Written by Theodore R. Belfor, DDS Tuesday, 31 October 2006 19:00
The generation that vowed to stay young forever, the baby boomers, reached 78 million strong in 2005. They are a highly potent economic force, with a strong desire to look and feel the best that they can. We as dental practitioners are in the best position to help them look younger with youthful, attractive smiles and more youthful, attractive faces.
The objective of this article is to discuss the relationship between maxillary development and facial aesthetics in adults. Three cases will be presented that show that facial enhancement can be accomplished by developing the maxilla in adults. A 3dMD facial capture system (3dMDvultus/Kodak) and analytical software are employed to quantify the facial changes. These cases demonstrate that when a functional, orthopedic appliance (Homeoblock [OrthoSmile/Space Maintainers Laboratory]) is worn by adult patients during the nighttime only, it can result in enhanced facial appearance by virtue of wider smiles, straighter teeth, increased midfacial volume, more prominent cheekbones, and stronger appearing jaws.
Maxillary expansion has long been used to correct transverse discrepancies of the maxillary arch using orthopedic, orthodontic, or surgically assisted techniques. Reports on skeletal and soft-tissue changes related to this treatment have been based on 2-dimensional (2-D) data acquired by cephalometrics and 2-D photographic analysis. Studies have shown that maxillary expansion results in skeletal changes involving the maxillary, nasal, zygomatic, and periorbital structures in children.1,2 More recently, maxillary arch size and shape changes as well as facial changes have also been reported in adults.3 Until now there has not been any report on facial soft-tissue changes using 3-dimensional (3-D) data. Stereophotogrammetry for quantifying facial morphology was introduced in the Journal of Dentistry in 1996.4 It was concluded that “stereophotogrammetry is a suitable 3-D registration method for quantifying and detecting development changes in facial morphology.”
Materials and Methods
Figure 1. Histogram showing the distance between 2 surfaces. The red end of the scale shows the most positive distances (ie, those where the post surface is in front of the pre surface); green is the most negative (ie, those where the post surface is behind the pre surface).
After obtaining patient consent, 3-D digital stereophotogrammetry data was collected on patients who were under treatment for teeth straightening with the Homeoblock functional orthopedic appliance. A 3dMD facial capture system was used. This system generates a clinically accurate digital model of the patient’s facial surface. It uses a common technique of stereo triangulation to identify external surface features viewed from at least 2 cameras. This approach incorporates projecting a unique, random light pattern that is used as the foundation for triangulating the geometry in 3-D. The capture takes less than 2 milliseconds per frame. The data is processed creating a highly precise <0.5-mm RMS (root mean squared of the distance measured) digital model of the patient that is ready for immediate clinical use.
Patient photos were recorded at varying treatment intervals. Using software provided by 3dMD, preoperative and postoperative photos were registered, thereby accurately superimposing one facial image over another, allowing for the measurement of changes in volume. These changes in volume can be measured within the software using a color scale (Figure 1).
Treatment and Protocol
Figure 2. The Homeoblock appliance viewed on a plastic model.
Homeoblock treatment began with comprehensive history-taking as well as extraoral and intraoral examinations. Impressions were taken for study models, and digital intraoral and 3-D facial photographs were taken. In addition, digital radiographs were used to evaluate the patients’ facial and jaw development, as a lack of facial symmetry may indicate underdevelopment of the orofacial complex.
The Homeoblock appliance consists of a Hawley arch wire, which extends from the left to the right canine, acting pre-dominantly as a lip bumper. Adams clasps are placed on the bicuspids for retention. The baseplate of the appliance is relieved from the palatal tissues. It incorporates a palatal expansion jack-screw and a unilateral bite block, which is placed on the second bicuspid of the less developed side of the face. Long-arm flap springs gently rest on the anterior teeth (Figure 2). The device is worn at night only. The expansion screw is advanced one turn, equal to 0.25 mm, after 7 days. This expansion rate is considered semirapid maxillary expansion (SRME). It is suggested that dentoskeletal changes after the use of SRME were maintained satisfactorily in the long-term in older adolescents and adults.5 Bird-beak pliers and/or 3-prong pliers are used for adjustment of the clasps. There is no reduction of interproximal enamel.
Each patient wore the Homeoblock appliance initially for 1 week without activation. Three-dimensional facial photographs were taken prior to the appliance being inserted. The appliance was advanced one turn (0.25 mm) after the first week and again each successive week. Each patient was advised to wear the appliance more than 6 hours, but not more than 16 hours, mostly at nighttime. Each patient was seen after 3 weeks, when patient tolerance, fit, and compliance were reviewed. Post-treatment, 3-D facial photographs were taken.
Figure 3. Case 1, pre and post intraoral photos. Homeoblock upper arch treatment was 12 months, with placement of 4 porcelain laminate veneers.
Figure 4. Case 1, pretreatment and post-treatment 3-D facial photos. Note that the eyes are more level, the cheekbones are more prominent, the nasolabial depression has been reduced, and the mouth is wider in the post 3-D photo.
Figure 5. Case 1, 3dMD facial evaluation. Left side: red post-treatment image superimposed over blue pretreatment face in 3-D space. Right side: histogram indicates up to a 1.95-mm increase in the midface.
A healthy 60-year-old female presented for treatment with a strong desire to improve her facial appearance. Her oral hygiene status was good, and there was no active gingival or periodontal disease. Extraoral 2-D and 3-D digital photos, intraoral photos, and cephalometric panoramic radiographs were taken, followed by alginate impressions. A treatment plan using the Homeoblock appliance followed by porcelain laminate veneers was chosen. The patient was under treatment for 8 months before the placement of 4 laminate veneers on teeth Nos. 7 to 10. She then continued treatment with the Homeoblock for a total of 12 months (Figure 3).
The Homeoblock treatment resulted in changes in facial morphology, including a widening of the face, more prominent cheekbones, and a stronger looking jaw (Figure 4). Using 3dMD software systems, the 3-D pretreatment and post-treatment images were registered, overlaying the faces so that the distance between the 2 surfaces, which represents the change in midfacial volume, could be measured. In this case, the software showed as much as a 1.95-mm positive change in the areas of the cheekbones and lower jaw (Figure 5), resulting in a reduction of the nasolabial depression, higher and more prominent cheekbones, and a wider and fuller mouth.
Figure 6. Case 2, pretreatment and post-treatment upper intraoral photos. Note the degree of maxillary expansion without opening spaces between the teeth.
Figure 7. Case 2, pretreatment and post-treatment lower intraoral photos. Note the mandibular development and teeth straightening, followed by placement of a porcelain laminate on tooth No. 24.
Figure 8. Case 2, pretreatment and post-treatment 3-D facial photos. Note the more level eyes, the more prominent cheekbones, the reduction in pouching around the mouth, and the overall enhanced facial symmetry in the post 3-D photo.
Figure 9. Case 2, 3dMD facial evaluation. Left side: red post-treatment image superimposed over blue pretreatment face in 3-D space. Right side: histogram indicates up to a 2.406-mm increase in the midface.
A 50-year-old female, who is a television personality, presented for aesthetic treatment. She had no prior history of orthodontic treatment. Her upper teeth were naturally straight and well aligned. Her lower teeth were crowded, rotated, and required straightening. Facial evaluation showed a premature aging on the patient’s left side. Extraoral 2-D and 3-D digital photos, intraoral photos, and cephalometric and panoramic radiographs were taken, followed by alginate impressions. Upper and lower Homeoblock appliances were designed and fabricated.
After 12 months of treatment, a considerable amount of palatal expansion was accomplished without creating spaces between the teeth (Figure 6). Lower arch development and teeth straightening were accomplished after 24 months with a Home-oblock appliance and the placement of a laminate on tooth No. 24 (Figure 7).
Homeoblock treatment resulted in an enhanced facial appearance, particularly due to a reduction of the aging lines on the left side (Figure 8). An evaluation of the changes in midfacial volume revealed an exceptional increase (Figure 9).
Figure 10. Case 3, pretreatment and post-treatment intraoral photos. Maxillary development and teeth straightening after treatment with the Homeoblock appliance for 9 months.
Figure 11. Case 3, pretreatment and post-treatment 3-D facial photos. Note that the eyes are more level, the cheekbones are more prominent, and there is lip seal in the post-treatment 3-D photo.
Figure 12. Case 3, 3dMD facial evaluation. Left side: red post-treatment image superimposed over blue pretreatment face in 3-D space. Right side: histogram indicates up to a 1.470-mm increase in the midface.
A 21-year-old female presented with concern about her relapsed orthodontic treatment. Her oral hygiene status was good, and there was no active gingival or periodontal disease. Extraoral 2-D and 3-D digital photos, intraoral photos, and cephalometric panoramic radiographs were taken, followed by alginate impressions.
An upper Homeoblock appliance was designed and fabricated. The patient wore the appliance for 9 months. Dental arch development resulted in straighter teeth (Figure 10). Facial evaluation showed an establishment of lip seal and filling out of the upper lip (Figure 11). In evaluating midfacial change, it appears that the patient underwent horizontal development in the lower third of the face, with up to a 1.470-mm increase in the perioral region (Figure 12).
The Homeoblock appliance produces significant facial changes while worn only at night. The physiological response to wearing the appliance appears to continue during the daytime hours when there is no appliance in place, to be reinforced when the appliance is once again worn the following night. Preliminary studies 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.6 Due to signal transduction, a cascade of events is initiated, resulting in gene transcription and mRNA biosynthesis.7 Downstream osteogenic cells are activated, and, adapting to the axial forces, remodeling occurs. The change in vertical dimension (removing tooth contact) also affects the spatial relations of the contralateral teeth,8 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.
The Homeoblock appliance also has a baseplate 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.9 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 adult-hood,10 and it is possible that mechanical stimuli activate genes that are not typically expressed during normal development.11 It is postulated that the Homeoblock device maintains physiologic forces on the midpalatal suture, resulting in slow expansion (250 µm per week).
Recent research suggests that a sutural width greater than 300 µm results in bone deposition,12 while a sutural width less than 300 µm is thought to arrest bone deposition and/or initiate bone resorption. Thus, Homeoblock-induced mechanotransduction may result in remodeling activities that affect facial morphology. The net results of this protocol are thought to evoke the maxillo-mandibular spatial patterning that is encoded at the level of the genome.
According to the functional matrix hypothesis,13,14 the mandible and mandibular dentition form a spatial matrix15 that is responsive to the maxillary complex. The unilateral bite block of the Homeoblock appliance activates the lateral pterygoid muscles that displace the mandible anteriorly and inferiorly, providing space for putative condylar remodeling. Therefore, it is conceivable that during the correction of palato-maxillary structures, the Homeoblock appliance will produce spontaneous correction of the mandible16 due to neuromuscular activity. Simultaneously, the baseplate of the Homeoblock appliance displaces the tongue anteriorly and inferiorly so that it contacts the lower anterior teeth intermittently. These neuromuscular responses may aid in relieving lower incisor crowding in conjunction with the mandibular expansion screw, while the flap springs aid in the correction of the spatial alignment of the mandibular dentition. Therefore, the ultimate result of the Homeoblock device is thought to evoke enhanced symmetrical dentofacial development17,18 that is genetically encoded for each individual.
Further studies are being planned to monitor these preliminary findings using a larger sample of adult patients on a long-term basis, deploying a randomized clinical trial design.
1. Snodell SF, Nanda RS, Currier GF. A longitudinal cephalometric study of transverse and vertical craniofacial growth. Am J Orthod Dentofacial Orthop. 1993;104:471-483.
2. Berger JL, Pangrazio-Kulbersh V, Thomas BW, et al. Photographic analysis of facial changes associated with maxillary expansion. Am J Orthod Dentofacial Orthop. 1999;116:563-571.
3. Singh GD, Diaz J, Busquets-Vaello C, et al. Facial changes following treatment with a removable orthodontic appliance in adults. Funct Orthod. 2004;21:18-23.
4. Ras F, Habets LL, van Ginkel FC, et al. Quantification of facial morphology using stereophotogrammetry: demonstration of a new concept. J Dent. 1996;24:369-374.
5. Iseri H, Ozsoy S. Semirapid maxillary expansion--a study of long term transverse effects in older adolescents and adults. Angle Orthod. 2004;74:71-78.
6. Sandy JR. Signal transduction. Br J Orthod. 1998;25:269-274.
7. Mao JJ, Nah HD. Growth and development: hereditary and mechanical modulations. Am J Orthod Dentofacial Orthop. 2004;125:676-689.
8. 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.
9. Mao JJ, Wang X, Mooney MP, et al. Strain induced osteogenesis of the craniofacial suture upon controlled delivery of low-frequency cyclic forces. Front Biosci. 2003;8:A10-A17.
10. Kokich VG. The biology of sutures. In: Cohen MM Jr, ed. Craniosynostosis: Diagnosis, Evaluation, and Management. New York, NY: Raven Press; 1986.
11. Mao JJ, Nah HD. Growth and development: hereditary and mechanical modulations. Am J Orthod Dentofacial Orthop. 2004;125:676-689.
12. Borke JL, Yu JC, Isales CM, et al. Tension-induced reduction in connexin 43 expression in cranial sutures is linked to transcriptional regulation by TBX2. Ann Plast Surg. 2003;51:499-504.
13. Moss ML. The functional matrix hypothesis revisited: The role of mechanotransduction. Am J Orthod Dentofacial Orthop. 1997;112:8-11.
14. Singh GD. On growth and treatment: the spatial matrix hypothesis. In: McNamara JA Jr, ed. Growth and Treatment: A Meeting of the Minds. Ann Arbor: University of Michigan; 2004. Craniofacial Growth Series, Vol 41.
15. Singh GD, Clark WJ. Localization of mandibular changes in patients with class II division 1 malocclusions treated with twin-block appliances: finite element scaling analysis. Am J Orthod Dentofacial Orthop. 2001;119:419-425.
16. Lima AC, Lima AL, Filho RM, et al. Spontaneous mandibular arch re-sponse after rapid palatal expansion: a long-term study on class I malocclusion. Am J Orthod Dentofacial Orthop. 2004;126:576-582.
17. Belfor TR, Singh GD. Developing facial symmetry using an intra-oral device. J Cosmetic Dent. 2004;20:76-80.
18. Belfor TR, Singh GD. Treating malocclusions and improving orofacial form and function in adults. J Am Acad Gnathol Orthop. 2005;22:14-17.
Disclosure: Dr. Belfor is chairman and president of OrthoSmile and inventor of the Homeoblock appliance.
- Clinical Update
- CE Articles
- Dental Materials
- Dental Medicine
- Digital Impression Technology
- Forensic Dentistry
- Geriatric Dentistry
- Infection Control
- Interdisciplinary Dentistry
- New Directions
- Practice Management
- Oral Cancer Screening
- Oral Medicine
- Oral-Systemic connection
- Pediatric Dentistry
- Pain Management
- Post-and-Core Technique
- Sleep Disorders
- Sports Dentistry
- Technique of the Week
- Treatment Planning