CHAPTER 8
ATLAS OF CLINICAL PROCEDURES
MACIEJ ŻAROW
Are porcelain veneers a challenge for the dentist in terms of comprehensive esthetic treatment, ensuring the patient beauty and harmony of life? Probably yes, but in most cases, it depends on following the rules that will lead to success.
Atlas of clinical procedures
In hundreds of clinical situations that I have encountered in everyday practice, one can find an extensive set of experiences, regularities, and rules that allow the formulation of effective treatment procedures for porcelain veneers. This chapter will help you understand how to proceed in different clinical situations to accomplish the planned treatment.
VENEERS AND TEETH WITH MULTIPLE DIRECT RESTORATIONS
It can be assumed that the larger the tooth surface area covered by composite restorations, the worse the prognosis will be for porcelain veneers. On the other hand, it is difficult to find ideal cases for veneers in everyday practice as those often shown in books, at lectures by famous dentists, or in advertising brochures. In everyday practice, the dentist expects the dental technician’s help by fabricating porcelain veneers in cases where it is difficult to perform perfect restorations due to their number, shape, or match the color to the adjacent teeth. It can be assumed that veneers can be performed when more than 50% of the tooth structure remains after preparation.1
Of course, the more structure of the tooth is present, the more predictable veneer will be. The more enamel remains on the preparation margin, the better the future veneer adhesion and its final prognosis.2–4 All this should be properly explained to the patient. After that conversation, a final, well-thought-out decision should be made about whether to remake only the previous restorations, perform porcelain veneers, or maybe decide on more invasive treatment, like all-ceramic crowns.
The principle is simple: the quantity and quality of the tooth structure contribute to good adhesion and prognosis of the veneer. The lack of predictable adhesion prompts us to plan indirect restorations based on mechanical retention, such as prosthetic crowns.
RULES WHEN PERFORMING VENEERS ON TEETH WITH MULTIPLE COMPOSITE RESTORATIONS
1. Replacement of all leaking and “suspicious” restorations with new ones
2. Tooth whitening has to be carried out at least 1 month before the planned treatment so that the color of the veneer can be matched to the new, stable one and also allow the bonding system to have optimal adhesion to the tooth
3. In the case of an extensive composite restoration on the proximal surface, preparation should include the entire contact surface in order to cover the composite resin with the indirect veneer5,6
4. In the juxtagingival area, the preparation margin should not “meet” the composite resin restoration (what is acceptable in the case of posterior indirect partial restorations)
REMEMBER
Do not hesitate to replace all the restorations that do not meet the appropriate marginal adaptation standards. Leaving leaking composite resin under the veneer can cause discoloration, inflammation of the gums, or weakening of the final veneer adhesion …
Case 1: Veneers and teeth with multiple composite restorations
A 33-year-old female patient presented to the dental office seeking porcelain veneers for her anterior maxillary teeth. The patient did not like the color of her teeth and the occurrence of many composite restorations that became discolored over time.
Fig 8-1a
Patient’s smile before starting the treatment.
Fig 8-1b
Location of the incisal edges of the maxillary teeth in relation to the upper lip in repose.
Figs 8-1c and 8-1d
Intraoral photographs of the anterior teeth – extensive composite restorations are clearly visible.
Fig 8-1e
Situation after teeth whitening and replacing the restorations.
Fig 8-1f
Porcelain veneer preparation from a mock-up level, created on the basis of the diagnostic wax-up.
Fig 8-1g
Initial preparation on the labial surface shows the extension of Class 3 and 4 restorations in teeth 12, 11, 21, and 22.
Fig 8-1h
Anterior teeth – palatal view.
Fig 8-1i
Depth of the preparation was controlled with a silicone index made on the basis of the diagnostic wax-up model.
Fig 8-1j
Clinical situation after veneer preparation on teeth 13–23. Note: preparation on tooth 12 mesial, 11 mesial and distal, 21 mesial and distal, and 22 mesial was extended to the proximal surface.
Fig 8-1k
Feldspathic porcelain veneers 13–23 were fabricated in the dental laboratory.
Fig 8-1l
Teeth 11 and 21 etched with phosphoric acid in rubber dam isolation.
Fig 8-1m
Situation after etching the teeth surface …
Fig 8-1n
… and after application of the bonding system and polymerization.
Fig 8-1o
Simultaneous cementation of two veneers on teeth 11 and 21.
Fig 8-1p
Removing polymerized composite resin excess with a scalpel no. 12.
Fig 8-1q
Situation after cementation of two porcelain veneers in rubber dam isolation and removing the excess material.
Fig 8-1r
Integration of the porcelain veneers with gingival tissues a few weeks after cementation.
Fig 8-1s
Color compatibility with the remaining teeth of the maxillary and mandibular arches.
Figs 8-1t to 8-1v
Patient’s smile: perfect integration with the upper and lower lip.
Fig 8-1w
Clinical follow-up 6 years after veneers cementation.
Fig 8-1x
Clinical situation 6 years after veneers cementation – palatal view.
Case 2: Veneers on the teeth with multiple composite restorations, 25-years follow-up
How long can veneers last? Dentists and patients often ask this question. A 25-year observation of porcelain veneers performed on teeth with multiple,
extensive restorations is presented below. Follow-up over 25 years showed perfect integration of the veneers with tooth structure, soft tissues, and esthetic harmony with the patient’s smile. This case shows that following strict adhesion procedures can lead not only to great esthetic results, but also to long-lasting restorations.
(With permission of Dr. Marco Nicastro)
Fig 8-2a
A 27-year-old female patient with extremely unesthetic old restorations presented to the office seeking esthetic treatment.
Fig 8-2b
Clinical situation before treatment.
Figs 8-2c and 8-1d
Close-up of the discolored restorations in the maxillary arch.
Fig 8-2e
Radiographs showing the extension of composite restorations.
Fig 8-2f
After removing the old restorations in teeth 11 and 12 – palatal view.
Fig 8-2g
After replacing the restorations with new ones – palatal view.
Fig 8-2h
Clinical situation after replacing the old composite restorations.
Fig 8-2i
Clinical situation after teeth preparation. Note: The proximal surfaces with extensive composite restorations are included in the preparation to allow them to be covered with porcelain.
Fig 8-2j
After taking the impressions, provisional veneers were placed to protect the teeth.
Fig 8-2k
Feldspathic porcelain veneers were fabricated in the dental laboratory.
Fig 8-2l
After the try-in and acceptance of the veneers, adhesive cementation was obtained in the isolation of a rubber dam.
Fig 8-2m
Porcelain veneers were cemented individually with a dual-cure luting cement (restorations made 25 years ago).
Figs 8-2n and 8-2o
Clinical situation (n) before and (o) after treatment with porcelain veneers.
Figs 8-2p and 8-2q
Clinical situation (p) before and (q) after treatment – palatal view.
Figs 8-2r and 8-2s
Anterior teeth (r) before and (s) after treatment.
Figs 8-2t and 8-2u
Patient’s smile (t) before and (u) after treatment.
Figs 8-2v and 8-2w
Patient’s smile from the (v) right and (w) left semi-profile.
Fig 8-2x
Radiographs after porcelain veneers cementation.
Fig 8-2y
Clinical situation 10 years after porcelain veneers cementation.
Fig 8-2z
Patient’s smile 10 years after porcelain veneers cementation.
Fig 8-2aa
Clinical situation 25 years after porcelain veneers cementation (in the meantime, the patient lost a tooth in the mandibular arch, and the prosthetic restoration in the mandible was replaced).
Fig 8-2bb
Patient’s smile 25 years after porcelain veneers cementation.
VENEERS AND DISCOLORED TEETH AFTER ROOT CANAL TREATMENT
A discolored tooth after root canal treatment poses a serious challenge for the dentist. Of course, it would be best to whiten it internally using the walking bleach technique, and then choose the type of treatment,7–9 but bleaching is not always possible due to:
Subgingival microcracks (risk of external cervical resorption)
Post and core in the root canal (risk of additional loss of hard substance when removing the post)
Risk of tooth fracture or perforation related to the removal of old restorative material located in the pulp chamber
Major tooth damage in the cervical area9
If there is even a slight chance to change the color of the tooth to a brighter one, take advantage of bleaching – a dental technician will have a much easier task when they do not have to use a masking opaque material for tooth discoloration. The greater the masking of the discoloration, the more “opaque” the veneer will look without letting light inside the tooth, which may lead to the impression of an “artificial” restoration.
Extensive discoloration is often associated with extended preparation of the tooth, because the dental technician will need more space to cover the discoloration. However, the deeper and more extended the preparation, the bigger the risk of exposing the dentin, which will negatively impact the future durability of the veneer adhesion and reveal an even darker layer of the tooth (dentin is darker than enamel).
In order to minimize the preparation, it is best to plan enlargement of the tooth labial volume with the mock-up.10–11 If the additive mock-up is accepted, we gain 0.2–0.4 mm before the beginning of the preparation, which is crucial for the dental technician in order to cover the discoloration. This procedure significantly enhances the chance of enamel preservation during the preparation.
“Additive” veneers, ie, enlarging the labial volume of the tooth, have completely changed the approach to tooth preparation planning. In the past, in the case of discoloration, the veneer preparation performed by the dentist was supposed to be deep. By “entering” the dentin with the bur, the dentist unconsciously exposed the dark tooth structure, so the dental technician faced an even greater challenge to mask the discoloration with the restoration.
RULES WHEN PERFORMING VENEER ON DISCOLORED TOOTH AFTER ROOT CANAL TREATMENT
1. Consider internal bleaching to change the color of the tooth to a brighter one (always remember about the contraindications for whitening!)9,12
2. When a decision is made to perform a veneer on the discolored tooth, plan two symmetrical veneers (this will reduce the risk of esthetic failure, and less of the discolored tooth structure will be removed due to additive veneers fabrication)13
3. Avoid single veneer preparation13
4. Check with a mock-up whether it is possible to enlarge the labial volume and extend the incisal edge; if so, the preparation will be less invasive10,11
5. The preparation should always be performed from the mock-up level10,11
6. Avoid exposing the dentin, so the dark layer of the tooth is not revealed and the durability of the veneer adhesion with the tooth structure is not weakened.
REMEMBER
Paradoxically, when performing two veneers, we remove less hard tissues than in the case with one veneer – because by planning two symmetrical veneers, it is possible to symmetrically increase their external volume. It will also be much easier for a dental technician to achieve the desired esthetic result. We often pander to patient pressure by making one asymmetrical veneer – which significantly increases the risk of esthetic failure.
Discolored tooth after root canal treatment is difficult to treat, especially when the discoloration includes the incisal edge …
Case 3: Discolored tooth after root canal treatment with contraindication for internal bleaching
A 31-year-old patient presented to the dental office to improve the esthetics of tooth 11 (Figs 8-3a to 8-3d). The tooth was significantly discolored due to trauma and pulp necrosis many years ago. In the past, tooth 11 had root canal treatment and a fiberglass post was cemented (Fig 8-3c), which disqualifies internal bleaching. It is unreasonable to take the structural risk by removing the fiber post and composite resin from the tooth chamber. This can result in additional tooth structure loss and the risk of creating cracks or fractures. The patient was offered treatment with two porcelain veneers on the central maxillary incisors (Fig 8-3e). For this purpose, a diagnostic wax-up was created and a mock-up based on it (Figs 8-3f to 8-3h), which was presented to the patient by means of photographs.
Fig 8-3a
Extraoral photograph with lips in repose – taken to assess the current position of the incisal edges of the maxillary teeth in relation to the upper lip.
Fig 8-3b
Discolored tooth 11. Intraoral photograph in the position of maximum intercuspation.
Fig 8-3c
Radiograph of tooth 11: visible root canal filling and fiberglass post slightly deviating from the root canal axis.
Fig 8-3d
Discolored tooth 11. Intraoral photograph taken in the anterior guidance.
Fig 8-3e
Digital Smile Design (DSD) planning of the new shape of the teeth to transfer information to the dental laboratory and perform a mock-up.
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Video: Performing mock-up https://books.dentist.com.pl/veneers/video/18 |
Figs 8-3f to 8-3h
Photographs of the patient’s smile with a mock-up made according to DSD and diagnostic wax-up. Thanks to the photographs, the patient can see the visualization of the treatment plan integrated into his full face and smile.
Why was it indicated to cover two central incisors symmetrically with veneers in this case?
Performing two symmetrical veneers increased the chance of esthetic success (it is more difficult to notice the difference when two veneers are covering the teeth symmetrically).
Planning veneers that are slightly bigger than the current size of the teeth made it possible to minimize the depth of preparation.
By fabricating two symmetrical restorations, it was possible to obtain a more predictable bond strength for the veneer (exposure of the dentin was significantly reduced).
At the next appointment, veneer preparation was performed on teeth 11 and 21 through the mock-up (Fig 8-3i), which minimized the final tooth preparation. The preparation was controlled with a silicone index cut in two planes: horizontal to control the depth of preparation at different zones of the buccal surface (Figs 8-3j and 8-3k) and vertical to control the incisal reduction (Fig 8-3l).
Fig 8-3i
Mock-up was applied with a silicone index directly before the preparation. (Mock-up is always supposed to be a starting point for minimally invasive veneer preparation.)
Fig 8-3j
Controlling the preparation depth with a silicone index.
Fig 8-3k
Silicone index cut in “harmonica,” making it possible to control the preparation depth on the labial surface at different levels.
Fig 8-3l
Controlling the space for the porcelain at the incisal edge.
The final preparation was obtained after inserting the #000 retraction cord, followed by placing a second #00 cord impregnated with Astrident (Fig 8-3m). After taking the impressions for porcelain veneers and opposite dental arch, the facebow registration has taken. Next, the teeth were covered with provisional veneers (Fig 8-3n). Their retention was ensured thanks to their mutual connection on the proximal surfaces and temporary resin mechanical interlock in the interdental spaces. The final feldspathic porcelain veneers were made in the dental laboratory. The dental technician obtained an excellent esthetic effect by blocking the discoloration from the inside of the veneer and additional external staining. After try-in with glycerin gel (Fig 8-3o), the veneers were adhesively prepared and cemented in rubber dam isolation. The final esthetic outcome and integration with the soft tissues were assessed a few weeks after cementation (Figs 8-3p to 8-3t). A comparison of the clinical situation and the patient’s smile before and after treatment is presented in Figs 8-3u to 8-3x. Clinical follow-up after 4 years showed a perfect esthetic and biological integration of the veneers (Fig 8-3y).
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Video: Preparation through the mock-up https://books.dentist.com.pl/veneers/video/19 |
Fig 8-3m
Final veneer preparation on teeth 11 and 21 with retraction cords before an impression with a polyvinyl siloxane material.
Fig 8-3n
Provisional veneers on teeth 11 and 21.
Fig 8-3o
Feldspathic veneers try-in with glycerin gel to simulate the final color that will be achieved after cementation.
Fig 8-3p
Final esthetic outcome 3 weeks after veneers cementation.
Fig 8-3q
Semi-profile intraoral photograph showing the perfect soft tissue integration and masking previous discoloration (laboratory work: DT Artur Nyga).
Fig 8-3r
Intraoral photograph from the palatal view – visible palatal margin of the veneer with a butt joint preparation, without interfering with the concave part of the palatal surface.
Figs 8-3s and 8-3t
Patient’s smile 3 weeks after veneers’ cementation.
Figs 8-3u and 8-3v
Photographs of the patient (u) before and (v) after porcelain veneer treatment.
Figs 8-3w and 8-3x
Intraoral photographs of discolored tooth 11 (w) before treatment and (x) after veneer cementation.
Fig 8-3y
Clinical follow-up 4 years after veneers cementation.
Case 4: Endodontically treated discolored tooth with contraindication for internal bleaching
A 37-year-old female patient presented to the dental office in order to improve the esthetics of her maxillary incisors due to tooth discoloration (tooth 11) and unpleasant restorations in the adjacent teeth (Figs 8-4a to 8-4f). Tooth 11 had a fiberglass post, placed many years ago, which is a contraindication for internal bleaching. As in Case 3 (see Fig 8-3), the structural risk of removing the old post was relatively high. The patient’s tooth restorations had been replaced many times in the past. She wanted to achieve an equally esthetic and durable effect; therefore, teeth 12–22 were qualified for porcelain veneers.
Fig 8-4a
Patient’s lips in repose: significant exposure of the front teeth makes tooth discoloration uncomfortable for the patient.
Fig 8-4b
Right semi-profile view of the teeth, upper and lower lip in repose.
Figs 8-4c and 8-4d
Intraoral photographs of discolored maxillary anterior teeth: tooth 11 after root canal treatment; teeth 12, 21, and 22 with vital pulp, but their composite restorations need to be changed.
Fig 8-4e
Clinical situation prior to treatment – palatal view.
Fig 8-4f
Radiograph of tooth 11 after previous endodontic treatment: a visible fiberglass post is a contraindication for internal bleaching.
Teeth were externally bleached in a conventional way (overnight whitening). Then composite restorations with marginal leakage and discoloration were replaced, and a Class 3 cavity in tooth 12 was prepared and filled (Figs 8-4g to 8-4j). Next, based on the diagnostic wax-up, a mock-up was made and, using photographs, the proposed changes were shown to the patient (Figs 8-4k and 8-4l). After the treatment plan acceptation, the mock-up through preparation was performed (Figs 8-4m and 8-4n) to reduce the tooth preparation to the necessary minimum.
Fig 8-4g
Patient’s smile after conventional, overnight tooth whitening and replacing the leaking restorations.
Figs 8-4h and 8-4i
Patient’s smile from the (h) left and (i) right semi-profile after conventional overnight tooth whitening and replacing the leaking composite restorations.
Fig 8-4j
Intraoral photograph after conventional overnight tooth whitening and replacing the leaking composite restoration.
Fig 8-4k
Patient’s face and smile before treatment.
Fig 8-4l
Patient’s face and smile after placing the mock-up on the anterior maxillary teeth (12–22).
Figs 8-4m and 8-4n
Veneer preparation through the mock-up – in this way, the tooth preparation is reduced to the necessary minimum.
Due to minor protrusive inclination of the maxillary incisors, control photographs of the prepared teeth were taken. Their relationship to the lower lip was analyzed so that the dental technician has enough space for the adequate profiling of the incisal part of the veneer (the incisal edge should reach the vermilion border of the lower lip during the phonetic tests; Fig 8-4o).
Fig 8-4o
Due to the relative protrusion of the maxillary incisors, their position was assessed in relation to the lower lip during the preparation, so the dental technician will have enough space for the incisal profile of the porcelain veneer (the incisal edge should reach the vermilion border of the lower lip).
REMEMBER
The incisal edge of the designed veneer should end on the border of the wet and dry red zone of the lower lip (ie, vermilion border) while pronouncing “F” or “V” sounds.
Depth of preparation was controlled with the silicone index (Fig 8-4p). The preparation included extensive restorations on the proximal surfaces, thanks to which the future border between the veneer and composite filling was shifted to the palatal surface (easier to control, as the composite restorations can be replaced in the future if needed, without damaging the veneer). After the preparation was completed, a second retraction cord (so-called deflection cord) – soaked in a hemostatic agent – was placed (Fig 8-4q), and impressions were taken after 5 to 10 minutes. Feldspathic porcelain veneers were fabricated in a dental laboratory (Fig 8-4r).
Fig 8-4p
Controlling preparation depth with a silicone index.
Fig 8-4q
After the preparation was completed, a second retraction cord soaked in a hemostatic agent was placed, and impressions were taken after 5 to 10 minutes.
Fig 8-4r
Feldspathic porcelain veneers.
Their seating and marginal fit were checked on their original stone die and in the patient’s mouth at the next appointment. Next, the proximal relationships and then color, shape, and esthetics in relation to the upper and lower lip were assessed. After approval by the dentist and the patient, rubber dam isolation was carried out, and the tooth surface was conditioned for adhesive cementation (Figs 8-4s and 8-4t). The veneers were cemented with a light-cured composite resin. After removing the composite resin excess, the preparation margin was covered with glycerin gel and finally polymerized (Fig 8-4u). After cementing two porcelain veneers on the maxillary central incisors, the rubber dam isolation was changed to adjacent teeth, and further veneers were cemented on the lateral incisors (Fig 8-4v). The final appearance immediately after cementing veneers and a few weeks later are shown in Figs 8-4w to 8-4bb.
Figs 8-4s and 8-4t
After the dentist and patient accepted the color, shape, and esthetics of the veneers, the teeth were isolated with a rubber dam, and the tooth surface was conditioned for adhesive cementation.
Fig 8-4u
Veneers were cemented, and after removing the composite resin excess, the margins were then covered with glycerin gel and finally cured.
Fig 8-4v
Veneers cemented in pairs in rubber dam isolation.
Fig 8-4w
Clinical situation a few weeks after veneer cementation on teeth 12–22.
Fig 8-4x
The clinical situation with cemented veneers – palatal view.
Fig 8-4y
Close-up of the beautiful surface of the veneers.
Fig 8-4z
Patient’s smile with new porcelain veneers.
Figs 8-4aa and 8-4bb
The situations (aa) before and (bb) after four veneers cementation on teeth 12–22.
VENEERS AND OCCLUSAL PROBLEMS
If we plan esthetic treatment with veneers, and the medical history and oral cavity examination raise doubts about the occlusion, it is worth carrying out a functional analysis.
In many dental practices, in the world of advanced dental diagnostics, deprogramming of the stomatognathic system will dispel all doubts. The most well-proven deprogramming technique requires 4-week use of a special device introduced into clinical practice by Dr. John Kois.14–16
With the deprogrammer, we can:
“Reset” (deprogram) the muscle memory of the temporomandibular joints
Diagnose the direction in which the mandible will move after deprogramming and thus confirm the suspicion of a constricted envelope of function or occlusal dysfunction
Simplify the registration of the centric relation necessary for further treatment planning, including changes in the occlusion (alteration of the vertical dimension)
Pre-indicate a new proposed occlusal vertical dimension by reducing or adding a platform to the deprogrammer
Equilibrate, if necessary, as the deprogrammer can be used as an instrument that controls equilibration (the dentist gradually reduces the platform until premature contacts are identified, which can be gradually eliminated)17,18
KOIS DEPROGRAMMER (KD)
Suppose the loading test and the immobilization test are negative (which initially excludes structural problems and indicates muscular problems of the temporomandibular joint). In that case, a KD may be offered to the patient.19
To fabricate a conventional KD, impressions should be taken with an alginate impression material (Fig 8-5a). The casts should be poured in the next few hours in the dental office or laboratory (Fig 8-5b). The casts should be trimmed using a model trimmer (Fig 8-5c) and then mounted in the articulator in the position of maximum intercuspation (Fig 8-5d).
Fig 8-5a
Alginate impressions of the mandibular and maxillary dental arches for the Kois Deprogrammer.
Fig 8-5b
Alginate impressions should be poured within a few hours so they do not deform.
Fig 8-5c
After pouring, dental casts are trimmed in the model trimmer.
Fig 8-5d
Casts mounted in the articulator.
Next, the dental technician fabricates a labial bow to extend from the most distal tooth on each side of the arch (Fig 8-5e). Then open (horseshoe) palatal coverage with acrylic is made (Fig 8-5f), and an anterior platform is shaped opposing the mandibular central incisors (Fig 8-5g).
Fig 8-5e
Fabricating the labial bow.
Fig 8-5f
Applying the acrylic resin to form a deprogrammer with an anterior platform.
Fig 8-5g
Shaping the deprogrammer’s platform after final polymerization in a high-pressure polymerization device.
The deprogrammer should be polymerized in a high-pressure polymerization device, and the final shaping of the platform and polishing of the deprogrammer takes place after the ultimate polymerization. The platform should slightly disclude all remaining teeth by approximately 1–1.5 mm. The platform should be wide enough in the anterior-posterior dimension, so the patient cannot bite beyond it (Fig 8-5h).
Fig 8-5h
Polished deprogrammer ready to be adjusted in the oral cavity.
It should also be flat (parallel to the horizontal plane) to allow protrusive and retrusive mandibular movement during muscle deprogramming.17,18
REMEMBER
The term deprogramming is defined as actions aimed at changing a specific way of working the muscles, ie, erasing muscle memory using various methods …
PROCEDURES WHEN DELIVERING THE DEPROGRAMMER
(according to Kois Center, Seattle)18,19
1. Confirm that the anterior platform is not wider than 3 mm (Figs 8-5i and 8-5j)
Figs 8-5i and 8-5j
(i) Platform shaped in the dental laboratory is wide enough and should be
(j) Narrowed individually by the dentist to 3–5 mm.
2. The deprogrammer should be inserted passively to avoid any obstacles (Fig 8-5k)
Fig 8-5k
Deprogrammer should be inserted passively and stay in place by accurate fit of the KD plate to the palatal surface of the teeth.
3. Appropriate stabilization is achieved by accurate fitting of the palatal plate and labial bow
4. When the patient has a gag reflex, reduce the palatal plate
5. In the case of a very thick palatal plate, make it thinner, so it does not block the tongue
6. Ask the patient to slide the mandible forward and backward on the appliance (marking with the articulation paper) (Fig 8-5l) and relieve any acrylic thickness, which is palatal to the most retrusive contact on the platform (relieving 3 mm from the most retrusive position) (Fig 8-5m)
Fig 8-5l
With articulating paper, mark protrusive and retrusive mandibular movements on the deprogrammer’s platform.
Fig 8-5m
Excess of the KD platform should be relieved in the palatal part.
7. Reduce the anterior platform to achieve 1–1.5 mm disclusion in the molar region (Figs 8-5n to 8-5p)
Figs 8-5n to 8-5p
(n) Intraoral photograph of the adjusted deprogrammer; (o, p) disclusion of the posterior teeth due to appropriate shape of the deprogrammer’s platform.
8. Reduce the width of the anterior platform until the patient makes one contact point on the platform (Fig 8-5q)
Figs 8-5q and 8-5r
(q) Final reduction of the deprogrammer’s platform and (r) final polishing (laboratory work: DT Iwona Domagała).
9. Final polishing (Fig 8-5r)
10. When delivering the splint, make sure that there is one contact point (Fig 8-5s) on the platform and disclusion between posterior teeth
Fig 8-5s
One contact point will guarantee proper disclusion and muscle deprogramming.
11. Patient receives the Kois Deprogrammer for 4 weeks, with a recommendation to use at night and as much as possible during the day to maximize the effect of muscle deprogramming (Fig 8-5t)
Fig 8-5t
After using the deprogrammer for 4 weeks, confirm that the patient has been correctly deprogrammed – it is achieved when the patient spontaneously adducts the mandible into one certain point of the platform marked with a thin red articulating paper (Parkell 21 µm).
DIAGNOSTICS AFTER DEPROGRAMMING – CENTRIC RELATION (CR) REGISTRATION
Confirmation that the patient has been deprogrammed after 4 weeks of using the KD is achieved when the initial point of contact marked with articulating paper is single, repeatable, and achieved spontaneously upon closing the patient’s mouth, not with any manipulation of the mandible. Using KD, the CR registration can be executed by confirming one reproducible contact point of the anterior platform and simultaneous bite registration with a hard VPS-based material. For this purpose, self-curing acrylic resin (for example, Pattern Resin, GC) is placed on the deprogrammer’s platform. The patient is then asked to close the mandible several times and make sure that they are always biting in the same place (previously premarked with articulating paper). Then, the patient remains in the position that was established on the platform, and the dentist injects the VPS-based material into the space between the posteriors. In this way, the dental technician will receive a bite record of the anterior teeth and a bilateral record of the posterior teeth. Thanks to appropriate registration with the Kois Deprogrammer (Fig 8-6), it is possible to analyze the casts mounted in the articulator in the CR position, confirm the case diagnosis (constricted envelope of function vs. occlusal dysfunction; Fig 8-7) or study the models in different scenarios when changing vertical dimension of occlusion (VDO).20–22
Fig 8-6a
Pattern Resin LS (GC Europe): powder and liquid are gently mixed and transferred with a brush …
Fig 8-6b
… on the deprogrammer’s platform.
Fig 8-6c
Next, the patient closes their mouth several times, biting on the platform so that the dentist is sure that the position marked on the platform (centric occlusion, CO) is consistent with the CR obtained after the patient’s deprogramming.
Fig 8-6d
After the material is set on the platform, the dentist places the mixing tip between the posterior teeth …
Fig 8-6e
… and injects the silicone mass for occlusal registration on both sides, which will record the relationship between the maxillary and mandibular teeth.
Fig 8-6f
After the impression material is set, we receive three places of registration: in the posterior segment on the left and right sides and on the deprogrammer’s platform. Based on this, the dental technician mounts the casts in the articulator.
Fig 8-7
Envelope of mandibular functional movements, the Posselt envelope or envelope of function:
• Left: an envelope with an acceptable function
• Center: widened envelope of function, typical for occlusal dysfunction, often causing a horizontal wear pattern
• Right: constricted envelope of function, often causing a vertical wear pattern
WHY CENTRIC RELATION?
The centric relation (CR) is the mandibular jaw position, in which the condylar processes are situated in the most orthopedically stable position in the fossa of the temporomandibular joints (Fig 8-8).23,24
Fig 8-8
In centric relation (CR), the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior-superior position against the slopes of the articular eminences.
In CR, the condyles articulate with the thinnest avascular portion of their respective discs with the complex in the anterior-superior position against the slopes of the articular eminences. In the past, this position was mainly used when performing complete dentures as a reference point for the relationship between the mandible and the maxilla. Over time, the concept of CR was transferred to fixed prosthodontics, and the validity of this procedure was confirmed using repeatability and studies of muscle function analysis.25–28
The starting point for planning comprehensive restorative treatment is to determine a repeatable position of the mandible in relation to the maxilla. There are two positions of the mandible that can meet this condition:
A. Position of maximum intercuspation (habitual position)
This position may be used when dealing with restorative/prosthetic treatment that does not change the occlusal conditions.
B. Centric relation (reference position)
We need this position in restorative treatment as the position “0” for treatment planning (diagnostic wax-up) and for comprehensive restorative treatment. The ultimate goal in restorative therapy is to achieve maximum intercuspation (MIP) in the CR.
CONSTRICTED CHEWING PATTERN (CCP)
If, after deprogramming, the initial contact is located on the anterior teeth, we can diagnose constricted envelope of function (contact points are checked in position at 45 degrees). The 8 µm articulation foil or Shimstock is held between the anterior teeth (or fremitus can be detected). Orthodontic treatment or alteration of the vertical dimension should be considered to relieve the anterior teeth and reduce the risk of failure of future restorations.29–30 To evaluate and select the appropriate therapy:
Analyze the casts mounted in CR in the articulator.
If you are considering alteration of VDO, you can do a test drive with the diagnostic wax-up (assess whether occlusal rehabilitation by means of restorative dentistry will meet the expected goals).
In the case of a constricted envelope of function, orthodontic treatment should always be considered after appropriate cephalometric analysis. When performing the analysis, the cephalometric reference values should be taken into account and moving the teeth toward the norms should be prioritized when planning the treatment (Table 8-1)31:
Table 8-1 Cephalometric reference values
SNA | 82˚ ± 3˚ | Horizontal position of the maxilla relative to cranial base |
Slope of the maxillary central incisor (U1) relative to the SN | 103˚ ± 6˚ | Inclination of the maxillary central incisors relative to the anterior cranial base |
SNB | 79˚ ± 3˚ | Horizontal position of the mandible relative to the cranial base using B point as a cephalometric landmark |
Slope of the mandibular central incisor (L1) relative to the MP | 90˚ ± 5˚ | Axial inclination of the mandibular incisors and the inferior border of the mandible |
SN–MP | 32˚ ± 5˚ | It determines the type of growth we are dealing with: vertical (> 32˚), horizontal (< 32˚) |
ANB | 3˚ ± 2˚ | Occlusal skeleton class: > 5˚ Class II, <1˚ Class III |
Maxillary anterior facial height (N – ANS) in relation to the mandibular anterior facial height (ANS – Me) | 0.8 | Defines facial height (< 0.8 defines an elongated anterior mandibular part of the face); an important esthetic parameter when planning to increase the vertical dimension of occlusion |
Interincisal angle | 135˚± 11˚ | > 135˚ indicates the possibility of constricted envelope of function (risk of tooth wear and overloading of the anterior teeth) |
REMEMBER
Do not plan comprehensive restorative treatment without CR registration. This position should always be considered as a starting point for prosthetic or orthodontic treatment.
Fig 8-9a
SNA angle (Sella – Nasion – point A) 82º ± 3º.
Fig 8-9b
U1 relative to MV: 103º ± 6º.
Fig 8-9c
SNB angle (Sella – Nasion – point B): 72º ± 3º.
Fig 8-9d
L1 to MP: 90º ± 5º.
Case 5: Constricted envelope of function
A patient presented to the office seeking dental treatment and improved teeth function (Figs 8-10a to 8-10g). While collecting medical history, the following information about functional complaints was obtained:
Figs 8-10a and 8-10b
(a) Patient’s lips in repose allow us to determine the display of the position of the anterior maxillary teeth in relation to the upper lip. If the teeth do not expose from under the upper lip, when planning esthetic treatment, the length of the maxillary front teeth should be increased.
(b) Intraoral photograph: teeth in the maximum intercuspation.
Figs 8-10c and 8-10d
Intraoral photographs of (c) maxillary and (d) mandibular arches.
Figs 8-10e and 8-10f
Posterior intraoral photographs in the maximum intercuspation.
Fig 8-10g
Panoramic radiograph during the patient’s first appointment.
In the left temporomandibular joint, gentle popping without pain during mandible opening
In the past five years, the patient had noticed that his anterior teeth had started to wear down considerably
The patient noted in the information card that he tends to clench his teeth during the day, which was related to the intensity of his work
The clinical examination revealed many restorations with poor marginal adaptation, several carious cavities, extensive tooth wear – especially in the anterior segment of the maxilla and mandible, and erosion cavities on worn surfaces, partially filled with composite by the previous dentist. Examination of the gingival sulcus depth revealed a third-grade furcation defect in tooth 46. In the initial phase of treatment, the focus was on scaling and root planing, treatment of the cavities and replacement of some restorations (Figs 8-10h to 8-10j). Tooth 46 was planned for extraction, which the patient wanted to avoid at all costs.
Figs 8-10h to 8-10j
Intraoral photographs after the initial phase of treatment, including scaling and root planing, replacement of failing restorations, and caries treatment.
Step 1: Esthetic treatment planning
Although the patient did not wish to improve the esthetics of the teeth, it was explained to him that when thinking about changing the function, the treatment planning should start with the anterior teeth.
At this stage Digital Smile Design, DSD was created (Fig 8-10k), followed by making a wax-up of the anterior maxillary teeth (Fig 8-10l). The patient was also asked to bring his historical photograph, in which the maxillary teeth are visible. This evaluation aimed to understand how the smile changed and how much the maxillary teeth were displayed in the past (Fig 8-10o).
Fig 8-10k
DSD presents an esthetic treatment plan proposition before creating the diagnostic wax-up.
Fig 8-10l
Diagnostic wax-up of the maxillary front teeth made on the basis of DSD.
Fig 8-10m
Silicone index was taken from the diagnostic wax-up.
Fig 8-10n
Bis-acrylic composite material (Protemp) is applied to the silicone index to obtain a mock-up.
Fig 8-10o
The patient provided a historical photograph to make it easier to plan the future esthetics and visualize how the tooth wear would progress.
Impressions were taken, the facebow was registered, and, together with photographs, these were all sent to the dental laboratory to be used by the technician during waxing-up. Based on the wax-up, a silicone index was made (Fig 8-10m), followed by a mock-up (Fig 8-10n). Next, the patient was presented with pictures of the expected esthetic plan (Figs 8-10p and 8-10q). The patient and the photographs consultation team accepted the mock-up and, thus, it was possible to proceed to step 2.
Figs 8-10p and 8-10q
(p) Photograph of the current condition of the patient’s teeth and (q) photograph after mock-up.
As the loading and immobilization test revealed negative, the patient was provided with a Kois Deprogrammer, which he had worn for 4 weeks, day and night. The appointment after 4 weeks confirmed the diagnosis of a constricted chewing pattern (CCP) because the first contacts without a deprogrammer were found on the anterior teeth. After 4 weeks, the CR was registered, and the bite records were transferred to the dental laboratory, thanks to which the casts were mounted in the articulator in a CR (Fig 8-10r).
Fig 8-10r
Casts are mounted in centric relation in the articulator.
Orthodontic treatment to improve incisor inclination was discussed, but the patient expected restorative treatment without orthodontics. For this purpose, functional wax-up of the mandibular arch was obtained to eliminate anterior overload (Fig 8-10s).
Fig 8-10s
Functional wax-up of the mandibular arch was obtained in order to eliminate anterior overload.
Step 3: Functional wax-up
It was analyzed how much the VDO should be increased to avoid occlusal overloading of the newly designed anterior teeth. In this case, increasing VDO with the mandibular arch was obtained. It was decided to increase the vertical dimension of occlusion by waxing-up only the mandibular arch. With the wax-up of the mandibular arch, it was possible to study the visualization of the treatment plan.
Step 4: Restorative treatment
A. Mandibular arch
The patient and the dental team executing the treatment plan wanted the most conservative treatment approach and to minimize or eliminate teeth preparation. To restore the new occlusal surface of the mandibular arch, a transparent silicone index was fabricated (Fig 8-10t), made from the diagnostic wax-up. The index was taken in an impression tray. Then, after removing the silicone part, the index was cut (Fig 8-10u) tooth by tooth to make it possible to place each piece in a stable position on the teeth after isolating them with the rubber dam. The cut was made on the cast in such a way as to enable the removal of excess and to avoid loss of stability when being placed on the teeth. Next, the teeth were isolated with a rubber dam (Fig 8-10v), the tooth surface and the restorations were gently roughened with a diamond bur and air abrasion (Air Abrasion Cavity Prep Unit, Danville) (Fig 8-10w). The occlusal, buccal, and lingual surfaces were etched, and after rinsing with a water spray and dried, the bonding system was applied and cured. Each tooth during the restoration process was isolated from the adjacent teeth with metal strips.
Fig 8-10t
Transparent silicone index made based on functional wax-up.
Fig 8-10u
Silicone index was cut tooth by tooth with a surgical blade in order to make direct restorations based on functional wax-up.
Fig 8-10v
Teeth isolation in the third quadrant with a rubber dam.
Fig 8-10w
Slight roughening of the tooth surface with a diamond bur and air abrasion will increase the adhesion to the formerly polymerized composite and untouched tooth surface.
Steps of composite application:
The dentin layer was applied directly on the occlusal surface (Fig 8-11a), then the index was placed on the tooth so the dentin layer would not exceed the planned restoration volume (Fig 8-11b) and light-cured first through the index and then directly after index removal (Fig 8-11c).
Fig 8-11a
Application of the first layer – dentin composite (Enamel Plus HRi, UD3).
Fig 8-11b
Placing the silicone index before polymerization.
Fig 8-11c
Clinical situation after polymerizing the first dentin layer on tooth 37.
The enamel layer was applied directly to the inner surface of the index and then placed again on the occlusal surface, excess material from the buccal and lingual surface was removed, pre-polymerization was done through the index, and the final polymerization was carried out without silicone index (Fig 8-11d).
Fig 8-11d
Clinical situation after polymerizing the enamel layer on tooth 37 (Enamel Plus HRi Bio Function BF2, Micerium).
After restoring molars and premolars (Fig 8-11e) in the third and fourth quadrants, an initial equilibration was performed (Fig 8-11f) to balance the achieved bilateral posterior occlusal stability. Next, the restoration of the anterior teeth was performed. For this purpose, the index made from hard laboratory silicone was adjusted in order to restore the lingual surfaces and the incisal edges. The anterior teeth were isolated with a rubber dam (Fig 8-11g), and a slight chamfer and a long bevel were created on the labial surface. The enamel and the dentin were sandblasted and etched (Fig 8-11h) and thoroughly rinsed with a water spray (Fig 8-11i) before the bonding system was applied. The lingual surface was restored with the silicone index (Figs 8-11j and 8-11k) using the resin of enamel shade for this purpose. The proximal surfaces were restored and formed with the same material using the VariStrip matrix (Garrison) (Fig 8-11l). Once the tooth frame was created (Fig 8-11m), the dentin mamelons were applied to secure appropriate space for the enamel layer (thickness < 0.5 mm) (Figs 8-11n and 8-11o). After applying the outer enamel layer (Fig 8-11p), final light-curing was performed.
Fig 8-11e
Clinical situation after tooth 35 direct composite restoration with index technique.
Fig 8-11f
Initial occlusal equilibration to balance out the contacts between the left and right side after posterior teeth direct reconstruction.
Fig 8-11g
Reconstructing the anterior teeth in the rubber dam isolation.
Fig 8-11h
Etching the anterior teeth.
Fig 8-11i
Situation after rinsing the etchant and before applying the bonding agent.
Fig 8-11j
Lingual walls of all restorations were simultaneously restored using an adjusted silicone index.
Fig 8-11k
Situation after light-curing the composite resin of the lingual surfaces.
Fig 8-11l
Reconstructing proximal surfaces of the mandible anterior teeth with VariStrip (Garrison). The composite resin was applied with a flexible and thin spatula (Applica, LM Arte, Style Italiano).
Fig 8-11m
Situation after reconstructing the tooth frames from the lingual and proximal surface (Enamel Plus HRi Bio Function BF2).
Fig 8-11n
Dentin mamelons (Enamel Plus HRi, UD3) are shaped using the Fissura instrument (LM Arte).
Fig 8-11o
Situation after light-curing of the dentin layer.
Fig 8-11p
Application of the final enamel layer (Enamel Plus HRi Bio Function BF2) with the Applica spatula (LM Arte).
A Profin handpiece was used to create an anatomical shape, and the labial surface was gently corrected (Fig 8-11q).
Fig 8-11q
Creating an anatomical structure with a Profin handpiece.
After removing the rubber dam, the functional corrections of the anterior composite restorations were carried out (equilibration) (Figs 8-11r and 8-11s). All composite areas heavily marked with a 200 µm blue horseshoe articulating paper (after Kois chewing test) were eliminated. At the end of the equilibration, bilateral contacts points were obtained in the posterior segments from the canines to the second molars (Fig 8-11t). At the next appointments, an implant-supported crown was performed on the previously placed implant 46, and a prosthetic crown was replaced on tooth 47 (Figs 8-11u and 8-11v). The situation after reconstructing the entire mandibular arch is shown in Fig 8-11w.
Fig 8-11r
Clinical situation after final reconstruction of the mandibular arch with direct restorations.
Fig 8-11s
Functional shaping of the anatomy of the mandible anterior restorations after the Kois chewing test.
Fig 8-11t
The clinical situation immediately after performing restorations.
Fig 8-11u
Dental implant reconstruction in place of tooth 46 and prosthetic crown on tooth 47.
Fig 8-11v
Clinical situation after placing the composite into the access of the screw-retained crown.
Fig 8-11w
Mandibular arch after restorative treatment.
Increasing the VDO with direct composite restorations in the mandibular posterior teeth creates a space for previously planned esthetic restorations (porcelain veneers) in the maxillary arch (Figs 8-12a to 8-12s). The quintessence of complex treatment planning was wax-up performed at step 1 (Fig 8-10l). Now, the mock-up created of temporary resin was reapplied. After gaining the patient’s approval, the preparation through the mock-up was carried out. The postoperative view is shown in Figs 8-12t to 8-12cc.
Fig 8-12a
Mock-up created on the basis of the diagnostic wax-up: the location of the zenith of the gingival margin was analyzed, and a cauterization procedure was performed to balance out the symmetry of the gingival line.
Fig 8-12b
The clinical situation immediately after electrosurgery of the gingiva on teeth 11, 21, and 23.
Fig 8-12c
Porcelain veneer preparation was started from the mock-up level, reducing the risk of dentin exposure during preparation.
Fig 8-12d
Depth grooves performed on mock-up.
Fig 8-12e
After performing the depth grooves and marking them with a pencil, the mock-up was removed with a curette.
Fig 8-12f
Clinical situation after removing the mock-up: visible, marked depth grooves only on teeth 22 and 13, there is no trace of preparation on the other teeth.
Fig 8-12g
The next step is making the preparation margin, which will be visible for the dental technician and provide a “stopping point” while cementing veneers.
Fig 8-12h
Final minimally invasive veneer preparation.
Fig 8-12i
Control of the teeth preparation in maximum intercuspation.
Fig 8-12j
As the mandible teeth have been restored with composite, it is possible to correct them. Hence, the porcelain veneers have enough space, and there is no need to reduce other tissues of the maxillary teeth. Therefore, the reconstruction of the mandibular arch with composite is practical and easy to correct (the photograph shows the area marked with the pencil that needs to be reduced).
Fig 8-12k
Clinical situation after adjusting the mandibular teeth.
Fig 8-12l
Feldspathic porcelain veneers (IPS InLine, Ivoclar), ready for adhesive preparation and cementation in the oral cavity (laboratory work: DT Artur Nyga).
Fig 8-12m
Rubber dam isolation of two central incisors; under local anesthesia, the tooth structure was sandblasted and then etched with orthophosphoric acid for 20 seconds.
Fig 8-12n
Clinical situation after thorough rinsing of the phosphoric acid …
Fig 8-12o
… and after applying the adhesive system.
Fig 8-12p
Porcelain veneers were cemented symmetrically in pairs; due to very thin veneers (less than 0.4 mm), Variolink Esthetic LC was used for cementation.
Fig 8-12q
Porcelain veneers on teeth 13–23 immediately after cementing and removing the rubber dam.
Figs 8-12r and 8-12s
Marking the occlusal-articulation contacts according to the Kois chewing test (200 µm horseshoe articulating paper) and adjusting in order to eliminate the risk of possible friction observed between maxillary and mandibular front teeth.
Fig 8-12t
Clinical situation a few weeks after cemetation of porcelain veneers on teeth 13–23.
Fig 8-12u
Clinical situation 12 months after restoration. The mandibular arch shows minor chipping of the composite resin in tooth 32, which is considered as an adaptation of the current envelope of function. Chipping of the composite restoration can always be easily restored or polished.
Fig 8-12v
Maxillary arch after reconstruction with porcelain veneers.
Figs 8-12w and 8-12x
Maxillary and mandibular arches in the maximum intercuspation – view (w) from the right and (x) from the left side.
Fig 8-12y
Pantomographic radiograph after complex treatment (teeth 12 and 24 after root canal retreatment; implant in place of tooth 46).
Figs 8-12z to 8-12bb
Photographs of the patient’s smile from (z, aa) semi-profile and (bb) en face after treatment.
Fig 8-12cc
Photograph of the patient’s face with a new smile after treatment.
FROM THE LITERATURE REVIEW
Increasing the VDO is a biocompatible treatment (it reduces the amount of tissue preparation). In addition, it improves dental and facial esthetics and the proportions of the vertical dimension of the face, and is also a part of the TMJ treatment.22
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