Restoring the Worn Anterior Dentition for Function and ...

82 TheJournalofCosmeticDentistry•Summer2007 Volume23•Number2

AbstrAct

Providing a durable restoration of the worn dentition to maintain or improve function and esthetics is a satisfying achievement for well-trained dentists and a necessary service for their patients. The case presented here demonstrates the use of conservative indirect feldspathic veneers to augment worn anterior teeth. Diagnosis, treatment planning, and clinical techniques are addressed.

An entire specialty is evolving that addresses the beauty of natural healthy dentitions.

IntroductIon And chIef complAInt

Bonded direct and indirect dental restorative materials permit the predict-able and esthetic restoration of worn dentitions. Patients who are increasing-ly health-conscious and who desire a more youthful appearance and attrac-tive smiles seek these services. An entire specialty is evolving that addresses the beauty of natural healthy dentitions, with particular attention paid to function in a healthy stomatognathic environment. The predictable restora-tion of such dentitions is possible only with a thorough understanding and application of fundamentals of occlusal theory.1

Restoring the Worn Anterior Dentition for Function and Esthetics

CliniCal SCienCe Kleeberger

Dr. Kleeberger is a general practitioner in full-time practice in Langley, British Columbia, Canada. He received his dental degree from the University of Al-berta in 1978 and is an alumnus of the Millennium Institute in Calgary, Al-berta, Canada; and of PAC~Live pro-grams at University of the Pacific in San Francisco. He mentors study clubs and presents courses in esthetic restorative dentistry, materials, and treatment planning. Dr. Kleeberger is a sustaining member of the AACD and a founding member of both the Canadian Academy of Cosmetic Dentistry and the Canadi-an Academy for Esthetic Dentistry. The case presented here was awarded a Bronze Medal in the AACD Smile Gal-lery at the 2006 Annual Scientific Ses-sion in San Diego, California.

byBruce G. Kleeberger, D.D.S.


The patient, a 42-year-old female, came to our office in September 2005 requesting treatment of her discoloured, misaligned, and worn upper anterior teeth. She believed that her teeth made her look older than she was. Of particular concern was the upper right central incisor tooth, which had been treated end-odontically many years earlier and was now darker than the adjacent teeth.

hIstory And exAmInAtIon

Pre-treatment photographs are shown in Figures 1 through 5. There were no significant findings in the patient’s medical history. Her dental history included restoration of pos-terior teeth with amalgam and com-posite materials, endodontic treat-ment of the maxillary right central incisor and mandibular left first and second molars, third molar extrac-tion, and routine hygiene therapies.

Her periodontal health was with-in normal limits, with normal sul-cular depths and no tooth mobility. Radiographic examination was nor-mal, with normal bony morphol-ogy and missing third molars. There were mature pulps, the previous

endodontic treatment of the upper central incisor was adequate, and pulp tests of all teeth were normal.

The characteristics of wear included the loss of enamel on the inciso-lingual of the maxillary anterior

teeth, and buccal cusp tip wear of the bicuspids.

The occlusal classification was Angle Class I bilaterally with normal overjet and overbite, and there had been no orthodontic intervention. There was no tension or tenderness in the muscles of mastication on pal-pation. Palpation of the tissue later-al to the temporomandibular joint and of the posterior capsule with the intrameatal approach revealed no clicks, pops, ligament laxity, or discomfort. The patient reported no history of symptoms or aware-ness of parafunctional habits such as clenching or nocturnal grinding. Evaluation of the occlusion revealed bilateral group function in lateral excursions involving the incisors, cuspids, and bicuspids, with light balancing contacts on second mo-lars bilaterally.

fIndIngs

The characteristics of wear in-cluded the loss of enamel on the in-ciso-lingual of the maxillary anterior teeth, and buccal cusp tip wear of the bicuspids. The incisal edges of the maxillary central incisors were thin and transparent, which is typical of wear on the lingual of these teeth. In this case, when assessing the pattern of wear and possible dental resto-ration, the following findings were considered significant:

•Therewasastablecusp-to-fossarelationship of opposing teeth.

•Wearwasalmostexclusivelylimited to the anterior teeth.

•Therewerebilateralbalancinginterferences on the posterior teeth.

The importance of these wear characteristics is that it suggests it is possible to restore anterior guidance with restoration. The importance of anterior guidance is that it protects posterior teeth from wear.

The esthetic evaluation revealed an overall shade Lumin A3 (Ivoclar Vivadent; Amherst, NY). The width-to-length ratio of the maxillary cen-tral incisors was equivalent, rather


Figure 1: The patient’s chief complaints were wear and discoloration of her teeth. Note the asymmetrical

lip, which tends to hide the smile in this 1:10 magnification view.

Volume23•Number2 Summer2007•TheJournalofCosmeticDentistry 85

than the ideal 80:100. This suggests a possible 20% loss of tooth length due to wear. There was normal gin-gival display on smiling and a sym-metrical incisal plane. The Grid Analysis System proposed by Nay-lor2 was applied to assess the sym-metry, balance, and proportion of the teeth within the patient’s smile and face (Fig 6).

treAtment plAn

After appropriate examination and consultation with the patient, it was decided that teeth ##4–7 and ##9–13 would receive indirect all-ceramic restorations, and #8 would

receive a porcelain-fused-to-metal restoration. Key to the restorations’ longevity was design of the occlu-sion to provide cuspid-protected guidance in lateral excursions, smooth protrusive disclusion on at least two incisor teeth at all times, and absence of balancing contacts during lateral excursions.3

treAtment descrIptIon

WAx-up

Study models were mounted on a SAM 3 semi-adjustable articulator (Great Lakes Orthodontics; Tonawa-

nda, NY), in centric relation using the bilateral manipulation technique described by Dawson.4 Photographs and radiographs were prepared. A thorough occlusal examination and review of the stomatognathic system was conducted.

A full-contour diagnostic wax-up of all involved teeth was per-formed prior to beginning clinical treatment. Smile design principles, including “golden proportion” and facial esthetic analysis, were em-ployed.5 Anterior disclusion in lat-eral and protrusive excursions were important considerations in the


Figure 3: In the 1:2 magnification retracted view, the wear of the cusp tips of the cuspids bilaterally is evident. The bicuspids are constricted bilaterally relative to the cuspids and molars, not filling the

buccal corridors as much as is ideal.

Figure 4: The extent of crowding and misalignment of the maxillary incisors is evident in this 1:2 maxillary

occlusal view. The cusp tips of the bicuspids are beginning to wear.

Figure 5: The mandibular 1:2 magnification occlusal view demonstrates the crowding of the lower incisors

and their labio-incisal wear.

Figure 2: The 1:2 magnification view of the unretracted smile shows the discoloration of the right central incisor. The wear of the central incisors has made them shorter than the lateral incisors, rather than slightly longer, as in the unworn condition.



Figure 6: The Grid Analysis System2 is superimposed over the 1:2 magnification of the pre-treatment full-face view. Facial

anatomical landmarks are used to evaluate the orientation of the incisal plane, long

axis and proportion of the sizes of the anterior teeth, and the midline.

occlusal scheme of the wax-up. Ad-equate inclination of the discluding surfaces of anterior teeth on the wax-up was ensured to provide preven-tion of working side interferences (contact of the restored bicuspids) and balancing interferences. As the patient had worn away the cuspid and bicuspid cusp tips and inclines, she had developed a flatter guidance and broader envelope of function. The wax-up would be the prototype for the provisionalization, which would test the restoration of ante-rior guidance and the patient’s toler-ance of the more restricted envelope of function.

From this important diagnos-tic step, it was determined that minimal adjustments to the occlu-sion of the models were necessary to achieve uniform anterior and posterior contacts in centric rela-

tion without posterior balancing interferences. An omnivac matrix, Sil-Tech putty matrix (Ivoclar Viva-dent), incisal matrix, and custom impression trays were fabricated by James Neuber, R.D.T., of Ocean Ce-ramics Laboratories in Coquitlam, British Columbia.

All mandibular and maxillary an-terior 10 teeth were then bleached using ZOOM (Discus Dental; Culver City, CA) in-office power bleaching as recommended by the manufac-turer (three 20-minute sessions).

prepArAtIon

Three weeks after the bleach-ing, the restorative treatment be-gan. Chromoscop 030 (Ivoclar Vivadent) was selected as the pre-ferred final shade before anesthesia or any tooth-altering procedures were done.

The teeth were anesthetised with 4% articaine with 1:100,000 epi-nephrine. The anterior middle su-perior alveolar (AMSA) protocol (Fig 7) was used. This technique is preferred to achieve sufficient an-esthesia without affecting mobility and normal drape of the maxillary lip. Using the polyvinyl matrix from the wax-up (Fig 8), the information from the wax-up was transferred to the mouth by creating a mock-up on the involved teeth with Integrity Bis-Acryl chemically cured resin (Dent-sply Int.; York, PA).

At this point, the occlusion, with the mock-up on the teeth, was reas-sessed to ensure the accuracy of the wax-up as performed on the models. Again, it was noted that minimal ad-justments would be required to pro-vide uniform posterior contacts in centric relation and smooth anterior


guidance in the absence of balanc-ing contacts. The adjustments were made.6

The lips were retracted with an OptraGate vinyl retractor (Ivoclar Vivadent) and isolation was provid-ed with cotton rolls and paper-dry angles.

All teeth were prepared with coarse and fine Brasseler (Savannah, GA) diamond burs using the ma-trices and the mock-up as guides.5,7

Where possible, interproximalcontacts were not violated. Care was taken to prevent penetration through enamel into the dentine so as to provide a predictable bonding substrate; and preparation was lim-ited to enamel, particularly in mar-ginal areas. Reduction was at least 1.5 mm incisally and .5 mm facially in three planes of space to allow for restorative material thickness. Minor adjustments to the gingival contours of the central incisors were made using a ceramic tissue-trim-ming bur (Axis Dental; Irving, TX). Ultradent (South Jordan, UT) 00 re-traction cord moistened with Visine

(Pfizer; New York, NY) was pressed into the sulci of all teeth. Aquasil Ultra (Dentsply Caulk; Milford, DE) heavy- and extra-light viscosities polyvinyl impression material was used. A facebow transfer and inter-occlusal records were prepared.

The early diagnosis of pathological dental wear and occlusal

parafunction can reduce the complexity of replacing the missing

tooth mass.

provIsIonAl fAbrIcAtIon

Photographs of the preparations, along with the stick-bite5 (Fig 9) and stump shade (Ivoclar Vivadent) were made. The provisionals were fabri-cated directly on the teeth using the “shrink-wrap” technique5 with In-tegrity self-curing resin bleach shade (Figs 10 & 11). This shade approxi-mated the selected Chromoscop 030 shade (Fig 12). Necessary mi-nor adjustments were made to the contours of the provisionals for es-thetics. Occlusion was adjusted to

ensure uniform posterior centric contact, including shim stock thick-ness (.01 mm) of relief anteriorly, cuspid rise in lateral excursion, and protrusive disclusion with simulta-neous contact on at least two inci-sor teeth. The absence of balancing contacts was confirmed. The details of the patient-approved provisionals were recorded in an alginate impres-sion and in photographs. An articu-lated model from this impression, accompanied by the photographs, was provided to the laboratory.

The patient received hygiene in-structions and instruments to enable her to floss around the provisionals, as well as topical chlorhexidine to be applied at each brushing to re-duce gingival inflammation.

After evaluation of the poured and mounted model, it was de-termined that the preparations re-quired further revision. The steps above were repeated.

The laboratory prepared a cus-tom shade map (Fig 13). A porce-lain-fused-to-metal restoration for tooth #8 was fabricated according to


Figure 8: The polyvinyl matrix is used to transfer the information from the wax-up to the mouth.

Figure 7: The landmarks for the AMSA injection are the bicuspids, the maximum curvature of the palate,

and the gingival margin. Anesthetic (1.8 cc) is injected extremely slowly upon contact with bone.


Figure 12: A photograph of the provisionals with the approved shade tab selected in consultation with the patient serves to guide the technician. It also records,

for the patient’s information, the shade chosen relative to the provisionals.

Figure 11: A photograph of the provisionals in the full face, smiling, demonstrates the desired result. The provisionals have received the patient’s approval.

Figure 10: A photograph of the provisionals with the lips smiling demonstrates the desired result to aid

the technician.

Figure 9: The stick-bite, composed of fast-setting polyvinyl, and a disposable brush placed on the

preparations and aligned perpendicularly with the face, allows more information about the desired incisal plane orientation to be transferred to the

laboratory. A photograph of the stick-bite in place on the patient assists the technician in understanding

orientation of the preparations to the face.


the Eubank™ technique developed by Ocean Ceramics (with Duceram Plus [Degussa; Rosbach, Germany] and Tilite [Talladium Inc.; Valencia, CA]). This technique utilizes a ce-ramic labial construction with a lin-gual metal framework (Fig 14). This design provides strength on the lin-gual of full-coverage anterior resto-rations where they are at highest risk of fracture from occlusal stresses.

This principle is well shown by Drs. Magne and Belser.8 Figure 15 shows, in red, the stress-bearing areas as an incisor is loaded in protrusive excursions.

Powder-liquid feldspathic ve-neers (Duceram Plus) were fabri-cated for the remaining teeth. For comparison, the two central incisor restorations are shown in Figures

16 and 17. When the restorationswere returned from the laboratory, they were tried on the model for fit and draw.

evAluAtIon

The patient returned to try in the restorations. Before removal, the provisionals were examined for wear and fracture; neither was found. The patient’s absence of symptoms


and asymptomatic musculature on palpation were noted. This evalu-ation is important to determine if the restoration of anterior guidance with steeper lateral guidance and narrowed envelope of function re-duced any parafunctional activity or produced any musculoskeletal symptoms.

The patient was again anesthe-tized using the AMSA protocol, and the provisionals were removed. The preparations were polished with pumice and chlorhexidine. The ab-sence of hemorrhage from the gin-gival tissue was a result of excellent hygiene and the topical application of chlorhexidine during the provi-sionalization period. The restora-tions were tried in dry on each tooth individually, then in pairs and, final-ly, all together. Then they were again tried in all together with RelyX ve-neer cement try-in paste (3M ESPE; St. Paul, MN), with a darker shade on one side and a lighter shade on the other to evaluate the effect of ce-ment shade on the final result.

A need to correct the low-value appearance of tooth #8 was identi-fied. The area was lightly prepared

again, primed, and bonded (SE Bond, Kuraray Co.; Tokyo, Japan). The dark area was coated with Es-thet-X opaque white resin (Dentsply Caulk). The patient approved the restorations while they were retained on the teeth with try-in paste.

cementAtIon

A rubber dam was placed to iso-late the entire restorative area5 and to prevent moisture contamination during the bonding procedure. The anterior six teeth were etched with phosphoric acid for 10 seconds, fol-lowed by application of the SE Bond primer and bonding agent only on any small areas of exposed dentine, according to the manufacturer’s directions. The six anterior restora-tions were silanated, coated with bonding agent, and loaded with Re-lyX translucent shade cement. They were then seated on the prepared teeth and the cement removed and cured in the “tack-and-wave” meth-od.5 The remaining bicuspid restora-tions were bonded similarly, but in separate steps.

After all restorations were ce-mented, any residual cement was removed with a #12 scalpel blade

and finished using Epitex strips (GC America; Alsip, IL). Margins on concave surfaces (lingual) were finished using football-shaped fine diamond high-speed instruments (Brasseler) with water. Polishing on margins was accomplished using Enhance and PoGo composite fin-ishing points (Dentsply Caulk) and diamond polishing paste.

Adjustments were made to the occlusion to create uniform poste-rior contacts in centric contact with shim stock (.012 mm) relief in the anterior region. Smooth immediate cuspid rise in lateral excursions and uniform protrusive disclusion on at least two teeth at all times were con-firmed (Fig 18). The adjustments were made with fine diamond burs and any affected porcelain polished using Dialite (Brasseler) cups and points. The final restorations are shown in Figures 19 through 21.

Finally, impressions were made to fabricate a maxillary full-coverage splint to ameliorate any persistent parafunctional habits and create a more predictable prognosis for the restorations. Like the final restora-tions, the appliance was adjusted


Figure 13: The technician can prepare a map of the planned ceramic layering and shading for current and future reference.

FLU-Sunny

Dentin AZ

dentIn frAme

Dentin Bleach 2

½ Dentin AI + ½ TC

½ Dentin AI + ½ SI

seAl

T C + 15% Ivory

T C + FLU-Bright

bAke


Figure 14: An occlusal view of the model demonstrates the minimally invasive preparations

achievable with careful technique. The lingual metal framework has been applied to the die before

application of porcelain.

Figure 15: This diagram from Magne and Belser8 demonstrates the location of stress concentrations

as the incisors are dynamically loaded. The lingual concavity is the site of greatest stress

concentration.(From Bonded Porcelain Restorations in the Anterior Dentition: A Biomimetic Approach, p.33, by P. Magne and U. Belser.

Reprinted with permission of Quintessence Publishing Co., Inc.)

for uniform posterior contacts and anterior disclusion, and checked on recall for signs of wear. Recall examinations were performed at two weeks and then at two-month intervals to confirm stability of the restored occlusion.

dIscussIon

The patient’s initial motivation for seeking treatment was her con-cern about the worn appearance of her teeth. Equally or more impor-tant, however, was the diagnosis of wear and its etiology. In this case, the characteristics of wear included the following:

•equallengthofmaxillaryinci-sors

•worncusptipsofcuspids

•earlywearofbicuspidcusptips

•thinandtransparentincisaledg-es of maxillary central incisors, typical of wear on the lingual of these teeth.

The importance of these wear characteristics with respect to occlu-sal function is the loss, at a relatively early age, of anterior guidance.1,5 The progression of wear resulting from parafunctional habits (termed eccen-tric bruxism by Dawson1) in normal occlusions begins with the loss of cuspid protected disclusion as the cupsid incisal tips wear away and

the bicuspid teeth begin to interfere and wear in group function. As bi-cuspids wear and the molars begin to participate in the group function, there can be an increase in muscu-lar intensity and wear resulting from parafunction. Also, occlusal inter-ferences often are discovered in the presence of parafunctional habits.

The early diagnosis of pathologi-cal dental wear and occlusal para-function can reduce the complexity of replacing the missing tooth mass. Thorough consideration of the oc-clusal scheme to be restored, the materials to be used in the restora-tion, and techniques to prevent re-currence of the wear are imperative.



Figure 16: This labial view of the right central incisor porcelain-fused-to-metal restoration and left porcelain bonded restoration demonstrates the excellent detail

of the incisal translucent zone.

Figure 17: This internal view of the restorations in Figure 16 shows the metal on the lingual surface of

the right central crown.

Figure 18: The black marks are the centric occlusal stops and the red marks are the lateral and protrusive

excursions. There is immediate disclusion in excursions and, in protrusive movements, two teeth

are in contact at all times.

Figure 19: As the patient becomes more confident in the appearance of her smile, the asymmetry of the lower lip is less pronounced in this 1:10

magnification view.

Figure 20: The 1:2 magnification view of the unretracted smile shows the correction of the

discoloration of the right central incisor. The teeth have been restored to create ideal incisal contours and

proportionate widths and lengths.

Figure 21: In the 1:2 magnification view, the bicuspids restorations correct the buccal corridor

deficiency.



Eliminating occlusal interfer-ences and providing anterior guid-ance may reduce or eliminate the parafunctional habits.1,3 This can be tested in the individual patient with provisional restorations, trial splint therapy, or even Bite Strips (Great Lakes Orthodontics). The final res-toration may require adjustment to avoid reintroducing interferences, and should be checked on recall to confirm that the occlusion remains stable. Although it is preferable to avoid long-term splint therapy, if continued parafunctional activity is suspected, a protective appliance may be provided.

Through a systematic approach to record taking, diagnosis, treatment planning, application of fundamen-tal concepts of occlusion, treatment delivery, and reassessment of func-tional esthetic results, a predictable long-term restoration of the worn dentition can be achieved.

conclusIon

The predictable restoration of worn teeth is very much an appli-cation of objective, clinically tested techniques. However, it also is a subjective process of understanding the patient’s goals, as well as a step-by-step approach to ensuring each patient’s satisfaction by taking into account individual appreciation of what constitutes optimal esthetics.

Restoring the worn dentition is a functional esthetic augmenta-tive process. An understanding of pathologies of occlusion, materials science, and clinical technique are necessary to provide predictable therapies to our patients.

References1. Dawson PE. Functional Occlusion from TMJ

to Smile Design (chapter 16). St. Louis, MO: Mosby Elsevier; 2007.

2. Naylor CK. Esthetic treatment planning: The grid analysis system. J Esthet Restor Dent 14(2):76-84, 2002.

3. Dawson, op. cit., chapter 29.

4. Ibid., pp. 76-81.

5. Spear F. Occlusion in clinical practice [course]. Seattle Institute for Advanced Dental Edu-cation;Seattle,WA,2003.

6. Dawson, op. cit., chapter 33.

7. Magne P, Belser U. Novel porcelain lami-nate preparation approach driven by a diagnostic mock-up. J Esthet Restor Dent 16(1):7-18, 2004.

8. Magne P, Belser U. Bonded Porcelain Resto-rations, A Biomimetic Approach. Hanover Park, IL: Quintessence Pub.; 2002.

Acknowledgments

The author thanks James Neuber, R.D.T., of Ocean Ceramics in Co-quitlam, BC, Canada, for his attention to detail and dedication to the techni-cal excellence in this case. Very special thanks also are extended to AACD Ac-credited member Dr. Steven Hill, for his support and guidance.

______________________v


The Orange County Academy of Cosmetic Dentistry

Grand Inaugural Meeting

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Speakers

Dr. Larry Addleson, DDS•Fellow & Past Pres., AACD•International Speaker,Adhesive Dentistry

Dr. Nick Davis, DDS•Past President., AACD•Accredited, AACD•International Speaker

Dr. Bruce Crispin, DDS, MS•Accredited, AACD•Founder & Director,Esthetic Professionals

John Haupt, MDT•Founder, President.,Haupt Dental Lab Inc.•Fellow, AACD.

Dr. Jack Ringer, DDS•Accredited, AACD•Faculty,Esthetic Professionals

Dentistry and the Aging Face

Selecting the RightAll Ceramic Restoration

Techniques and Materials for Optimizing Esthetic Resultswith Indirect Restorations

Illusions

The Orange County Academy of Cosmetic Dentistry’s Grand Inaugural Meeting will be a full day of exciting and informative lectures by renowned AACD accredited speakers focusing on accreditation and contemporary esthetic dentistry!!

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