April 1, 2013
by Howard Golan, DDS
Fixed partial dentures, whether using tooth as abutments or implants as abutments, are one of the most productive and widely completed procedures in dentistry.
One of the challenges in this procedure is the design of the pontic sites. In dental school dental students are taught various designs for pontics. Ridge lap, hygienic, and ovate are some of those designs.
It is apparent that the ridge lap is the most widely used pontic design. Most clinicians do not specify to the laboratory what design to use so the lab takes it upon themselves to design the pontic sites. It is the easiest to fabricate, it can be manipulated to get good esthetics and it is the easiest for the clinician to manipulate in the mouth. Thus the ridge lap is the most ubiquitous design for pontics.
However, the ovate pontic site is a better design for function and esthetics. The ovate site creates an emergence profile that better mimics how a natural tooth emerges from beneath the gingival tissues. The ovate site eliminates food impaction and patients predictably report excellent esthetics with this design.
Traditionally most restorative clinicians avoid this design because of increased work flow. Potential surgical procedures by the clinician or a specialist, added visits and time between procedures, all create a negative reputation for this design. Clinicians do not often see the value to adding this design to their fixed partial dentures.
The ovate pontic site can be created in two ways. First, and most optimal is when a tooth is extracted, an ovate pontic is relined into the healing socket. As the gingival tissues heal, it will heal around the ovate pontic.
The second and more common situation in when a replacement FPD is contemplated or when the edentulous site is long standing. Here an ovate site is created in the soft tissue. This requires a surgical procedure. This concave site in the gingiva can be created by a bur, scalpel or electro-surgery. Many times restorative clinicians would refer this procedure to a periodontist.
Once the gingiva is resected, inflammation and remodeling requires the clinician to wait for the tissue to mature before placing porcelain on the framework to reline the newly formed site. This could take weeks. Furthermore, a surgical procedure is not always a positive experience for the patient. Patients may not want to do this procedure if, they have to go to the specialist, significant cost is added, and possible pain, are associated with this procedure.
Lasers have been used in dentistry for decades. However the past decade has seen an explosion in the integration of lasers in dentistry. Lasers cut soft tissue efficiently, minimal bleeding and the healing after these procedures are unmatched. Diode lasers, typically with wavelengths between 800-1000nm, have led the explosion. They are small, easy to use and relatively inexpensive. Thus clinicians use diode lasers to cut soft tissue and this type of laser can be used to create an ovate pontic site.
However, diode lasers, though a good soft tissue laser, cut with heat. Heat on tissue creates its own problems. Especially in esthetic areas, burning or charring tissue can cause pain, recession, and requires healing time before remodeling.
Since the 1990s, the ErCr:YSGG laser (Waterlase, Biolase Technology, Irvine, CA), has been used to cut not only soft tissue but dental hard tissue as well. This laser seeks water in tissue and uses water to create a cooler cut. It therefore does not carbonize tissue and thus thermal effects are minimized.
Cutting with water provides a clinician with a unique opportunity to manipulate tissue without the negative thermal effects associated with heat cutting lasers (Diodes, Nd:YAG, CO2). The limited thermal effects minimize the cell damage to the remaining tissue adjacent to the cut. This reduces the inflammatory response and thus reduces the remodeling needed during healing. Therefore, the clinician can feel confident that the day they create the ovate site they can reline both the framework and the provisional without any concern of poor adaptation to the tissue.
Water assisted cutting also allows the procedure to be done with topical anesthetic or many times no anesthetic at all. Better healing and no traditional injection makes this procedure very well accepted by the patient.
Previously, many fixed partial dentures were cemented provisionally, allowing the clinician and the patient to function with it to ensure an esthetically acceptable design and that there is no food impaction. Ovate pontic designs essentially eliminate this step because there is no food impaction and the emergence profile created makes the pontic look like it is a tooth emerging from its periodontal site.
Economically, this laser assisted procedure is a billable procedure and it is offered to all patients with fixed partial dentures. This procedure was mainly done in esthetic areas but now due to all the positive feedback with the esthetics and function, the ovate pontic is offered both in esthetic and non-esthetic areas.
The abutments are prepared either with FPD preparations or if implants, the abutment level is fabricated. The FPD is impressed and the laboratory will fabricate the framework with the knowledge of an impending ovate pontic.
The ovate is prepared with an ErCr:YSGG laser typically at a setting of 4.5w 35water 40air with a frequency of 50Hz. The area is given a topical anesthetic, Cetacaine (Cetylite Industry, NJ). The laser prepares a concavity with the B-L width determined by the intended width of the emergence profile of the tooth to be simulated. The framework is in place for much of the procedure as it gives a visual guide. Typically the site is prepared to a depth of 2-3mm to give the laboratory enough room to create the proper emergence. The framework is then removed and the final shape of the ovate site is created. A “Laser Bandage” is created if any hemostasis is need.
The framework is replaced and the pontic is relined with acrylic resin. The resin is carefully sculpted to simulate the future porcelain.
The framework is picked up in an impression and the lab will place the porcelain on the framework.
The ovate pontic site is a wonderful adjunct to the FPD procedure. It is efficient, profitable and improves the esthetics and function for the patient. The Erbium laser can do this procedure with no discomfort, minimal bleeding and no additional visits and time between these visits.OH
Dr. Howard Golan is a graduate of the University of Michigan School of Dentistry. He is the co-founder of the Center for Laser Education and is a faculty member with the World Clinical Laser Institute teaching Certification Training Courses for that organization. Dr. Golan has instituted CAD/CAM technology into his practice for four years and has lectured on the subject. He is a graduate of the Alleman Center for Biomimetic Dentistry. Dr. Golan’s excels in teaching quick and productive integration of laser-assisted dentistry, minimally invasive concepts and CAD/CAM technology into dental practices. Dr. Golan practices and teaches a Biomimetic philosophy and is passionate about conserving tooth, soft tissue and bone.
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