An interdisciplinary approach for reconstruction of worn dentition.

Complete tooth wear dentition is multifactorial and has challenges with diagnosis and etiology. Their rehabilitation often requires orthognathic surgery, orthodontics, periodontal surgery, and prosthodontic guidelines for occlusion with harmonious facial and dental esthetics. A patient needs a multidisciplinary approach with systematic analysis to formulate evidence-based approach to improve function and esthetics. Contemporary periodontal therapy also encompasses esthetic treatment where needs are frequently associated with changes in tooth size, shape, proportion, and balance that can adversely affect smile appearance. The article provides an evidence-based guideline for reconstruction of a worn dentition. The completed work includes crown lengthening, provisionalization, socket shield technique, oral implants, and gain in lost vertical dimension with occlusion correction and minimally invasive prosthetic restorations. Copyright:

INTRODUCTION

The reconstruction of a severely worn dentition is often complex and challenging warranting a multidisciplinary approach requiring an esthetic and functional occlusion for a long-term survival. Dental professionals should diagnose early signs that may cause irreversible damage to teeth and institute timely prevention and treatment. A careful examination with in-depth case history (medical, dental, and diet), good photographs, and study casts are important for proper diagnosis. In esthetic dentistry, where the development of proper tooth size, form, and color of restorations are critical to clinical success, often the periodontal component is considerable and must be addressed for a predictable esthetic outcome. One specific area of concern is short teeth where the lack of tooth display and excessive gingival display require clinical crown lengthening.[1] Therefore, crown-lengthening procedures also become an integral component of the esthetic armamentarium with an aim to enhance the appearance and retention of restorations placed within the esthetic zone. The alteration of vertical dimension of occlusion requires space for restoration of teeth, esthetics, and harmonious occlusal relationships as they are a prerequisite for correction of the worn dentition, which may also affect the temporomandibular joint (TMJ), bite force, muscle comfort, and occlusal stability.

In our report, we describe a complex case with wear patterns and its complete reconstruction and rehabilitation with evidence-based guidelines, emphasizing the role of contemporary periodontal therapy in esthetic dentistry.

CASE REPORT

A 54-year-old man reported to our dental clinic for chipping of anterior teeth. There was no relevant medical history. The dental history was frequent visits for caries, impaction of third molars, extractions, and root canal treatment in upper and lower posterior quadrants. On radiographic examination, especially with orthopantomogram and three-dimensional views, the loss of posterior teeth morphology in the upper arch was quite evident [Figures 1 and 2]. There were three metal crowns on the mandibular molars, adding to the structural wear on the antagonist's teeth. The upper right second premolar was grossly decayed along with a missing right second molar. Wear facets were present on complete dentition and the upper incisors had chipped off to half their crown length. On periodontal evaluation, no periodontal pockets were present in any quadrants. There was adequate attached gingiva around all teeth present. The gingival zenith was disturbed in the esthetic zone of both upper and lower arches because of supra-eruption of teeth. Establishing a correct diagnosis and corrective treatment plan suiting the patient's request and overall desires was therefore essential. We obtained the patient's consent for the treatment plan and for the academic use of clinical photographs.

Figure 1

Preoperative three-dimensional view of maxilla showing posterior teeth lost morphology

Figure 2

Preoperative three-dimensional view of mandible showing crowns and partially edentulous ridge

The health of the soft tissues can affect the color, shape, and gingival architecture affecting the dentogingival appearance. A regular gingival margin outline, zenith with ideal symmetry, parallelism, and interdental papilla shape can contribute strongly toward enhancing the esthetics. After evaluating the TMJ for joint sounds and instability, we noted that there were no tension and tenderness with normal mouth opening. The patient had a worn anterior dentition with loss of clinical crown height and had developed an edge-to-edge incisal relationship. The esthetic appearance was lost with no anterior guidance [Figure 3]. For better esthetic effect and an anterior guidance, a raise in occlusal vertical dimension was needed. This would correct the anterior overjet and overbite relationship. It has been stated that in TMJ disease-free patients, fixed appliances should be used instead of removable appliances for raising the vertical dimension. According to Dahl et al.,[2] the raise was achieved by covering the upper six anterior teeth only. Occlusal stability was achieved by intrusion of occluding segments of the arch and extrusion of nonoccluding segments of the arch. This coverage would lead to dentoalveolar adjustment. In our patient, the loss of posterior teeth morphology in both the arches led to damage of anterior tooth wear and their supra eruption [Figure 4].

Figure 3

Incisal exposure at rest

Figure 4

Intraoral clinical views of worn dentition

The fixed metallic Dahl appliance on the six upper anterior teeth intruded lower antagonistic teeth and allowed eruption of the posterior molars bilaterally within a period of 4 to 6 months. The appliance was removed as the bilateral posterior teeth came into occlusion. The impressions of both arches and facebow transfer were then taken.

In the next step, the incisal edge length was analyzed with composite mock-ups of upper incisors and their alignment with convexity of the lower lip [Figure 5]. This increase in size of two upper central incisors was measured and transferred to the laboratory with instruction for complete wax up on all the teeth in the upper jaw, keeping the upper incisors’ length as a reference for the posterior occlusal plane. Accordingly, the lower dentition was built with a raised vertical dimension [Figure 6]. As the incisal edge position was determined, the ideal width to length ratio of all upper incisors and canine could be ascertained. As the central incisor was lengthened by 3 mm, the vertical dimension opened 1 mm posteriorly. The diagnostic wax-up established patient occlusion along with all the anterior teeth. This makeover was copied in the form of a template and marked intraorally for surgical crown lengthening [Figure 7].

Figure 5

Composite mock up

Figure 6

Wax-up with centric relation and raise in vertical dimension of occlusion

Figure 7

Intra-oral markings according to esthetic wax-up for crown lengthening

It is important to have a correct incisal edge position and tooth size before initiating the periodontal procedure. The “Proportion Gauge” (Chu's Aesthetic Gauges, HuFriedy Inc, Chicago, IL) enables objective mathematical appraisal of tooth size ranges in a visual format.[3] Dentists can apply esthetic values and measurement directly in the patient's mouth for the proposed treatment planning. It is a single handle, double-ended instrument with T-Bar and Inline-Tips screwed on the handle. The T-Bar has a rest position on the incisal edge (incisal stop) as the instrument is seated. The clinician can accurately evaluate its length (vertical arm) and width (horizontal arm) proportions and in a way define the correct dimensions of the tooth. The central incisor with red width of 8.5 mm (horizontal) is presumably in correct length (vertical) of the red band (11 mm). Similarly, the blue band stood for the lateral incisor and yellow for the canine [Figure 8a-c]. The subsequent intraoral markings were established as guided by the Chu-proportion gauge, followed by an external bevel gingivectomy to achieve the ideal anatomic crown length [Figure 9a-d]. The “Crown Lengthening Gauge” has a Biologic Perioguage “(BLPG) Tip” designed to measure the midfacial length of the anticipated restored clinical crown and the length of the biologic crown simultaneously during surgical crown lengthening. A full-thickness flap was reflected to expose the underlying osseous topography. The “BLPG Tip” of the crown-lengthening gauge was used to measure the proper midfacial clinical and biologic crown length simultaneously as it had a preset midfacial dentogingival measurement of 3 mm. This visualization of both these parameters simultaneously facilitated in determining the exact amount of bone to be resected [Figure 10]. An apically repositioned flap was secured with periosteal vertical interrupted sutures. There was a gain of approximately 3 mm in the clinical height post crown lengthening [Figure 11a and b].

Figure 8

“T Bar” rest on incisal edge with its horizontal and vertical arm defining the correct size of teeth; (a) central incisor (red band); (b) lateral incisor (blue band); (c) canine (yellow band)

Figure 9

Crown-lengthening procedure; (a) external bevel gingivectomy; (b) central incisor (red band); (c) lateral incisor (blue band); (d) canine (yellow band)

Figure 10

Creation of biologic width

Figure 11

(a and b) Comparison between pre and post crown-lengthening procedure showing gain in clinical height

The patient had an upper left side second premolar fractured but the root seemed healthy and intact. A socket shield technique was attempted before implant placement in the socket. The sequential steps of the socket shield technique were performed according to guidelines by Gluckman et al.[4] [Figure 12a-d] Following adequate anesthesia, without lifting a mucoperiosteal flap, the tooth was decoronated till the soft tissues. The root canal was taken as a guide to further section the root vertically in the buccal and palatal direction. An endodontic file was used to orient and measure the length of the root. Further, it was sectioned till the measured length of the existing root with a tapered fissure bur under copious irrigation. Periotomes were used for the palatal part detachment and the ligaments around the bone. Once it was found mobile, it was removed with micro forceps. The buccal portion was never touched. The buccal shield was further thinned to approximately 2 mm thickness with an inside chamfer. A careful curettage of the extraction socket was performed to remove granulation tissue.

Figure 12

Socket shield technique in upper left second premolar; (a) Preoperative DentaScan; (b) Preoperative clinical picture showing root stump of left upper second premolar; (c) Buccal shield; (d) Palatal implant placement

An osteotomy was prepared palatally in the extraction socket with the sequential drills for 3.3 × 11.5 implant (T. A. G. Medical Products Corporation Ltd., Kibbutz Gaaton, Israel). It was placed 3 mm below the soft tissue margin. Another implant was placed in the lower right second molar area after the above-mentioned shield procedure. The complete diagnostic wax-up included full contours of the teeth with proper centric occlusion. A provisional restoration of auto-polymerizing resin was fabricated [Figure 13]. The incisal edge position was evaluated in relation to lip both esthetically and phonetically. Interferences were removed and canine-guided occlusion was established.

Figure 13

Provisional restorations

In case of complex rehabilitations, it is impossible to incorporate all the planned esthetic and functional changes in the first provisional restoration. We, therefore, decided to make a second reinforced provisional restoration using glass fiber for reinforcing the acrylic resin structure. These provisionals were in the mouth for the next 4 months. The final restorations included fabricating crowns on posterior teeth and this was achieved by sectioning the provisionals distal to canines. The anterior provisionals maintained the current vertical dimension of occlusion. Minimally, invasive preparations on the enamel were done on posterior teeth (all molars except lower second right molar which was restored later as it was an implant restoration along with both upper right second premolars). The crowns (IPS E. max Zirconium Oxide Crowns) for both posterior arches were cemented (3M EspeRelyx U 200) [Figure 14]. The occlusion was adjusted in a centric stable position without interferences during protrusion and lateral movements. The veneer preparations in both anterior arches were minimally invasive with maximum preservation of enamel to provide a better esthetic and biological restoration.[5]

Figure 14

IPS E. max Zirconium Oxide Crowns cemented in posteriors and veneer preparations on anteriors

For the bite registration, we used a 0.0005-inch thin occlusal registration strip, which helped to verify that the patient closed in centric occlusion. Twelve, minimally invasive glass-ceramic, veneer restorations of lithium disilicate ceramic, for anterior teeth of both arches, were delivered [Figure 15]. The laminates were carefully cemented on all the prepared tooth surfaces. The implant-supported screw restorations were also placed on the second upper right premolar and the lower right second molar along with the anterior restorations. We gave our patient a mutually protected occlusion [Figure 16]. A protective single arch splint was further given to the patient for use at night for the initial 6 months. The patient was pleased with the new set of teeth. A recall of every 6 months was kept for the patient to regularly visit the clinic for oral hygiene maintenance and radiographic evaluation [Figure 17]. Radiographic evaluation was repeated after 2 years [Figure 18].

Figure 15

Glass-ceramic maxillary and mandibular veneers (Lithium disilicate ceramic)

Figure 16

Final prosthesis

Figure 17

Postoperative orthopantomogram after 6 months

Figure 18

Postoperative orthopantomogram after 2 years

DISCUSSION

Dental wear is a process of loss of tooth-hard substance. Attrition, abrasion, and erosion are basic mechanisms of tooth wear, but coarse diet, gastric disorders, and opposing restorative material may also become etiologies for the disease. It is very difficult to diagnose a worn dentition as it can originate from a combination of causes. Careful diagnosis with thorough medical and dental history, diet, habits, and proper clinical examination is essential. Medical problems such as gastroesophageal disorders, obstructive sleep apnea, alcoholism, and eating disorders can also contribute to the etiology.

Identification of all parameters is a prerequisite for treatment planning. In a case report by Wong and Botelho, advanced erosive tooth wear in a patient was managed with a negative overjet by Dahl appliance to improve the anterior incisal relations both from a functional and esthetic point of view providing a satisfactory 5-year result.[6] Current evidence suggests that occlusal wear does not lead to loss of vertical dimension as there is a continuous eruption of teeth and it is well compensated.[7]

The synergy that exists between periodontics and restorative dentistry is quite dynamic and inseparable. The demand to establish the correct tooth size and proportion drives the periodontal component of esthetic restorative dentistry. We evaluated patient incisal edge position with patient's lip at repose and then at altered occlusal vertical dimension. This further needed periodontal esthetic surgery for alterations of the gingival zenith of upper anterior teeth. Visual precision without guessing or emotional estimation is vital for successful, predictable, cost-efficient treatment, which prompted us to employ Chu's proportion gauge for accurate position of osseous topography during crown lengthening.[3] Several clinical reports have described periodontic and restorative management of patients with generalized wear of dentition.[8910]

Minimally invasive treatment has been well accepted lately for worn dentition due to advances in restorative materials and adhesive bonding.[711] The veneer restorations were part of the full mouth rehabilitation; this preparation was chosen to fill the space between palatal aspect of maxillary incisors and the incisal edges of mandibular incisors. Adequate canine guidance was given along with “freedom in posterior centric” concept to avoid load on posterior restorations.[12] The patient is being followed up and is on a 6-month recall for the last 2 years.

CONCLUSION

A new occlusion for a denigrating worn dentition is a challenging task and requires a multidisciplinary approach for long-term success. Our report describes a practical sequence for esthetically restoring a worn dentition while fulfilling the evidence-based occlusal guidelines. The treatment planning in such cases should follow an ordered approach to account for tooth wear, overall esthetics, and occlusion by establishing proper tooth size, form, and color of restorations.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.