Recent advances in laser and CAD/CAM technology have opened the doors to both patients and clinicians, offering minimally invasive and timely delivery of acceptable dental restorations, often in “same day” timelines. Application of current bonding methodologies with less-than-ideal remaining tooth structure has allowed practitioners to restore compromised dentition while achieving their final desired position, color, and shape.
There are many significant advantages to restoring dentition with conservative and minimally invasive techniques. These include a reduced need for anesthesia, the absence of postoperative sensitivity, secure bonding to the remaining enamel, reduced flexing stress, the potential for reversal of treatment, and higher treatment acceptance. In such instances, case selection is extremely important. Prior to advising patients of any treatment option, the clinician should perform a thorough medical history evaluation and a clinical examination, including photographs, radiographs, periodontal evaluation, mounted models and patient interview. A comprehensive review of hard and soft tissue structures is also required. In addition, the patient’s craniomandibular status as it applies to TMJ/TMD must be documented to effectively prepare a treatment plan that ultimately leads to harmonious dental/alveolar function. Only following this comprehensive review of the patient’s current condition can the practitioner determine the options available to achieve the final restorative results. The clinician should then select the least invasive modaility to achieve the desired clinical outcome. This article will demonstrate how laser and CAD/CAM technologies may be utilized to create these desired results in a manner that is minimally invasive and in a reduced number of office visits.
Patient History and Examination
A 47-year-old male patient sought treatment for a chief complaint of worn dentition and sensitivity to chewing and drinking liquids. Upon clinical examination, the authors noted severe erosion on all occlusal surfaces (Figures 1 and 2). The patient attributed this to “sucking on lemons” for over 17 years. This acid erosion was devastating to the hard tooth structures and, due to the prolonged exposure to this habit, a decrease in pH led to severe erosion.1,2
Upon review of a full-mouth radiographic series, no decay or pulpal pathology was noted. Periodontal probings were all within normal limits with pocket depths of 2 mm to 3 mm, generally without bleeding. There were no soft tissue lesions noted. The patient’s previous dental history was unremarkable with only a few remaining amalgam restorations present
During the course of examination,3 it was also noted that the patient had multiple pain responses to head, neck, and jaw joint palpations, which led the clinicians to suspect an underlying TMJ/TMD condition. Obvious loss of vertical dimension and lower anterior facial height can lead to craniomandibular dysfunction. To determine the severity of this patient’s TMJ condition, both polar and axial corrected tomography were performed to assess the pretreatment condylar condition.4 Using these films to document pretreatment status, facebow mountings of diagnostic models were assembled. All muscles of mastication were examined by digital palpation and the results were also documented. Many other principles were involved in the authors’ establishment of the appropriate dental/alveolar relationship; those are, however, beyond the scope of this article and therefore not discussed here.
Fabrication of Provisional Restorations
A diagnostic waxup of the proposed new relationship of the maxillary and mandibular arches was completed, taking into account the following elements: the occlusal plane, the appropriate dental/alveolar overjet and overbite relationship, the standard height, shape and size ratios for both dentition and lower anterior facial height. These elements were used to follow and accommodate arch width and space availability of this patient. These models were then sent to the laboratory for acrylic duplication and fabrication of provisional restorations.2 The latter were made to be placed over the remaining eroded dentition so that the patient could have an immediate provisional occlusion. The patient was recalled four times in a six-month period to follow progress. By placing these provisional restorations, the patient demonstrated clinical reductions in head, neck, and mandibular joint pain, and gained the ability to masticate and function within a more normal range of motion.
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Preparations of Teeth Using a Er,Cr:YSGG Laser
All 28 teeth were prepared utilizing a hard tissue laser (Er,Cr:YSGG) exclusively.5,6 Using quartz laser tips at 5.25 W of power, 25 Hz, 60% air and 30% water, the peripheral rim of enamel was exposed (Figure 3). This allowed for the visualization of the DEJ, where the authors could then direct the energy of the laser to remove enamel gingivally to the depth needed to create a shoulder margin, which is ideal for CAD/CAM restorations. This step cleaves the enamel from the dentin interface, preparing the axial walls of the preparation. When preparing teeth for crowns/overlays with the laser, the power to reduce the tooth structure may vary for each tooth, depending on how much enamel is present, its thickness, and where the gingival third begins for each tooth. The authors’ power settings for the proximal reduction averaged 3.25 W, 25 Hz, 60% air, 30% water, with a 500-µm quartz tip. The margination process was completed using a higher pulse rate of 50 Hz, lower power (ie, 0.75 W to 1 W), 600-µm quartz tips, with 60% air, 30% water ratios. Since lower energy was required to prepare these teeth, local anesthetic was unnecessary.7,8 These settings created a very smooth preparation and very readable margins (Figure 4).
CAD/CAM Fabrication of Restorations
As the patient resided a great distance from the dental office, the authors were limited as to the number of visits possible in order to follow progress. These conditions made this patient an ideal candidate for restorative treatment via CAD/CAM dentistry because the restorations could be milled and bonded on the same day as the preparation.
After preparing all maxillary and mandibular remaining dentition, CAD/CAM principles were applied to create the definitive restorations.9,10 The severe erosion and loss of anterior vertical dimension observed pretreatment were addressed via the custom acrylic provisional restorations, which the patient had worn for six months.
In order to complete this full-mouth restorative case, the team divided the CAD/CAM approach into two visits, beginning with the maxillary arch. Leaving the provisional temporarily in place, the authors first captured an image of each temporary crown with the infrared camera acquisition unit of the CAD/CAM. After preparing through the acrylic temporary—alternating with every other tooth—the necessary images were captured and the restorations were designed on the computer. Following milling, staining and glazing of the porcelain crowns, they were permanently bonded. This process was repeated to prepare the remaining maxillary teeth utilizing the remaining provisional restorations. Images were captured again, and the definitive crowns were fabricated and permanently bonded.
Upon completion of the maxillary arch, the patient was dismissed and asked to return the following day for completion of the mandibular arch. Following removal of all but the two most posterior temporary crowns (#18 and #31), all the teeth from the first molars and forward were prepared. Teeth #18 and #31 were left untouched to function as vertical index stops. The same sequence was repeated for every other tooth. Once milling and glazing were complete and the definitive crowns placed, the same process was then completed for teeth #18 and #31 (Figures 5-6-7-8-9).
By combining two relatively new dental treatment modalities (lasers and CAD/CAM technologies), it was possible to rehabilitate this patient’s dentition and dental health. The authors demonstrated that this restorative case could be completed in fewer office visits without the use of the conventional handpiece, no local anesthetic, and implementing same-day milled ceramic restorations. The authors believe that with continued improvements, this treatment delivery system will become more widely used in the dental population.
The authors mention their gratitude to Biolase Technologies, Inc, and Patterson Dental for their material contributions to this case. Drs. Colonna and DiVito receive honoraria from Biolase Technologies for speaking on laser dentistry at various dental meetings.
* Private practice, Whitefish, MT; Adjunct Faculty, Arizona School of Dental Oral Health, Phoenix, AZ.
† Private practice, Scottsdale, AZ; Adjunct Faculty, Arizona School of Dental Oral Health, Phoenix, AZ.
‡ Laboratory technician, Spokane, WA.
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