Craniofacial malformations and the orthodontist

Computed tomography assessment of hypodontia and crown size in hemifacial microsomia

OBJECTIVE

Our aims were to assess the prevalence of hypodontia in unilateral hemifacial microsomia (HFM), and to compare tooth (crown) size between affected and unaffected sides.

DESIGN

In a retrospective cross-sectional study of South Australians, computed tomography (CT) scans were used to assess hypodontia and crown size (mesiodistal length, buccolingual width and crown height). The inclusion criteria were the absence of other congenital anomalies and the availability of CT scans. The exclusion criteria were the lack of extraction history or reproducible landmarks for morphometric assessment. The final sample comprised 41 participants in both dentitions, including 32 children and 9 adults (median age 13.9 years, range 0.4 - 47.6 years; 19 males and 22 females). Hypodontia was assessed in all participants, and the permanent crown size in 30 (73.2%) participants. Linear mixed-effects models were performed to determine if crown size was significantly different between the two sides, controlling for sex, HFM severity, and tooth and jaw type.

RESULTS

Hypodontia occurred in none of the participants in the primary dentition, but in 6/30 (20%) participants in the permanent dentition (3/30 each on the affected and unaffected sides). There was no significant difference in the mean crown dimensions between the two sides, but the crown size was larger in males (p < 0.05), except for mesiodistal length, and became progressively smaller with increased HFM severity (p < 0.05).

CONCLUSIONS

Hypodontia spared the primary dentition but featured prominently in the permanent dentition. The permanent crown dimensions were unaltered between the two sides.

Gene-environment interactions in the pathogenesis of common craniofacial anomalies

Craniofacial anomalies often exhibit phenotype variability and non-mendelian inheritance due to their multifactorial origin, involving both genetic and environmental factors. A combination of epidemiologic studies, genome-wide association, and analysis of animal models have provided insight into the effects of gene-environment interactions on craniofacial and brain development and the pathogenesis of congenital disorders. In this chapter, we briefly summarize the etiology and pathogenesis of common craniofacial anomalies, focusing on orofacial clefts, hemifacial microsomia, and microcephaly. We then discuss how environmental risk factors interact with genes to modulate the incidence and phenotype severity of craniofacial anomalies. Identifying environmental risk factors and dissecting their interaction with different genes and modifiers is central to improved strategies for preventing craniofacial anomalies.

Apert syndrome: an informative long-term dentofacial outcome

The management of patients with Apert syndrome (AS) is complex and reflects the multisystem disease as a result of premature fusion of cranial vault, cranial base and midface sutures as well as extremity anomalies characterised by syndactyly. Early cranial sutural fusion results in craniocerebral disproportion which can lead to crisis surgical intervention due to raised intracranial pressure, ophthalmic and compromised airway concerns. Childhood inventions are often determined by psychosocial concerns and adult surgical interventions are often determined by cosmetic concerns. Treatments are provided by many different specialists within multidisciplinary teams (MDT). The treatment pathway extends from birth well into adulthood and is often associated with a heavy burden of care. Due to the extensive nature of the interaction with these patients MDT members have opportunities to provide enhanced patient-centred care and support.This case report provides an overview of the current knowledge of the aetiology of AS, illustrates the pathway of surgical and non-surgical management of AS and provides a long-term review of the dentofacial treatment outcomes.By having a better understanding of the impact of AS and treatment provided, MDT members can not only provide improved clinical treatment but also offer improved patient experiences for those with craniofacial anomalies, in particular, an increased awareness of the psychosocial challenges they endure.

Using orthodontic elastic traction during the active period of distraction osteogenesis to increase the effective vertical extension of hemifacial microsomia patients: A multi-center randomized clinical trial

In this study, the aim was to assess whether using elastic traction during the active period of distraction osteogenesis could effectively increase the vertical extension. Patients with Pruzansky-Kaban Type II mandibular deformity were recruited and randomly assigned into Elastic traction + Distraction Osteogenesis group or Distraction Osteogenesis group, respectively. During the active period, the experimental group received orthodontic elastic traction 3 days after distraction osteogenesis implantation, while the control group received no treatment. All the participants underwent computed tomography (CT) examination before surgery, at the end of the active period, 6 months and 2 years after distraction osteogenesis tractor implantation. The primary outcome was the effective vertical extension rate of the mandible from the baseline to the end of the active period after operations, and there were 7 secondary outcomes used. 70 patients were included. The effective vertical extension rates were 85.021% ± 7.432% (mean ± SD) and 68.811% ± 9.510% (mean ± SD) in the experimental and control groups, respectively (P = 0.001). The average distances between the lower middle incisor point to the sagittal plane at the end of the active period were 2.485 ± 1.411 mm and 3.938 ± 2.293 mm in the experimental and control groups, respectively (P = 0.026). At the end of the active period of distraction osteogenesis, the average values of the mandibular occlusal plane canting were -4.887 ± 3.126 mm and -0.177 ± 4.029 mm in the experimental and control groups, respectively (P = 0.026). Elastic traction-assisted distraction osteogenesis could improve traction efficiency and facial symmetry.

Long-term treatment outcomes from a patient's perspective with Treacher Collins syndrome

The management of patients with Treacher Collins Syndrome (TCS) is complex and involves many different specialists within multidisciplinary teams (MDT). The treatment pathway extends from birth well into adulthood and is associated with a heavy burden of care. Due to the extensive nature of the interaction with these patients, MDT members have opportunities to provide enhanced patient-centred care and support.This case report provides an overview of the current knowledge of the aetiology of TCS, the management of these patients and provides a unique perspective from one of the coauthors who has TCS and reports on his treatment experiences and long-term treatment outcomes. By having a better understanding of the impact of TCS and treatment provided, MDT members can not only provide improved clinical treatment but also offer improved patient experiences for those with craniofacial anomalies in particular an increased awareness of the psychosocial challenges they endure.

Goldenhar Syndrome With Ankylosis of the Temporomandibular Joint: A Case Report

Goldenhar syndrome, or oculoauriculovertebral dysplasia, represents approximately 10% of craniofacial microsomia anomalies. These patients have a variety of clinical features that are relevant to anesthesia providers, including a high-arched palate, mandibular hypoplasia, micrognathia, and temporomandibular joint (TMJ) malformation. The oral manifestations of Goldenhar syndrome range from malocclusion to complex TMJ involvement. Outside of the dental and oral surgery literature, the potential for TMJ ankylosis in Goldenhar patients is seldom emphasized. TMJ ankylosis impacts airway management, and anesthesia providers must be aware of this clinical phenotype when planning the anesthetic care of patients with Goldenhar syndrome.

Investigating perceptions of patient-centred care in orthodontics

Objectives:

To assess and compare patient and clinician perceptions of patient-centredness for adults about to commence active orthodontic treatment, and to assess whether the following variables affected perceptions of patient-centredness: patient gender and age; clinician gender and grade; and stage of treatment.

Design:

A prospective, cross-sectional questionnaire study.

Setting:

Eastman Dental Hospital, UCLH NHS Foundation Trust.

Participants:

A total of 112 adult patients and 30 clinicians completed 224 questionnaires (112 patient and 112 clinician questionnaires).

Methods:

A validated, dyadic questionnaire, the ‘9-Item Patient Perception of Patient-Centredness’ (PPPC), was used to collect data from both patients and their corresponding clinicians after initial assessment or records/treatment planning consultations. Total PPPC scores (possible score range = 9–36) were calculated for each patient and clinician to ascertain the extent to which they perceived they were engaging in patient-centredness, where higher scores corresponded with better performance.

Results:

Patients and clinicians perceived high engagement in patient-centredness with median scores of 32/36 and 29/36, respectively. There was a statistically significant difference between total scores with patients perceiving consultations to be more patient-centred than clinicians ( P < 0.001). None of the variables (patient gender and age, clinician gender and grade, stage of treatment) were statistically significant.

Conclusion:

Patients and clinicians both perceived high engagement in patient-centredness. Patients perceived consultations to be significantly more patient-centred than clinicians ( P < 0.001).

Modeling Medical Education: The Impact of Three-Dimensional Printed Models on Medical Student Education in Plastic Surgery

PURPOSE

Trainee exposure to craniofacial pathology can be limited due to rare disease presentation, revealing a need for tools that assist in visualizing complex 3D pathologic anatomy. 3D-printed models show potential as a useful aid, allowing for physical manipulation and hands-on experience. This study investigates their educational value in teaching craniofacial pathology and surgical repair.

METHODS

Forty-four medical students randomly assigned to a control group or model group were given a PowerPoint presentation-based module on craniosynostosis and surgical repair. The model group was also provided with 3D-printed models of sagittal, metopic, and bicoronal synostosis, created using patient-specific preoperative computed tomography data. A survey using the Likert scale evaluated participants' learning experience. Pre- and postmodule scores on a 10-question multiple choice quiz were recorded.

RESULTS

The survey showed that students in the model group reported better understanding of the anatomy (4.86 ± 0.15 versus 4.26 ± 0.22; P = 0.0001) and visualization of the pathology (4.76 ± 0.23 versus 4.26 ± 0.25; P = 0.0064), gaining an improved understanding of surgical approach (4.38 ± 0.37 versus 3.83 ± 0.29; P = 0.0266), which was more effectively taught (4.24 ± 0.33 versus 3.30 ± 0.38; P = 0.0007) with the 3D-printed models. The mean pre- and post-module quiz scores between groups were similar.

CONCLUSION

3D-printed models demonstrated an improved learning experience for medical students as shown by survey. These findings suggest a potential use for 3D-printed models in medical education of craniofacial pathology and surgery.

Craniofacial, orofacial and dental disorders: the role of the RAS/ERK pathway

Deviations from the precisely coordinated programme of human head development can lead to craniofacial and orofacial malformations often including a variety of dental abnormalities too. Although the aetiology is still unknown in many cases, during the last decades different intracellular signalling pathways have been genetically linked to specific disorders. Among these pathways, the RAS/extracellular signal-regulated kinase (ERK) signalling cascade is the focus of this review since it encompasses a large group of genes that when mutated cause some of the most common and severe developmental anomalies in humans. We present the components of the RAS/ERK pathway implicated in craniofacial and orodental disorders through a series of human and animal studies. We attempt to unravel the specific molecular targets downstream of ERK that act on particular cell types and regulate key steps in the associated developmental processes. Finally we point to ambiguities in our current knowledge that need to be clarified before RAS/ERK-targeting therapeutic approaches can be implemented.

Crouzon Syndrome: a Comprehensive Review

Crouzon syndrome is a rare genetic disorder with autosomal dominant inheritance. The underlying pathological process is premature synostosis of the cranial sutures with subsequent phenotypic alterations of the affected person. A review of the literature has been conducted in order to resume the overall characteristics of Crouzon syndrome such as craniomaxillofacial malformations, clinical features, dentoalveolar characteristics, aesthetic impairments, and psychological background, as well as, the different therapeutic procedures, which combine surgical and orthodontic interventions. Facial and functional malformations in individuals with Crouzon syndrome could be significantly improved after a series of surgical and orthodontic procedures in almost all cases. A multidisciplinary treatment approach would provide the best outcomes in affected patients.

A Survey of Orthodontic Treatment in Team Care for Patients With Syndromic Craniosynostosis in Japan

OBJECTIVE

To understand the actual condition of orthodontic treatment in team care for patients with syndromic craniosynostosis (SCS) in Japan.

DESIGN

A nationwide collaborative survey.

SETTING

Twenty-four orthodontic clinics in Japan.

PATIENTS

A total of 246 patients with SCS.

MAIN OUTCOME MEASURE

Treatment history was examined based on orthodontic records using common survey sheets.

RESULTS

Most patients first visited the orthodontic clinic in the deciduous or mixed dentition phase. Midface advancement was performed without visiting the orthodontic clinic in about a quarter of the patients, and more than a half of the patients underwent "surgery-first" midface advancement. First-phase orthodontic treatment was carried out in about a half of the patients, and maxillary expansion and protraction were performed. Tooth extraction was required in about two-thirds of patients, and the extraction of maxillary teeth was required in most patients. Tooth abnormalities were found in 37.8% of patients, and abnormalities of maxillary molars were frequently (58.3%) found in patients who had undergone midface surgery below the age of 6 years.

CONCLUSIONS

Many patients underwent "surgery-first" midface advancement, and visiting the orthodontic clinic at least before advancement was considered desirable. First-phase orthodontic treatment should be performed considering the burden of care. Midface advancement below the age of 6 years had a high risk of injury to the maxillary molars. This survey is considered useful for improving orthodontic treatment in team care of patients with SCS.

Update on 13 Syndromes Affecting Craniofacial and Dental Structures

Care of individuals with syndromes affecting craniofacial and dental structures are mostly treated by an interdisciplinary team from early childhood on. In addition to medical and dental specialists that have a vivid interest in these syndromes and for whom these syndromes are of evident interest, experts of scientific background-like molecular and developmental geneticists, but also computational biologists and bioinformaticians-, become more frequently involved in the refined diagnostic and etiological processes of these patients. Early diagnosis is often crucial for the effective treatment of functional and developmental aspects. However, not all syndromes can be clinically identified early, especially in cases of absence of known family history. Moreover, the treatment of these patients is often complicated because of insufficient medical knowledge, and because of the dental and craniofacial developmental variations. The role of the team is crucial for the prevention, proper function, and craniofacial development which is often combined with orthognathic surgery. Although the existing literature does not provide considerable insight into this topic, this descriptive review aims to provide tools for the interdisciplinary team by giving an update on the genetics and general features, and the oral and craniofacial manifestations for early diagnosis. Clinical phenotyping together with genetic data and pathway information will ultimately pave the way for preventive strategies and therapeutic options in the future. This will improve the prognosis for better functional and aesthetic outcome for these patients and lead to a better quality of life, not only for the patients themselves but also for their families. The aim of this review is to promote interdisciplinary interaction and mutual understanding among all specialists involved in the diagnosis and therapeutic guidance of patients with these syndromal conditions in order to provide optimal personalized care in an integrated approach.

The Relationship between Brachycephalic Head Features in Modern Persian Cats and Dysmorphologies of the Skull and Internal Hydrocephalus

Background

Cat breeders observed a frequent occurrence of internal hydrocephalus in Persian cats with extreme brachycephalic head morphology.

Objective

To investigate a possible relationship among the grade of brachycephaly, ventricular dilatation, and skull dysmorphologies in Persian cats.

Animals

92 Persian‐, 10 Domestic shorthair cats.

Methods

The grade of brachycephaly was determined on skull models based on CT datasets. Cranial measurements were examined with regard to a possible correlation with relative ventricular volume, and cranial capacity. Persians with high (peke‐face Persians) and lower grades of brachycephaly (doll‐face Persians) were investigated for the presence of skull dysmorphologies.

Results

The mean cranial index of the peke‐face Persians (0.97 ± 0.14) was significantly higher than the mean cranial index of doll‐face Persians (0.66 ± 0.04; P < 0.001). Peke‐face Persians had a lower relative nasal bone length (0.15 ± 0.04) compared to doll‐face (0.29 ± 0.08; P < 0.001). The endocranial volume was significantly lower in doll‐face than peke‐face Persians (89.6 ± 1.27% versus 91.76 ± 2.07%; P < 0.001). The cranial index was significantly correlated with this variable (Spearman's r: 0.7; P < 0.0001). Mean ventricle: Brain ratio of the peke‐face group (0.159 ± 0.14) was significantly higher compared to doll‐face Persians (0.015 ± 0.01; P < 0.001).

Conclusion and Clinical Relevance

High grades of brachycephaly are also associated with malformations of the calvarial and facial bones as well as dental malformations. As these dysmorphologies can affect animal welfare, the selection for extreme forms of brachycephaly in Persian cats should be reconsidered.