Submitted by: Theodore Belfor
Introduction
Palatal expansion in adult patients is a relatively new concept. Ever since Grays Anatomy the bible for dental students studying anatomy, we all believed that the cranial sutures fuse solid when we become non-growing adults. In an interview for Dental Press Magazine of Orthodontic and Facial Orthopedics in 2002, Donald H Enlow, author of three books on Cranium Facial Growth and 170 scientific articles, Dr Enlow, when queried Is there any craniofacial growth after 20 years of age? Answered,yes. Futhermore, he states, A capacity for facial remodeling in adults is retained throughout life. He also states,We must utilize three-dimensional evaluation based on an individuals actual growth and development. The Homeoblock functional appliance produces noticeable facial changes in adult patients in four to six months. We have viewed these changes in three-dimensions using stereophotogrammetry. In an article published Quantification of facial morphology using stereophotogrammetry–demonstration of a new concept. It is concluded that stereophotogrammetry is a suitable 3-D registration method for quantifying and detecting developmental changes in facial morphology. (1)
Abstract
Maxillary arch changes using the Homeoblock appliance have been reported and published in the Functional Orthodontist (2). The purpose of this paper is to look more closely at the facial changes that occur when we remodel the maxillary dental arch wider in the course of palatal expansion. To observe and understand these changes a review of the anatomy of the region is included.
Zygomatic bone (green)
Maxilla (orange)
Malar bone (in contact with the temporal frontal sphenoid and maxilla) (beige)
Four muscles from left to right
Zygomaticus majo
Zygomaticus mino
Levato Labii Superiorus
Obicularis Oris
Looking at the anatomy of the area we can see how the remodeling of the maxilla can easily affect the malar and the zygomatic bones. Since the muscle attachments are on the bone we can see how the muscles which insert into the muscle and soft tissue around the mouth can also affect the fullness of the lips. Optimal development of the lateral aspects of the face especially the malar and zygomatic bones make it easier for the patient to smile. The paper will examine three dimensional images of patients, pre and post treatment with the Homeoblock appliance. We choose the profile view to illustrate the changes most clearly. It is concluded that the Homeoblock appliance creates observable changes around the eyes, in the area of the cheekbone and around the mouth.
Case Reports
Patient A
The first patient is a sixty year old female that presented to the office for teeth straightening, and porcelain laminate veneers. A three-dimensional Stereophotogrammetry image was taken using a 3dMD facial capture system.
The pre and post photos clearly show changes around the eyes, at the area of the cheekbones and around the mouth consistent with remodeling the underlying maxillary and zygomatic bone structures wider.
[youtube]http://www.youtube.com/watch?v=gThYbmxQgnE[/youtube]
Patient B
The second patient a fifty year old female was treated six months with a Homeoblock appliance to reduce age lines in the face. Stereophotogrammetry images were taken pre and post treatment. The photos were then evaluated using the 3dMD facial capture software to evaluate the changes that occurred.
Pre and post profile
3dMD software was used to evaluate facial changes. An increase in facial width of almost 4 millimeters was observed.
Pre and post full face photos
Pre and post intra oral photos showing the Homeoblock appliance in place.
Patient C
The third patient is a thirty-six year old female that presented to the office for teeth straightening with the Homeoblock appliance. She was treated for thirty months wearing the appliance in the night time only to straighten her upper and lower teeth.
Pre and post profile after six months of treatment
A full face view that superimposes the post face over the pre face photos are used to illustrate where the development took place in the purple color.
Intra oral pre and post photos showing completed treatment with the Homeoblock appliance
Discussion
The issue of facial esthetics and functional orthodontics is very timely. There is a growing focus on esthetics, which needs to be balanced with good functional outcomes. The Homeoblock appliance has several components in combination, including a base-plate with a unilateral bite block and a mid-line expansion screw. We postulate that the unilateral bite block exerts cyclic, intermittent forces on the periodontium of the associated teeth during function (such as swallowing during sleep). These forces are detected by mechanoreceptors on the cell surfaces of the periodontal and periosteal cells. Due to signal transduction(3), a cascade of events is initiated, resulting in gene transcription and mRNA biosynthesis(4). Downstream, osteogenic cells are activated, and adapting to the axial forces, remodeling occurs. The change in vertical dimension (opening the bite) affects also the spatial relations of the contra-lateral teeth(5), which have lost their normal occlusal contacts. These changes are also detected by receptors in their periodontal and periosteal cells. Consequently, remodeling occurs due to signal transduction, adapting to decreased forces in accord with the functional matrix hypothesis(6-7).
The Homeoblock appliance has also a base-plate that does not contact the palatal vault. Consequently, swallowing of saliva creates a relative negative pressure between the palatal mucosa and the fitting surface of the device. As the dorsal surface of the tongue exerts forces on the polished surface of the device during swallowing, tension is exerted on the mucoperiosteum of the hard palate and the midpalatal suture is separated. Thus, the developmental mechanisms of sutural homeostasis are activated(8). Despite the fact that most osteogenic activity is normally observed during early to late childhood, it is now understood that palatal, maxillary and circum-maxillary sutures retain biosynthetic potential into late adulthood (9), and it is possible that mechanical stimuli up-regulate genes that are not typically expressed during normal development(10). It is postulated that the Homeoblock device maintains physiologic forces on the midpalatal suture, resulting in slow expansion (250m per week). Recent research suggests that a sutural width >300m results in bone deposition(11) while a sutural width
2. Singh GD, Diaz J, Busquets-Vaello C, Belfor TR. Soft tissue facial changes following treatment with a removable orthodontic appliance in adults. Funct Orthod. 2004;21(3):18-23.
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3. Sandy JR. Signal transduction. Br J Orthod 1998; 25:269-274.
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4. Mao JJ, Nah HD. Growth and development: hereditary and mechanical modulations. Am J Orthod Dentofacial Orthop 2004;125:676-689.
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5. Iscan HN, Sarisoy L. Comparison of the effects of passive posterior bite-blocks with different construction bites on the craniofacial and dentoalveolar structures. Am J Orthod Dentofacial Orthop 1997;112:171-178.
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6. Moss ML. The functional matrix hypothesis revisited: The role of mechanotransduction. Am J Orthod Dentofacial Orthop 1997;112:8-11.
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7. Singh GD. On Growth and Treatment: the Spatial Matrix hypothesis. In: McNamara JA Jr (ed). Growth and treatment. Craniofacial Growth Series. Monograph 41. Ann Arbor: University of Michigan, 2004.
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8. Mao JJ, Wang X, Mooney MP, Kopher RA, Nudera JA. Strain induced osteogenesis of the craniofacial suture upon controlled delivery of low-frequency cyclic forces. Front Biosci 2003;8:A10-17.
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9. Kokich VC. The biology of sutures. In: MM Cohen Jr (ed). Craniosynostosis: Diagnosis, evaluation and management. New York: Raven Press, 1986.
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10. Mao JJ, Nah HD. Growth and development: hereditary and mechanical modulations. Am J Orthod Dentofacial Orthop 2004;125:676-689.
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11. Borke JL, Yu JC, Isales CM, Wagle N, Do NN, Chen JR, Bollag RJ. Tension-induced reduction in connexin 43 expression in cranial sutures is linked to transcriptional regulation by TBX2. Ann Plast Surg 2003;51:499-504.
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12. Moss ML. The functional matrix hypothesis revisited: The role of mechanotransduction. Am J Orthod Dentofacial Orthop 1997;112:8-11.
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13. Singh GD. On Growth and Treatment: the Spatial Matrix hypothesis. In: McNamara JA Jr (ed). Growth and treatment. Craniofacial Growth Series. Monograph 41. Ann Arbor: University of Michigan, 2004.
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14. Lima AC. Spontaneous mandibular arch response following rapid palatal expansion: a long term study on Class I malocclusion. MS thesis, Marquette University, Milwaukee, Wisconsin, 2004.
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15. Belfor TR, Singh GD. Developing facial symmetry using an intra-oral device. J Cosmetic Dent 2004;20:76-80.
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16 Belfor TR, Singh GD. Developing dental arch symmetry using the Homeoblock device. Int J Orthod 2004;15(3), 27-30.
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17. Singh GD, Diaz J, Busquets-Vaello C, Belfor TR. Soft tissue facial changes following treatment with a removable orthodontic appliance in adults. Funct Orthod. 2004;21(3):18-23.
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18. Belfor TR, Singh GD. Treating malocclusions and improving orofacial form and function in adults. J Amer Acad Gnathol Orthop 2005;22(1), 14-17.
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About the Author: Dr. Theodore R. Belfor graduated from New York University College of Dentistry in 1966 and has been in private practice for 40 years.He has been published in CRANIO, The New York State Dental Journal, Philippine Journal of Orthodontics, Indian Dentist, Dental News (Lebanon), Novoe V Stomatologii (Russia), APEX (UK), The Journal of Cosmetic Dentistry, Aesthetic Dentistry Today, Dentistry Today, The Journal for the American Academy of Gnathologic Orthopedics, The Functional Orthodontist, International Journal for Orthodontics, Sleep Diagnosis and Therapy, Anti-Aging and Cosmetic Surgery Magazine. For more information visit website:
facialdevelopment.com/
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