirty-one (4-week-old) male Sprague-Dawley rats were assigned to four groups: Surgical Sham; Denervated; Denervated +β2-agonist; and β2-agonist only. The Surgical Sham group had the left masseteric nerve exposed but not sectioned. Both of the denervated groups had the left masseteric nerve exposed and sectioned. The groups receiving the β2-agonist had formoterol directly injected into the left masseter muscle every three days for eight weeks. Sixteen angular and linear skeletal measurements were assessed in the overall craniofacial region and the mandible via standardised digital radiography in three views: lateral head, submento-vertex and right and left disarticulated hemi-mandibles.

Results

The findings indicated that, following surgical denervation of the masseter muscle, there were significant changes in the muscle and in the subsequent development of the underlying skeletal structures. The post-surgical changes were largely offset by the administration of a β2-agonist, formoterol, which attenuated muscle atrophy. However, the administration of the β2-agonist only, without surgical denervation, did not lead to changes in skeletal facial form.

Conclusions

Denervation atrophy of the masseter muscle results in statistically significant changes in the development of the underlying skeleton. The changes, however, are localised to areas of muscle attachment. The administration of the β2-agonist, formoterol, despite its effect on muscle anabolism, does not have a significant effect on underlying skeletal growth.

Heritability of mandibular cephalometric variables in twins with completed craniofacial growth

OBJECTIVES

To determine genetic and environmental impact on mandibular morphology using lateral cephalometric analysis of twins with completed mandibular growth and deoxyribonucleic acid (DNA) based zygosity determination.

MATERIALS AND METHODS

The 39 cephalometric variables of 141 same gender adult pair of twins were analysed. Zygosity was determined using 15 specific DNA markers and cervical vertebral maturation method was used to assess completion of the mandibular growth. A genetic analysis was performed using maximum likelihood genetic structural equation modelling (GSEM).

RESULTS

The genetic heritability estimates of angular variables describing horizontal mandibular position in relationship to cranial base and maxilla were considerably higher than in those describing vertical position. The mandibular skeletal cephalometric variables also showed high heritability estimates with angular measurements being considerably higher than linear ones. Results of this study indicate that the angular measurements representing mandibular skeletal morphology (mandibular form) have greater genetic determination than the linear measurements (mandibular size).

CONCLUSIONS

The shape and sagittal position of the mandible is under stronger genetic control, than is its size and vertical relationship to cranial base.

Distinct growth of the nasomaxillary complex in Au. sediba

Studies of facial ontogeny in immature hominins have contributed significantly to understanding the evolution of human growth and development. The recently discovered hominin species Autralopithecus sediba is represented by a well-preserved and nearly complete facial skeleton of a juvenile (MH1) which shows a derived facial anatomy. We examined MH1 using high radiation synchrotron to interpret features of the oronasal complex pertinent to facial growth. We also analyzed bone surface microanatomy to identify and map fields of bone deposition and bone resorption, which affect the development of the facial skeleton. The oronasal anatomy (premaxilla-palate-vomer architecture) is similar to other Australopithecus species. However surface growth remodeling of the midface (nasomaxillary complex) differs markedly from Australopithecus, Paranthropus, early Homo and from KNM-WT 15000 (H. erectus/ergaster) showing a distinct distribution of vertically disposed alternating depository and resorptive fields in relation to anterior dental roots and the subnasal region. The ontogeny of the MH1 midface superficially resembles some H. sapiens in the distribution of remodeling fields. The facial growth of MH1 appears unique among early hominins representing an evolutionary modification in facial ontogeny at 1.9 my, or to changes in masticatory system loading associated with diet.

Anatomical Network Comparison of Human Upper and Lower, Newborn and Adult, and Normal and Abnormal Limbs, with Notes on Development, Pathology and Limb Serial Homology vs. Homoplasy

How do the various anatomical parts (modules) of the animal body evolve into very different integrated forms (integration) yet still function properly without decreasing the individual's survival? This long-standing question remains unanswered for multiple reasons, including lack of consensus about conceptual definitions and approaches, as well as a reasonable bias toward the study of hard tissues over soft tissues. A major difficulty concerns the non-trivial technical hurdles of addressing this problem, specifically the lack of quantitative tools to quantify and compare variation across multiple disparate anatomical parts and tissue types. In this paper we apply for the first time a powerful new quantitative tool, Anatomical Network Analysis (AnNA), to examine and compare in detail the musculoskeletal modularity and integration of normal and abnormal human upper and lower limbs. In contrast to other morphological methods, the strength of AnNA is that it allows efficient and direct empirical comparisons among body parts with even vastly different architectures (e.g. upper and lower limbs) and diverse or complex tissue composition (e.g. bones, cartilages and muscles), by quantifying the spatial organization of these parts-their topological patterns relative to each other-using tools borrowed from network theory. Our results reveal similarities between the skeletal networks of the normal newborn/adult upper limb vs. lower limb, with exception to the shoulder vs. pelvis. However, when muscles are included, the overall musculoskeletal network organization of the upper limb is strikingly different from that of the lower limb, particularly that of the more proximal structures of each limb. Importantly, the obtained data provide further evidence to be added to the vast amount of paleontological, gross anatomical, developmental, molecular and embryological data recently obtained that contradicts the long-standing dogma that the upper and lower limbs are serial homologues. In addition, the AnNA of the limbs of a trisomy 18 human fetus strongly supports Pere Alberch's ill-named "logic of monsters" hypothesis, and contradicts the commonly accepted idea that birth defects often lead to lower integration (i.e. more parcellation) of anatomical structures.

The relationship between occlusal support and maxillary development: An animal study

Objective:

To test the hypothesis that maxillary development may be affected by occlusal support.

Materials and Methods:

The sample was composed by Wistar rats (5 weeks old) divided into three groups: Control (n = 10), extraction of mandibular molar teeth – left side (n = 10), extraction mandibular molar teeth – left and right sides (n = 10). The rats were sacrificed 8 weeks postextraction. Cone beam computed tomography scan images were taken for posterior measurement of maxillary length and width. Data were analyzed by one-way analysis of variance (Tukey test as post-hoc test).

Results:

Maxillary length was significantly shorter (P < 0.005) in both groups after tooth extraction. No difference was observed regarding maxillary width and body weight.

Conclusion:

Reduced occlusal support may impair the development of the maxilla in rats.

Modified functional obturator for the consideration of facial growth in the mucoepidermoid carcinoma pediatric patient

Mucoepidermoid carcinoma (MEC) is a common salivary gland tumor in a adults but is very rare in pediatric patients. The standard treatment of MEC is en bloc resection with wide safety margins and subsequent reconstruction of the jaw, but few surgeons or pediatric specialists have experience with this procedure. An 11-year-old boy received a hemi-maxillectomy with subsequent application of the modified functional obturator (MFO) by the functional matrix concept of Moss. And the patient's face showed normal growth pattern. The purpose of this report is to demonstrate the novel concept of pediatric maxillary reconstruction using MFO for the consideration of facial growth.

[Influence of trigeminal nerve lesion on facial growth: study of two cases of Goldenhar syndrome]

INTRODUCTION

This cases report confirms the hypothesis that embryonic and maxillofacial growth are influenced by the peripheral nervous system, including the trigeminal nerve (V). So, it's interesting to use the stigma of the trigeminal nerve as landmarks to analyze the maxillofacial volume and understand its growth. The aim of this study is to evaluate the validity of the three-dimensional cephalometric analysis of Treil based on trigeminal landmarks.

CASE PRESENTATION

The first case is a caucasian female child with Goldenhar syndrome. The second case is a caucasian male adult affected by the same syndrome. In both cases, brain MRI showed an unilateral trigeminal nerve lesion, ipsilateral to the facial dysmorphia.

CONCLUSION

The results of this radiological study tend to prove the primary role of the trigeminal nerve in craniofacial growth. These cases demonstrate the validity of the theory of Moss. They are one of anatomo-functional justifications of the three-dimensional cephalometric biometry of Treil based on trigeminal nerve landmarks.

A comparative evaluation of dermatoglyphics in different classes of malocclusion

Aim

To study associations of dermatoglyphic features with malocclusion in Indian children.

Materials and methods

A total of 237 children aged 12–16 years, who attended our outpatient clinic in a government medical college, were selected. Finger and palm prints were collected, and fingertip pattern frequencies, total ridge counts (TRCs), and atd angles (formed by the triradii below the first and last digits and that in the hypothenar region of the palm) were calculated. These parameters were analyzed with their Angle’s class of malocclusion using appropriate statistical tests. Dermatoglyphic parameters were examined and asymmetry analysis was conducted in subjects with different occlusion patterns.

Results

Although no fingerprint pattern was found to be specific for a particular class of occlusion, increased tendencies toward high frequencies of whorls in subjects with class II malocclusion and plain arches in those with class III malocclusion were observed. Significant differences in atd angle and TRC were observed among malocclusion types (p = 0.0001). Asymmetry scores did not differ significantly.

Conclusion

Dermatoglyphic analysis can be used as an indicator of malocclusion at an early age, thereby aiding the development of treatments aiming to establish favorable occlusion. Inheritance and twin studies, as well as those conducted in different ethnic groups, are required to examine these relationships further.

Dental treatment for paediatric obstructive sleep apnea

Paediatric obstructive sleep apnea (OSA) is common and its prevalence is expected to increase due to the rise in childhood obesity. Recent research has shown that many children, both syndromic and non-syndromic, who exhibit mouth breathing as a result of upper airway obstruction, may also exhibit dentofacial anomalies. Although adenotonsillectomy and continuous positive airway pressure have been classically proposed as the primary treatment modalities for paediatric OSA, there are significant limitations to both therapies. Therefore newer treatment modalities are needed. Current research has focused on emerging dental treatment options for paediatric OSA, such as rapid maxillary expansion, oral appliances and distraction osteogenesis. However, there are few randomized trials assessing the effectiveness of these novel dental therapies for paediatric OSA, and hence further research is required to advance the field.

Função respiratória em indivíduos com deformidades dentofaciais

OBJETIVO: caracterizar a função respiratória de indivíduos com deformidade dentofacia em relação às vias aéreas superiores e inferiores e ao aspecto da respiração voltado à fonação. MÉTODOS: 40 indivíduos adultos, divididos em três grupos: grupo controle, deformidade dentofacial II e deformidade dentofacial III, estando os dois últimos em tratamento ortodôntico para cirurgia ortognática. Realizado exame clínico do Protocolo MBGR para tipo e modo respiratório, fluxo aéreo nasal, possibilidade de uso nasal e obtenção do escore do protocolo; espirometria para avaliação da capacidade respiratória; fluxo aéreo expiratório utilizando espelho milimetrado para cálculo da área de embaçamento e medida do tempo de fonação de /s/. RESULTADOS: observou-se maior ocorrência do tipo respiratório médio superior para todos os grupos. Houve diferença estatística para modo respiratório, sendo a maioria dos participantes com deformidade dentofacial respiradores oronasais ou orais; no fluxo expiratório nasal, os indivíduos com deformidade dentofacial apresentaram fluxo reduzido unilateralmente; na possibilidade de uso nasal, o grupo deformidade dentofacial II teve maior número de indivíduos com prejuízo; no escore, o grupo deformidade dentofacial II apresentou os piores resultados. Indivíduos com menor possibilidade de uso nasal apresentaram menor área de embaçamento do espelho e menor tempo fonatório de /s/. Para os respiradores orais foi encontrado menor tempo fonatório de /s/. A análise estatística não evidenciou diferença entre os grupos nos exames objetivos. CONCLUSÕES: indivíduos com deformidade dentofacial apresentaram tipo respiratório médio superior, modo oral ou oronasal, reduzidos fluxo expiratório nasal e suporte respiratório para a fonação, sendo que prejuízos na possibilidade do uso nasal e a presença de respiração oral influenciaram a utilização do ar expiratório para a fala.

Association between facial growth pattern and facial muscle activity: A prospective cross-sectional study

OBJECTIVE

To evaluate the relationship between facial growth pattern and electromyography (EMG) of facial muscles: anterior temporalis, masseter, buccinators, orbicularis oris, mentalis and anterior digastric.

PATIENTS AND METHODS

The sample consisted of 77 subjects aged between 18-28 years (mean age 21.10±2.03), with dental Class I relationship, normal overjet and overbite, balanced facial profile, no signs of temporomandibular disorders, and no previous orthodontic treatment. Facial growth pattern was determined on the lateral cephalograms according to the Björk sum (sum of the N-S-Ar, S-Ar-Go, and Ar-Go-Me angles) dividing the sample into three groups: horizontal facial pattern group (24 subjects), normal facial pattern group (41 subjects), and vertical facial pattern group (12 subjects). The EMG of anterior temporalis, masseter, buccinator, orbicularis oris, mentalis and anterior digastric muscles were examined for each patient in the rest position and in functional positions (central maximum intercuspation, chewing on right side, chewing on left side and swallowing). Mean values and standard deviation of EMG were obtained and compared between the three groups.

RESULTS

At rest, the EMG of the masseter, orbicularis oris and anterior digastric were higher in the vertical facial pattern group compared with the other two groups, with a moderate positive correlation between the EMG of these muscles and the Björk sum (P<.01). In contrast, during central maximum intercuspation, the activity of the anterior temporalis, masseter and buccinator was significantly lower in the vertical facial pattern group compared with the two other groups, with a moderate negative correlation between the Björk sum and EMG in the maximum central intercuspation position of these muscles (P<.01).

CONCLUSIONS

A significant relationship was found between facial muscle activity and facial growth pattern. The findings suggest that the activity of masticatory and perioral muscles could play a role in the direction of the facial growth.

Development of the nasolacrimal apparatus in the Mongolian gerbil (Meriones unguiculatus), with notes on network topology and function

The nasolacrimal apparatus (NLA) is a multicomponent functional system comprised of multiple orbital glands (up to four larger multicellular exocrine structures), a nasal chemosensory structure (vomeronasal organ: VNO), and a connecting duct (nasolacrimal duct: NLD). Although this system has been described in all tetrapod vertebrate lineages, albeit not always with all three main components present, considerably less is known about its ontogeny. The Mongolian gerbil (Meriones unguiculatus) is a common lab rodent in which the individual components of the adult NLA have been well studied, but as yet nothing is known about the ontogeny of the NLA. In this study, serial sections of 15 fetal and three adult Mongolian gerbil heads show that the development of the NLA falls into three fetal stages: inception (origin of all features), elongation (lengthening of all features), and expansion (widening of all features). No postnatal or juvenile specimens were observed in this study, but considerable growth evidently occurs before the final adult condition is reached. The development of the orbital glands and the VNO in the Mongolian gerbil is largely consistent with those in other mammals, despite a slight nomenclatural conundrum for the anterior orbital glands. However, the Mongolian gerbil NLD follows a more circuitous route than in other tetrapods, due mainly to the convoluted arrangement of the narial cartilages, the development of a pair of enlarged incisors as well as an enlarged infraorbital foramen. The impact of these associated features on the ontogeny and phylogeny of the NLA could be examined through the approach of network science. This approach allows for the incorporation of adaptations to specific lifestyles as potential explanations for the variation observed in the NLA across different tetrapod clades.

Geographic Variation in Zygomaxillary Suture Morphology and its Use in Ancestry Estimation

Angled/curved zygomaxillary suture coding is widely employed in cranial assessments of ancestry. However, the efficacy of this method has not been extensively evaluated across diverse populations. In this study, zygomaxillary suture morphology was assessed on a total of 411 human crania from six populations (European, Native American, African, Asian, Arctic Circle, and Aboriginal Australian) using a novel 3D coordinate landmark method. Our results indicate a predominance of angled sutures among native peoples of the Arctic and North America (85-86%), a prevalence of curved sutures among Africans and Aboriginal Australians (77-81%), and essentially equal proportions of both configurations in Asians and Europeans (50-56%). Statistically, angled/curved coding generally discriminates poorly between groups, except when populations with antithetically high frequencies of the two configurations (e.g., African vs. Native American) are compared. Moreover, comparisons across previous studies reveal conflicting frequencies for many populations, further suggesting limited utility of this trait in ancestry estimation.

Anatomical networks reveal the musculoskeletal modularity of the human head

Mosaic evolution is a key mechanism that promotes robustness and evolvability in living beings. For the human head, to have a modular organization would imply that each phenotypic module could grow and function semi-independently. Delimiting the boundaries of head modules, and even assessing their existence, is essential to understand human evolution. Here we provide the first study of the human head using anatomical network analysis (AnNA), offering the most complete overview of the modularity of the head to date. Our analysis integrates the many biological dependences that tie hard and soft tissues together, arising as a consequence of development, growth, stresses and loads, and motion. We created an anatomical network model of the human head, where nodes represent anatomical units and links represent their physical articulations. The analysis of the human head network uncovers the presence of 10 musculoskeletal modules, deep-rooted in these biological dependences, of developmental and evolutionary significance. In sum, this study uncovers new anatomical and functional modules of the human head using a novel quantitative method that enables a more comprehensive understanding of the evolutionary anatomy of our lineage, including the evolution of facial expression and facial asymmetry.

The relationship between molar bite force and incisor inclination: a prospective cross-sectional study

OBJECTIVE

To examine the relationship between molar bite force (MBF) and both the upper and lower axis inclination of the incisors.

MATERIALS AND METHODS

The sample consisted of 51 participants aged between 18-27 years (mean age: 21.04±2.03), with normal occlusion and a skeletal Class I relationship, no sign of temporomandibular disorders, and no previous orthodontic treatment. Lateral cephalograms were taken and traced and the following measurements were identified: upper incisor angle (U1:SN), lower incisor angle (L1:GoMe), and the interincisal angle (U1:L1). Three sets of groups were established according to the three previously mentioned measurements (G1: decreased; G2: normal; and G3: increased). MBF was measured using a specific sensor that is sensitive to the pressure. Patients were asked to bite in the central occlusion, chew, then swallow the saliva. The mean values and standard deviation of MBF were obtained in each position and in every group then compared between related groups using the independent sample t-test.

RESULTS

MBF values were significantly lower in the decreased upper incisor angle group during chewing at each side than in the normal (P=0.02 right, 0.01 left) and increased (P=0.03 right, 0.02 left) groups,while higher in the increased lower incisor group compared with the normal group (P=0.01) during chewing at the right side. In addition, there was a significant positive correlation between the upper incisor axis and MBF values both in central maximum clenching and chewing. Moreover, there was a positive correlation between the MBF and lower incisor axis during chewing, whereas a negative correlation between the MBF and interincisal angle was detected during chewing and swallowing.

CONCLUSIONS

There was a linear relationship between the MBF and incisor axis. The MBF was higher when both the upper and lower inclination of incisors increased.

Association between breastfeeding duration, non-nutritive sucking habits and dental arch dimensions in deciduous dentition: a cross-sectional study

BACKGROUND

This cross-sectional retrospective study was conducted to determine association between breastfeeding duration, non-nutritive sucking habits, dental arch transverse diameters, posterior crossbite and anterior open bite in deciduous dentition.

METHODS

415 children (228 males and 187 females), 4 to 6 years old, from a mixed Indian population were clinically examined. Based on written questionnaire answered by parents, children were divided into two groups: group 1 (breastfed for <6 months (n = 158)) and group 2 (breastfed for ≥6 months (n = 257)). The associations were analysed using chi-square test (P < 0.05 taken as statistically significant). Odds ratio (OR) was calculated to determine the strength of associations tested. Multivariate logistic regression analysis was done for obtaining independent predictors of posterior crossbite and maxillary and mandibular IMD (Inter-molar distance) and ICD (Inter-canine distance).

RESULTS

Non-nutritive sucking (NNS) was present in 15.18% children (20.3% in group 1 as compared to 12.1% in group 2 (P = 0.024)). The average ICD and IMD in maxilla and average IMD in mandible were significantly higher among group 2 as compared to group 1 (P < 0.01). In mandible, average ICD did not differ significantly between the two groups (P = 0.342). The distribution of anterior open bite did not differ significantly between the two groups (P = 0.865). The distribution of posterior crossbite was significantly different between the two groups (P = 0.001). OR assessment (OR = 1.852) revealed that group 1 had almost twofold higher prevalence of NNS habits than group 2. Multivariate logistic regression analysis revealed that the first group had independently fourfold increased risk of developing crossbite compared to the second group (OR = 4.3). Multivariate linear regression analysis also revealed that age and breastfeeding duration were the most significant determinants of ICD and IMD.

CONCLUSIONS

An increased prevalence of NNS in the first group suggests that NNS is a dominant variable in the association between breastfeeding duration and reduced intra-arch transverse diameters which leads to increased prevalence of posterior crossbites as seen in our study. Mandibular inter-canine width is however unaffected due to a lowered tongue posture seen in these children.

Morphologic variability of nonsyndromic operated patients affected by cleft lip and palate: a geometric morphometric study

INTRODUCTION

In this study, we compared patterns of morphologic variations of the craniofacial skeleton between patients affected by clefts who were operated on and unaffected subjects, aiming to discuss possible morpho-functional consequences of treatment in craniofacial development.

METHODS

The lateral cephalograms of 76 subjects, comprising patients with operated unilateral cleft lip and palate (OpC) and a group matched for sex and age without cleft, were used. Thirteen landmarks were used as variables in geometric morphometric tests quantifying and describing overall shape variation, differences between group means, allometry, and upper-lower face covariation.

RESULTS

The OpC group showed broader shape variations including noncleft group characteristics, but mainly a retrognathic maxilla, a vertically elongated face, a more open mandibular angle, and a more closed basicranial angle. Group means differed mainly in the maxillomandibular relationships. Allometry differed between groups, with the smallest OpC patients showing the most altered morphology. Upper and lower face covariation was stronger in the OpC group, showing mainly vertical changes in the anterior face.

CONCLUSIONS

Operated patients affected by clefts achieve a broad range of morphologies; the most altered were found in those with skeletal Class III and small size. Furthermore, their strongest upper and lower face shape covariation suggests that a harmonic dental occlusion could be a key factor in achieving "normal" craniofacial morphology.

Beyond the functional matrix hypothesis: a network null model of human skull growth for the formation of bone articulations

Craniofacial sutures and synchondroses form the boundaries among bones in the human skull, providing functional, developmental and evolutionary information. Bone articulations in the skull arise due to interactions between genetic regulatory mechanisms and epigenetic factors such as functional matrices (soft tissues and cranial cavities), which mediate bone growth. These matrices are largely acknowledged for their influence on shaping the bones of the skull; however, it is not fully understood to what extent functional matrices mediate the formation of bone articulations. Aiming to identify whether or not functional matrices are key developmental factors guiding the formation of bone articulations, we have built a network null model of the skull that simulates unconstrained bone growth. This null model predicts bone articulations that arise due to a process of bone growth that is uniform in rate, direction and timing. By comparing predicted articulations with the actual bone articulations of the human skull, we have identified which boundaries specifically need the presence of functional matrices for their formation. We show that functional matrices are necessary to connect facial bones, whereas an unconstrained bone growth is sufficient to connect non-facial bones. This finding challenges the role of the brain in the formation of boundaries between bones in the braincase without neglecting its effect on skull shape. Ultimately, our null model suggests where to look for modified developmental mechanisms promoting changes in bone growth patterns that could affect the development and evolution of the head skeleton.

Effect of chin-cup treatment on the temporomandibular joint: a systematic review

AIM

To systematically search the literature and assess the available evidence for the influence of chin-cup therapy on the temporomandibular joint regarding morphological adaptations and appearance of temporomandibular disorders (TMD).

MATERIALS AND METHODS

Electronic database searches of published and unpublished literature were performed. The following electronic databases with no language and publication date restrictions were searched: MEDLINE (via Ovid and PubMed), EMBASE (via Ovid), the Cochrane Oral Health Group's Trials Register, and CENTRAL. Unpublished literature was searched on ClinicalTrials.gov, the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database. The reference lists of all eligible studies were checked for additional studies. Two review authors performed data extraction independently and in duplicate using data collection forms. Disagreements were resolved by discussion or the involvement of an arbiter.

RESULTS

From the 209 articles identified, 55 papers were considered eligible for inclusion in the review. Following the full text reading stage, 12 studies qualified for the final review analysis. No randomized clinical trial was identified. Eight of the included studies were of prospective and four of retrospective design. All studies were assessed for their quality and graded eventually from low to medium level of evidence. Based on the reported evidence, chin-cup therapy affects the condylar growth pattern, even though two studies reported no significance changes in disc position and arthrosis configuration. Concerning the incidence of TMD, it can be concluded from the available evidence that chin-cup therapy constitutes no risk factor for TMD.

CONCLUSION

Based on the available evidence, chin-cup therapy for Class III orthodontic anomaly seems to induce craniofacial adaptations. Nevertheless, there are insufficient or low-quality data in the orthodontic literature to allow the formulation of clear statements regarding the influence of chin-cup treatment on the temporomandibular joint.

The relationship between the cranial base and jaw base in a Chinese population

Introduction

The cranial base plays an important role in determining how the mandible and maxilla relate to each other. This study assessed the relationship between the cranial base and jaw base in a Chinese population.

Methods

This study involved 83 subjects (male: 27; female: 56; age: 18.4 ± 4.2 SD years) from Hong Kong, who were classified into 3 sagittal discrepancy groups on the basis of their ANB angle. A cephalometric analysis of the angular and linear measurements of their cranial and jaw bases was carried out. The morphological characteristics of the cranial and jaw bases in the three groups were compared and assessments were made as to whether a relationship existed between the cranial base and the jaw base discrepancy.

Results

Significant differences were found in the cranial base angles of the three groups. Skeletal Class II cases presented with a larger NSBa, whereas skeletal Class III cases presented with a smaller NSBa (P < 0.001). In the linear measurement, skeletal Class III cases presented with a shorter NBa than skeletal Class I and II cases (P < 0.01). There was a correlation between the cranial base angle NSBa and the SNB for the whole sample, (r = -0.523, P < 0.001). Furthermore, correlations between SBaFH and Wits (r = -0.594, P < 0.001) and SBaFH and maxillary length (r = -0.616, P < 0.001) were more obvious in the skeletal Class III cases.

Conclusions

The cranial base appears to have a certain correlation with the jaw base relationship in a southern Chinese population. The correlation between cranial base and jaw base tends to be closer in skeletal Class III cases.

Articulation error of children with adenoid hypertrophy

PURPOSE

Adenoid hypertrophy is a physical alteration that may affect speech, and a speech disorder can have other negative effects on a child's life. Airway obstruction leads to constricted oral breathing and causes postural alterations of several oro-facial structures, including the mouth, tongue, and hyoid bone. The postural modifications may affect several aspects of speech production.

METHODS

In this study, we compared articulation errors in 19 children with adenoid hypertrophy (subject group) to those of 33 children with functional articulation disorders independent of anatomical problems (control group).

RESULTS

The mean age of the subject group was significantly higher (P=0.016). Substitution was more frequent in the subject group (P=0.003; odds ratio [OR], 1.80; 95% confidence interval [CI], 1.23-2.62), while omission was less frequent (P<0.001; OR, 0.43; 95% CI, 0.27-0.67). Articulation errors were significantly less frequent in the palatal affricative in the subject group (P=0.047; OR, 0.25; 95% CI, 0.07-0.92). The number of articulation errors in other consonants was not different between the two groups. Nasalization and aspiration were significantly more frequent in the subject group (P=0.007 and 0.014; OR, 14.77 and 0.014; 95% CI, [1.62-135.04] and NA, respectively). Otherwise, there were no differences between the two groups.

CONCLUSION

We identified the characteristics of articulation errors in children with adenoid hypertrophy, but our data did not show the relationship between adenoid hypertrophy and oral motor function that has been observed in previous studies. The association between adenoid hypertrophy and oral motor function remains doubtful.

Possible causal relationships between competitive swimming in growing age and three-dimensional dentoalveolar development

Background

The aim of this study was to investigate possible links between competitive swimming during the growth phase and the development of the dentoalveolar arches.

Methods

The study sample included 100 swimmers and a control group of 100 age-matched non-swimmers who had never practised swimming or related sports. Subjects who had had previous orthodontic treatment were excluded. Overjet, overbite, sagittal and transverse parameters, arch dimension, crowding and oral habits were recorded.

Results

In the swimmers, there was a significantly higher frequency of molar symmetry (P = 0.04), together with a greater number of Class I subjects. The overjet in the swimmers was mainly normal, but the arch dimensions were significantly wider (+10% in the upper arch; P < 0.001). Similarly, the swimmers showed significantly less severe crowding (P < 0.001) and significantly reduced oral habits (P < 0.001).

Conclusions

Our data and analysis demonstrate that competitive swimming during the growth phase has a favourable effect on dental arch development in the sagittal, vertical and transverse planes.

Skeletal and dental characteristics in subjects with ankyloglossia

Background

The role of ankyloglossia in etiology of malocclusion is not much discussed over the years. The aim of the present study was to assess the skeletal and dental characteristics in subjects with ankyloglossia.

Methods

Fifty-seven subjects diagnosed with ankyloglossia (group 1) were compared with 60 subjects (group 2) without ankyloglossia, who had class I skeletal base. Ankyloglossia was diagnosed and graded (mild, moderate, severe and very severe) using Kortlow's method. SNA, SNB, ANB, Go-Gn-SN angle, FMA, maxillary and mandibular intercanine widths and intermolar widths, tooth size-arch length discrepancy in maxillary and mandibular arches and overbite were measured. Independent t test was used to compare the mean parameters between the two groups. Analysis of variance and Tukey honestly significant difference were used to compare mean parameters among various grades of ankyloglossia.

Results

Majority of group 1 subjects belonged to class I skeletal base followed by class II and class III skeletal bases. Moderate ankyloglossia was most common in group 1. The mean maxillary and mandibular intercanine widths and maxillary intermolar width were statistically significant in independent t test (P < 0.01) and reduced in group 1. In ANOVA followed by Tukey HS, the Go-Gn-SN angle and overbite were statistically significant among different grades of ankyloglossia (P < 0.05).

Conclusions

Subjects with ankyloglossia had reduced maxillary and mandibular intercanine widths and reduced maxillary intermolar width. The mandibular plane angle and overbite were altered with severity of ankyloglossia.

Morphologic relationship between the cranial base and the mandible in patients with facial asymmetry and mandibular prognathism

INTRODUCTION

This study was conducted to measure the dimensional changes in the cranial base and the mandible in patients with facial asymmetry and mandibular prognathism, and to examine the morphologic relationship between asymmetries of the cranial base and the mandible.

METHODS

The patients were 60 adults with mandibular prognathism, divided into a symmetry group (menton deviation, <2 mm; n = 30) and an asymmetry group (menton deviation, >4 mm; n = 30) according to the degree of menton deviation. Three-dimensional computed tomography scans were obtained with a spiral scanner. Landmarks were designated on the reconstructed 3-dimensional surface models. Linear, angular, and volumetric measurements of the cranial base and mandibular variables were made.

RESULTS

In the asymmetry group, the hemi-base, anterior cranial base, and middle cranial base volumes were significantly larger (P <0.01), and crista galli to sphenoid, sphenoid to petrous ridge, anterior clinoid process to petrous ridge, and vomer to petrous ridge lengths were significantly longer (P <0.05) on the nondeviated side than on the deviated side. Menton deviation was significantly correlated with the difference in hemi-base volume, and ramal volume was significantly correlated with the difference in hemi-base and middle cranial base volumes between the nondeviated and deviated sides (P <0.05).

CONCLUSIONS

In patients with facial asymmetry and mandibular prognathism, cranial base volume increased on the nondeviated side and was also correlated with mandibular asymmetry.

Outcome assessment of 603 cases of concomitant inferior turbinectomy and Le Fort I osteotomy

This retrospective study assessed the outcome of 603 patients undergoing partial inferior turbinectomies (PIT) in association with Lefort I osteotomy. The study included 1234 patients from a single private practice; these patients had dentofacial deformities and underwent Lefort I osteotomy procedures. For the full patient group, 888 patients (72%) were women; in the turbinectomy group, 403 (67%) were women. The anteroposterior, transverse, and vertical dimensions of the mandible, maxilla, and occlusal plane of each subject were assessed, in addition to cephalometric analysis and determination of the presence or absence of temporomandibular joint disorders. PIT, when indicated, was performed after downfracture of the maxilla, providing access to the turbinates where approximately two thirds of the total turbinate volume was removed and septoplasty was completed if indicated. Hypertrophied turbinates causing significant nasal airway obstruction were present in 603 (49%) of the 1234 patients undergoing Le Fort I osteotomy. The results of this study showed that PIT performed simultaneously with Le Fort I osteotomy is a safe method of managing nasal airway obstruction related to hypertrophied turbinates with minimal complications.

Dentition, bone loss, and the aging of the mandible

BACKGROUND

Facial aging is a dynamic process with impact on both the soft tissues and the bones. Despite a growing body of evidence, controversy still exists regarding absolute characteristics of the aging facial skeleton.

OBJECTIVE

The purpose of this study was to investigate various mandibular measurements in different age groups and to delineate the relation of the dentition to these parameters.

METHODS

Ninety Caucasian mandibles were assessed for the following distance landmarks: gonion-gonion, infradentale-gnathion, mental foramen-mandibular crest, mental foramen-inferior mandibular border, gnathion-gonion, condyle-gonion, and gonial angle. The measurements were compared according to age, sex, and dentition.

RESULTS

The number of teeth decreased significantly with increasing age in males (P = .002) and females (P < .001). There were no other statistically significant differences between age groups for the rest of the parameters. The infradentale-gnathion distance (P = .005) and the mental foramen-mandibular crest distance (P < .001) was found to increase with total number of teeth. Other parameters did not show a significant relation to dentition. All parameters were significantly larger in the male subgroups with the exception of gnathion-gonion distance and gonial angle. Bilateral mandibular measurements were symmetric except for the gonial angle, which was more obtuse on the right side in males (P = .007) and females (P = .018).

CONCLUSIONS

Our findings support previous evidence that dentition is the main determinant of the morphology of the mandible. The skeletal characteristics are variable among individuals, and a longitudinal study is required to better understand age-related changes of the mandible.

Natural head position and growth of the facial part of the skull

The aim of this study was to determine any correlation between natural head position and cranio-cervical growth direction and if natural head position influences facial growth direction. One hundred sixty (160) cephalometric radiographs were examined and cranio-cervical inclinations determined (angles: NS-Ver, NS-OPT, NS-CVT). On the basis of the NS-ML angle, radiographs were divided into two groups: mandibular anteriorotation and posteriorotation. On the basis of the SGo/NMe index, two groups were formed: short-faced and long-faced subjects. The angles NS-Ver, NS-OPT, and NS-CVT describe cranio-cervical inclination. Subjects with anterior mandible growth do position their heads more vertically and have a shorter face, and those with posterior mandible growth tilt their heads more backwards and have a longer face. An adaptive head position can be a factor in altering the direction of facial growth. Determination of head position and mandible growth direction can be an important indicator in patients with TMD treatment.

A long-term evaluation of 150 costochondral nasal grafts

INTRODUCTION

This paper reviewed the outcome of cantilevered costochondral grafts used for dorsal nasal augmentation in the management of patients treated at the Australian Craniofacial Unit (ACFU), Adelaide over a 29-year period.

MATERIALS AND METHODS

All patients undergoing dorsal nasal augmentation with costochondral grafts as part of their craniofacial management between 1981 and 2009 were identified using the ACFU database, and their medical notes were reviewed.

RESULTS

107 patients (50 M, 57 F), with a mean age of 12.3 years (range: 2-62 years) and requiring a total of 150 costochondral grafts, were identified from the departmental database. Mean follow-up after nasal augmentation was 5.6 years (1 month-31.5 years). 46% of the patients were diagnosed with Binder syndrome/Chondrodysplasia punctata; other diagnoses included Tessier midline clefts, cleft lip and palate and frontonasal dysplasia. A dorsal midline incision (49%) was the commonest method of access, with 84% of patients having mini-screw fixation for graft stabilisation. Complications included screw palpability, infection, skin necrosis and graft fracture. The commonest reasons for a replacement graft were graft atrophy and fracture, infection and persistent deformity.

CONCLUSION

Cantilevered nasal costochondral grafting is an excellent technique for improving nasal contour and function in a wide variety of clinical situations.

Postnatal changes in the growth dynamics of the human face revealed from bone modelling patterns

Human skull morphology results from complex processes that involve the coordinated growth and interaction of its skeletal components to keep a functional and structural balance. Previous histological works have studied the growth of different craniofacial regions and their relationship to functional spaces in humans up to 14 years old. Nevertheless, how the growth dynamics of the facial skeleton and the mandible are related and how this relationship changes through the late ontogeny remain poorly understood. To approach these two questions, we have compared the bone modelling activities of the craniofacial skeleton from a sample of subadult and adult humans. In this study, we have established for the first time the bone modelling pattern of the face and the mandible from adult humans. Our analyses reveal a patchy distribution of the bone modelling fields (overemphasized by the presence of surface islands with no histological information) reflecting the complex growth dynamics associated to the individual morphology. Subadult and adult specimens show important differences in the bone modelling patterns of the anterior region of the facial skeleton and the posterior region of the mandible. These differences indicate developmental changes in the growth directions of the whole craniofacial complex, from a predominantly downward growth in subadults that turns to a forward growth observed in the adult craniofacial skeleton. We hypothesize that these ontogenetic changes would respond to the physiological and physical requirements to enlarge the oral and nasal cavities once maturation of the brain and the closure of the cranial sutures have taken place during craniofacial development.

Facial morphogenesis of the earliest europeans

The modern human face differs from that of our early ancestors in that the facial profile is relatively retracted (orthognathic). This change in facial profile is associated with a characteristic spatial distribution of bone deposition and resorption: growth remodeling. For humans, surface resorption commonly dominates on anteriorly-facing areas of the subnasal region of the maxilla and mandible during development. We mapped the distribution of facial growth remodeling activities on the 900-800 ky maxilla ATD6-69 assigned to H. antecessor, and on the 1.5 My cranium KNM-WT 15000, part of an associated skeleton assigned to African H. erectus. We show that, as in H. sapiens, H. antecessor shows bone resorption over most of the subnasal region. This pattern contrasts with that seen in KNM-WT 15000 where evidence of bone deposition, not resorption, was identified. KNM-WT 15000 is similar to Australopithecus and the extant African apes in this localized area of bone deposition. These new data point to diversity of patterns of facial growth in fossil Homo. The similarities in facial growth in H. antecessor and H. sapiens suggest that one key developmental change responsible for the characteristic facial morphology of modern humans can be traced back at least to H. antecessor.