The Royal Children's Hospital Melbourne

Research

Current Research

Currently the MRUFD has two primary research themes relating to teeth and bone. Being complementary at both the biological and medical levels, these companion topics hold broad relevance across the oral, dental and craniofacial fields. As such, this dual-theme effort provides a strong foundation for future expansion into a variety of clinical areas.

1. Cause and prevention of Developmental Dental Defects

Capitalising on Prof. Hubbard's experience in the biology of enamel-forming cells and calcium regulation, a major research thrust of the MRUFD is to improve understanding of Developmental Dental Defects (DDD). We hope to not only help improve treatment options but ultimately to achieve prevention of DDD in many cases, through understanding their causes. DDD have a disturbingly high prevalence, affecting 5 — 20% of adolescents worldwide. Consequently DDD bring high costs to patients and society, particularly through increased risk of dental decay and pain. The most common types of DDD are acquired during infancy, apparently as a result of injury to the tooth-forming cells. It remains unclear what causes such cellular injuries, although suspicions centre on environmental toxins and several factors associated with childhood illness. A multi-talented research team comprising clinicians (Drs Garry Nervo, Roger Hall, Edmond Lobaza, Nicky Kilpatrick, David Manton, Felicity Crombie), and scientists (Hubbard Laboratory, Dr Joseph Palamara, A/Prof. Andrew Peele) has been assembled to tackle these questions. Having secured competitive funding (NHMRC, Dentsply), the team is applying a variety of biochemical, biophysical and structural approaches to human specimens and experimental models of DDD.

2. Surgical and biological manipulation of bone production and morphology

The MRUFD maintains a strong interest in the biological behaviour of bone at several levels, ranging from the remodelling of facial bones following repositioning to the generation of new bone using distraction techniques in craniofacial syndromes. Major skeletal defects often require more bone for replacement than is available from the patient. The ability to grow (‘culture’) bone outside the body or at the site of the defect for repair of craniomaxillofacial defects is an aspiration for scientists worldwide. The new field of tissue regeneration challenges the hugely successful era of hard and soft tissue reconstruction based on flaps and free vascularised transfer. Enormous interest surrounds the use of stem cell technology to replace damaged tissues, ranging from bone and cartilage to cardiac muscle.

Although repositioning components of the facial skeleton by performing osteotomies has been well established for several decades, uncertainties remained about the response and stability to certain movements of the jaws in three dimensions using contemporary fixation. This question continues to be investigated by Assoc. Prof. Heggie's team in the Department of Plastic and Maxillofacial Surgery.

Techniques to lengthen bones of the facial skeleton (distraction osteogenesis) were pioneered in the early 1990s and initially involved mandibular lengthening in patients with diminutive jaws (micrognathia). This application broadened to include advancement of the mid-face in cases of cleft lip and palate and the syndromic craniosynostoses. Many internal and external devices have been trialled for regular clinical use and protocols have been developed for the use of these techniques, leading to publications on this topic.

See story in The Age

Upper airway obstruction is an increasingly recognised condition in paediatric patients with craniofacial anomalies. The application of mini-internal devices to lengthen the mandible in neonates and infants with Robin Sequence and other micrognathic conditions was commenced early this century in conjunction with the Departments of Neonatology and Respiratory Medicine and we were one of the first groups in the world to conduct a prospective series for investigation. Similarly internal and external devices have been applied to young patients with obstructed airways due to hypoplastic mid-facial structures. Distraction osteogenesis in these groups has revolutionized their management by avoiding tracheostomies, by removing the need for noctural supplemental oxygen and has led to earlier discharge from hospital and the more rapid establishment of feeding. Studies are continuing in these areas and publications are being prepared.

Cranial defects resulting from various conditions have proved to be a challenge to the surgeon as the availability of sufficient bone to use for repair is not always possible. With the development of bone substitutes, stem cell research and agents that promote bone healing, investigation of ways to effectively avoid the use of patient donor sites has been undertaken by the Unit. The successful use of fresh frozen irradiated allografted bone using the rabbit critical size cranial defect was published, and a similar outcome involving a resorbable polymer was achieved by Dr. Peter Farlie and his team. Currently, the use of a decellularized connective tissue matrix is being investigated in the same model.

3. Molecular foundations of facial development and abnormality

On arrival of Prof. Hubbard in 2003, the MRUFD worked with Dr Peter Farlie (Murdoch Childrens Research Institute and Deputy Director, Research, Department of Plastic and Maxillofacial Surgery) to initiate a ground-breaking programme investigating the molecular foundation of facial development. This research is important because it provides a new method of investigating the pathogenesis of abnormalities in facial development that lead to birth defects such as clefting disorders, cranial shape abnormalities (craniosynostoses) and absent teeth. By combining Dr. Farlie's experience in craniofacial embryology with Prof. Hubbard's skills in 'proteomics' (a cutting-edge technology involving the analysis of many proteins simultaneously), a new way of learning about the cells that form the lower face (including jaw and teeth) became possible. With seed funding from the MRUFD, this study progressed well and the early findings were published in a widely read multidisciplinary journal, 'Proteomics'. Dr Firas Alsoleihat (a dental graduate from Jordan) joined this project in 2005, and his extension of the proteomics studies and development of other new research avenues led to successful completion of a PhD in 2008.

4. Other research interests

A variety of other research avenues of interest to the MRUFD will be pursued as appropriate funding and resources become available, including:

• Using the new discipline of 'phenomics' (a type of reverse genetics) to investigate the genetic foundation of common craniofacial disorders
• Using proteomics and metabolomics to help develop novel biomarkers of use in the dental and bone fields
• Interpretation and management of cleft palate speech disorders
• Identification of cellular populations in neural crest tissue
• Molecular genetics of facial anomalies
  

Research Grants

The MRUFD has a Research Advisory Committee to assess potential projects for seed funding. For study proposals that require additional specialized knowledge, appraisal is sought both locally and further afield as appropriate.

The grants disbursed to date are summarized here. Several research papers have been publishedﾠand other studies are still in progress. Financial support from MRUFD has assisted the successful completion of three PhD programs (Dr Julie Reid, Royal Children's Hospital; Dr Roy Judge, School of Dental Science; and Dr Firas Alsoleihat, Murdoch Childrens Research Institute).

Interested parties (medical and dental practitioners and scientists) should contact the Director about the current availability of funding, and pursue the application process using this Research Grant Application Form (MS Word Document, 32.5Kb).

Research Grants awarded by the MRUFD

1. An investigation into Masticatory Bone Strain Using In Vitro and In Vivo Canine Models. (Judge et al.)  $12,000
2. Elucidation of the genetic basis of Amelogenesis Imperfecta (Aldred et al.)  $17,260
3. Feeding difficulties in infants with cleft lip and /or palate: an overrated problem or a neglected aspect of care? (Reid et al.)  $12,500
4. The use of Electro-palatography (EPG) in the assessment and management of speech deficits in children with cleft lip and palate (Reilly et al)  $7,000
5. The fate of dermis grafts in the sheep TMJ following discectomy (Brown & Ferguson)  $10,165
6. Human Masseter Muscle Structure and Function in Subjects with Different Underlying Vertical Facial Patterns (Woods et al)  $40,272
7. Osseointegration in children and young adults with Ectodermal Dysplasia and Cleft Lip and Palate. A two part study involving clinical evaluation and psychological assessment. (Sweeney et al)  $11,365
8. The significance of tongue-tie: a study of Australian surgeons (Ms. Sally Brinkmann et al.)  $800
9. Difficult intubation induced by maxillary distraction device placement in craniosynostosis syndromes. (Roche et al., Dept. Anaesthesia)  $200
10. A retrospective study of alveolar bone grafts in cleft patients at the Royal Children's Hospital, Melbourne, 1996-1999. (Hogan)  $500
11. Craniofacial microsomia: experience using the OMENS-Plus classification at the Royal Children's Hospital of Melbourne. (Poon)  $500
12. Molecular phenotyping in cranial neural crest cells - a pilot application of microsample proteomics analysis. (Farlie, Hubbard)  $10,000
13. Proteomic profiling of facial development (Farlie, Hubbard)  $10,000
14. Proteomic characterisation of enamel affected by idiopathic molar hypomineralization (Crombie, Mangum) $5,000

Research publications supported by the MRUFD

1. Unusual jaw lesions in the paediatric and adolescent patient: a management challenge. Heggie AA. Ann R Aust Coll Dent Surg. (2000) 15:185-192 (PMID: 11709936)
2. Difficult tracheal intubation induced by maxillary distraction devices in craniosynostosis syndromes. J Roche, G Frawley, A Heggie. Paediatr Anaesth. (2002) 12:227-234 (PMID: 11903936)
3. LeFort III internal distraction in syndromic craniosynostosis. Holmes AD, Wright GM, Meara J, Heggie AA, Probert T. J Craniofac Surg (2002) 13:262-272 (PMID: 12000884)
4. Allogeneic bone grafting of calvarial defects: an experimental study in the rabbit. Shand JM, Heggie AA, Holmes AD, Holmes W. Int. J. Oral Maxillofac Surg (2002) 31:525-531 (PMID: 12418569)
5. A comparison of the stability of single-piece and segmental Le Fort I maxillary advancements. Arpornmaeklong P, Heggie AA, Shand J M. J Craniofac Surg (2003) 14:3-9 (PMID: 12544214)
6. Hemifacial Microsomia: use of the OMENS-Plus classification at the Royal Children's Hospital of Melbourne. Poon C-H, Meara JG, Heggie AA. Plast Reconstr Surg (2003) 111:1011-8 (PMID: 12621170)
7. Canine eruption into grafted alveolar clefts: A retrospective study. Hogan L, Shand JM, Heggie AA, Kilpatrick K Aust. Dental J (2003) 48:119-124 (PMID: 14649402)
8. Juvenile mandibular chronic osteomyelitis: a distinct clinical entity. Heggie AA, Shand JM, Aldred MJ, Talacko AA Int. J Oral Maxillofac Surg (2003) 32:459-468 (PMID: 14759102)
9. Stability of combined Le Fort I maxillary advancement and mandibular reduction. Arpornmaeklong P, Shand JM, Heggie AA. Aust Ortho J. (2003) 19:57-66 (PMID: 14703330)
10. Internal mandibular distraction to relieve airway obstruction in infants and young children with micrognathia. Chigurupati R, Massie J, Dargaville P, Heggie AA. Pediatr Pulmonol. (2004) 37:230-235 (PMID: 14966816)
11. Skeletal stability following maxillary impaction and mandibular advancement. Arpornmaeklong P, Shand JM, Heggie AA. Int. J. Oral Maxillofac Surg. (2004) 33:656-663   (PMID: 15337178)
12. Feeding interventions for growth and development in infants with cleft lip, cleft palate or cleft lip and palate. Glenny AM, Hooper L, Shaw WC, Reilly S, Kasem S, Reid JA. In: Cochrane Database Syst Rev. (2004) 3:CD003315 (PMID: 15266479) 
13. Accessing the evidence to treat the dysphagic patient: can we get it? Is there time? Brener L, Vallino-Napoli LD, Reid JA, Reilly S. Asia Pacific Journal of Speech, Language & Hearing (2003) 8:36-43
14. A review of feeding interventions for infants with cleft palate. Reid JA. Cleft Palate-Craniofacial Journal (2004) 41:268-278 (PMID: 15151444) 
15. ERp29, a general endoplasmic reticulum marker, is highly expressed throughout the brain. Macleod JC, Sayer RJ, Lucocq JM and Hubbard MJ.ﾠJ. Comp. Neurol. (2004) 477:29-42 (PMID: 15281078) 
16. Purification and biochemical characterisation of native ERp29 from rat liver. Hubbard MJ, Mangum JE and McHugh NJ. Biochem. J. (2004) 383:589-598 (PMID: 15500441)
17. Calbindin-independence of calcium transport in developing teeth contradicts the calcium-ferry dogma. Turnbull CI, Looi K, Mangum JE, Meyer M, Sayer RJ and Hubbard MJ. J. Biol. Chem. (2004) 279:55850-55854 (PMID: 15494408) 
18. The role of distraction osteogenesis in the management of craniofacial syndromes. Shand JM, Smith KS, Heggie AA. Oral and Maxillofacial Clinics of North America. (2004) 16:525-504. (PMID: 18088752)
19. Biophysical characterization of ERp29: evidence for a key structural role of Cysteine-125. Hermann VM, Cutfield JF and Hubbard MJ. J. Biol. Chem. (2005) 280:13529-13537 (PMID: 15572350)
20. Proteomic profiling of facial development in chick embryos. Mangum JE, Farlie PG and Hubbard MJ. Proteomics (2005) 5:2542-50(PMID: 15912509)
21. Internal mandibular distraction to relieve airway obstruction in infants and young children with micrognathia. Chigurupati R, Massie J, Dargaville P, Heggie AA. Pediatr Pulmonol. (2004) 37:230-235. (PMID: 14966816) 
22. Treatment outcomes for adolescent ectodermal dysplasia patients treated with dental implants. Sweeney IP, Ferguson JW, Heggie AA, Lucas JO. Int J Paediatr Dent. (2005) 15:241-248.   (PMID: 16011782) 
23. Osseointegrated implant anchorage in a growing adolescent. Schneider PM, Heggie AA, Roberts WE. Semin Orthod. (2006) 12:272-283.
24. Cysts of the jaws and advances in the diagnosis and management of naevoid basal cell carcinoma syndrome. Shand JM, Heggie AA Oral Maxillofac. Surg. Clin. North Am. 2005;17:403-414. (PMID: 18088795) 
25. Towards second-generation proteome analysis of murine enamel-forming cells. Mangum JE, Veith PD, Reynolds EC, Hubbard MJ Eur. J. Oral Sci. 114 (2006) (S1):259-265 (PMID: 16674695) 
26. Triplex profiling of functionally distinct chaperones (ERp29/PDI/BiP) reveals marked heterogeneity of the endoplasmic reticulum in cancer. Shnyder SD, Mangum JE, Hubbard MJ J. Proteome Res. (2008) 7, 3364-3372 (PMID: 18598068) 
27. Complete correction of severe scaphocephaly: The Melbourne method of total remodeling. Greensmith AL, Holmes AD, Lo P, Maxiner W, Heggie AA, Meara JG Plast. Reconstr. Surg. 2008;121:1300-1310. (PMID: 18349649)
28. Prenatal and postnatal management of congenital granular cell tumours: A case report. Williams RW, Grave B, Stewart M, Heggie AA. Br. J. Oral Maxillofac. Surg. 2008 Jun 13 (PMID: 18556098)