6 Dahl Appliance

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J. Adv Oral Research CASE REPORT

All Rights Res

Modified Dahls Appliance: Aclinical ReportRucha Kashyap* Zubeda Begum

Mohammed Hilal

Hari Prasad

*Post Graduate student,

MDS, Professor,

MDS, Reader, Department of Prosthodontics, M RAmbedkar dental college and hospital, Bangalore, India.

Email:[email protected]

Abstract:

Dahl in 1975 gave a concept describing the

management of tooth surface loss (TSL). Dahlsconcept can be successfully and safely applied to avariety of clinical situations. This clinical reportdescribes the treatment of a partially edentulouspatient with generalized TSL. A simplified form of

Dahls appliance was used to create inter-occlusalspace, to facilitate a cost-effective treatment and meetthe functional and psychological needs of the patient.Thereby the treatment described has simplified themanagement of historically complex problem.Key words: Tooth loss, psychosocial aspects of oralhealth, prosthodontics.

Introduction:

Tooth surface loss in majority of patients, isaccompanied by dento-alveolar compensation[1].Thesephysiological compensatory processes ensure that, for

the majority of patients, occlusal contacts aremaintained in order to maintain the efficacy of themasticatory apparatus.

[1,2] The apparent lack of

interocclusal space presents a dilemma for the dentist.Dahl and his colleagues met the challenge of restoringattrited teeth. In 1975, Dahl, Krogstad and Karlsendescribed the use of a partial bite raising applianceto create inter-occlusal space in an patient with severe

attrition[3]

.The inter-occlusal space was obtained by acombination of intrusion of the anterior teeth in

contact with the appliance and eruption of theseparated posterior teeth

[4]. The Dahl Concept refers

to the relative axial tooth movement that is observed

when alocalized appliance or localized restorationsare placed in supra-occlusion and the occlusion re-

establishes full arch contacts over a period of time.[4,5]

The concept of relative axial tooth movement wasrecognized, and published, prior to Dahls work

of 1975.[2]In 1962, Andersen[6] described the idea ofexperimental malocclusion by placing restorations insupraocclusion. Dahl and Krogstads furtherpublications

[7-9]of an implant-cephalometric study,

using fixed tantalum implants placed in the basal boneof the maxilla and mandible, concluded that theinterocclusal space was created by axial movement of

the teeth rather than a change in their inclination[8,9]

The design and materials used to construct theappliance have changed dramatically since Dahlsoriginal appliance

[10,11]. Many materials can be used to

construct such an appliance as long as the principlesof the technique are adhered to. The aims of a Dahlappliance are as follows.

A thickness of material should be placed onthe incisal/ occlusal aspect of those teeth where thecreation of interocclusal space is necessary. There

should be no mucosal-borne component. Thethickness of this material placed should directly relate

to the amount of inter-occlusal space that is required.This will determine the increase in the verticaldimension of occlusion as measured at that particular

site in the mouth. Stable inter-occlusal contactsshould be provided. The appliance should not impede

the movement of the discluded teeth. The literaturereports that the objectives of the Dahl concept areachieved in the majority of cases (94%-100%)[8-13]and that this space creation occurs irrespective of ageand sex.

The purpose of this clinical report is toillustrate: (1) The use of dahls concept and adhere to

the principles of his technique. (2) The use of aneconomical material for the fabrication of Dahlsappliance. (3) A cost-effective treatment of a partiallyedentulous elderly patient.

Case report:A healthy 45-year-old partially edentulous

woman presented with a dental history whichincluded removal of teeth due to caries and placementof a maxillary fixed partial denture that was removeddue to localized infection (Fig.1). The patient reporteddiscomfort in social settings and an inability topartake in a normal diet. The patient expressed adesire to have a stinting and functional denturefabricated for her maxillary arch.

Serial Listing: Print ISSN (2229-4112)

Online-ISSN (2229-4120)

Formerly Known as Journal of Advanced Dental

Research

Bibliographic Listing : Indian National Medical

Library, Index Copernicus, EBSCO Publishing

Database, Proquest, Open J-Gate.


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Journal of Advanced Oral Research, Vol 3; Issue 1: April2012 www.ispcd.org

A thorough clinical examination was performed and apanoramic radiograph recorded and evaluated.Preliminary examination revealed fractured maxillaryright central incisor, maxillary left canine and firstpremolar. Missing maxillary left second premolar andfirst molar. In addition, she had generalized attritedteeth and diminished interocclusal space. Since therewere both radiographic and intraoral evidence of lackof interocclusal space for fabrication of fixed orremovable prosthesis, also keeping in mind the cost-effective factor, a treatment plan was chosen whichwas in compliance with the patients desire. Afterinitial examination, diagnostic impressions were madewith irreversible hydrocolloid and diagnostic castwere articulated in a semi-adjustable articulator usingwax rim placed on record bases in centric relation.Because of the deficient interocclusal space a fixed

partial denture for maxillary right posterior was notpractical. A maxillary interocclusal appliance was

fabricated using thermoform plate to temporarilyprovide an occlusal condition that allows thetemporomandibular joints to assume the mostorthopedically stable joint position. Patient wasinstructed to wear the appliance only at night for 4

weeks. She was recalled and reviewed weekly.[14]

Theimpression for the definitive appliance was made

using rubber base impression material. Definitive castwas poured and send to the lab for the fabrication ofmaxillary full arch acrylic appliance (Fig 2). Patient

was instructed to wear the appliance 24 hours a dayexcept when eating meal and brushing for 6 months.

The patient responded favorably to the treatment. Anincrease in vertical dimension equal to the thicknessof the appliance was observed as described by dahl inhis original article and abiding by the principles offabrication of dahls appliance.

[3] The increase in

vertical dimension was due to intrusion of the

Fig 1- Partially edentulous patient with missing

maxillary left second premolar and first molar;

fractured maxillary right central incisor, maxillary

left canine and first premolar and generalized

attrition

Fig 2- Modified dahls appliance: maxillary full

arch appliance

Fig3 - Intraoral view of the cast post for maxillary

right lateral incisor and left lateral incisor and

canine

Fig 4 - Crown preparation of maxillary teeth for

metal-ceramic crowns


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Fig5 - Provisional prosthesis after cementation

Fig6- Face bow transfer on the articulator

Fig7- The definitive cast articulated in a

semiadjustable articulator with wax patterns ofthe definitive prosthesis

Fig8- Intra-oral view of the definitive prosthesis

covered teeth by an amount equal to the thickness ofthe appliance.[15]

A surgical crown lengthening procedure formaxillary left lateral incisor and canine wereperformed. After which cast post for maxillary rightlateral incisor and left lateral incisor and canine werefabricated and cemented (Fig.3). Crown preparationof the remaining maxillary teeth was done

[16](Fig.4).

Definitive impression was made using single mixtechnique. Subsequently, provisional prosthesis wasfabricated and cemented (Fig.5).

Definitive casts were articulated in a semi-adjustable articulator after the face bow transfer (Fig.6). Wax patterns were fabricated on the casts after die

cutting for fabrication of the definitive prosthesis(Fig.7).

The definitive prosthesis were placed andfinally cemented in the patients mouth (Fig.8).Patient was given post treatment instructions andreviewed regularly.

Discussion:Dahl deserves credit as he discovered a

significant role for this technique in the managementof the tooth surface loss. The creation of inter-occlusal space significantly reduced the amount of

tooth preparation required.[17] It is from thisbenchmark that other workers have developed lessinvasive techniques to manage this traditionally

difficult clinical problem. Depressingly, it appearsthat there has been limited acceptance and applicationof this technique by the dental profession, despite

favorable reports in the literature for over two decade.Interestingly, the majority of the more recent literature

in this area originates from the United Kingdom.There might be many reasons for the lack ofinternational uptake of this technique. Dentists might

feel more confident in performing conventionalprosthodontic techniques[18-22]and feel that it provides

a more predictable and durable outcome compared


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with the Dahl concept. Practitioners may be cautiousabout adopting the Dahl concept as this techniquemay be in conflict with their traditional taughtprinciples of occlusion. In addition, the remunerationsystem within which practitioners work may dissuadethem from using such a technique

[23,24]. Gough and

Setchell[13]published a retrospective evaluation of theoutcome and factors relating to the creation of inter-occlusal space following TSL, interocclusal spacewere created with the use of an interim appliance. Themain reason for the failure of space creation is poorpatient compliance associated with removableappliances. The studies by Hemmings et al[12], Gowand Hemmings

[25] and Redman et al

[26] relate to the

use of fixed appliance. The use of fixed Dahlappliances has eliminated poor patient compliance asa reason for failure of space creation. The other

reasons for failure of space creation are rare. Thetreatment of the esthetic, social, functional and

economical needs of a partially edentulous patientwith a maxillary fixed partial denture is describedfollowing the lines of the Dahl concept. Not only itfulfills patients desire but is easy and less techniquesensitive. With rapid progression of technology dental

treatment has become out of reach of the commonman especially in developing countries. We still need

treatment modalities which are cost-effective. Thetreatment alternative described maximizes the benefitof Dahls appliance by simplified alteration of the

original prosthesis.

Conclusion:

It is hoped that this article gives the reader anupdate and insight into the Dahl Concept. Althoughthere is a need for further research; the evidence todate indicates that the technique can be confidently

and successfully used in a variety of clinical situations[27]and for many patients, irrespective of age or sex.The development of adverse events is very rare.

[28,29]

If they do occur they tend to be minor in nature andtransient with no long-term adverse sequelae. The

Dahl concept tends to be associated with themanagement of the worn dentition. Simpler treatmentalternatives still can be used to meet functional andpsychological needs of patients and dahls applianceis one such treatment modality. The success and endresult of the treatment largely depends on proper caseselection and patient compliance.

References:

1. Berry D C, Poole D F G. Attrition: Possiblemechanisms of compensation. J Oral Rehabil1976; 3:2016.

2. Smith B G N, Knight J K. An index formeasuring the wear of teeth. Br Dent J 1984;156:4358.

3. Dahl B L, Krogstad O, Karlsen K. An alternativetreatment of cases with advanced localisedattrition. J Oral Rehabil 1975; 2:20914.

4. Carlsson G E, Ingervall B, Kocak G. Effect ofincreasing vertical dimension on the masticatorysystem in subjects with natural teeth. J Pros Dent1979; 41:2849.

5. Ricketts N J, Smith B G N. Minor axial toothmovement in preparation for fixed prostheses.Eur J Prosthodont Rest Dent 1993; 1:1459.

6. Ricketts N J, Smith B G N. Clinical techniquesfor producing and monitoring minor axial toothmovement. Eur J Prosthodont Rest Dent 1993;2:59.

7. Anderson D J. Tooth movement in experimentalmalocclusion. Arch Oral Biol 1962; 7:716.

8. Dahl B L, Krogstad O. The effect of a partial biteraising splint on the occlusal face height. An x-ray cephalometric study in human adults. Acta

Odontol Scand 1982; 40:1724.9. Dahl B L, Krogstad O. The effect of a partial bite

raising splint on the inclination of upper andlower front teeth. Acta Odontol Scand 1983;41:3114.

10.Dahl B L, Krogstad O. Long-term observationsof an increased occlusal face height obtained by a

combined orthodontic/prosthetic approach. J OralRehabil 1985; 12:1736.

11.Bishop K A, Briggs P F, Kelleher M G D.Modern restorative management of advancedtooth-surface loss. Primary Dental Care 1994;

1(1):203.12.Briggs P F, Bishop K, Djemal S. The clinical

evolution of the Dahl Principle. Br Dent J1997; 183:1716.

13.Hemmings K W, Darbar U R, Vaughan S. Toothwear treated with direct composite restorations atan increased vertical dimension: results at 30months. J Prosthet Dent 2000; 83:28793.

14.Gough M B, Setchell D J. A retrospective studyof 50 treatments using an appliance to produce

localized occlusal space by relative axial toothmovement. Br Dent J 1999; 187:1349.

15.Cousins A J, Brown W A, Harkness E M. Aninvestigation into the effect of the maxillary biteplane on the height of the lower incisor teeth.Dent Prac and Dent Record 1969:20.

16.Dawson PE. Functional occlusion from TMJ tosmile design. St. Louis;Mosby, 2007; 2:113-29.

17.Felton D, Madison S, Kanoy E, Kantor M,Maryniuk G. Long term effects of crownpreparation on pulp vitality. J Dent Res 1989; 68(special issue):1009.

18.Evans R D. Orthodontics and the creation oflocalised inter-occlusal space in cases of anterior


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tooth wear. Eur J Prosthodont Rest Dent 1997; 5:16973.

19.Walls A W G. The use of adhesively retained allporcelain veneers during the management offractured and worn anterior teeth: Part 1 Clinicaltechnique. Br Dent J 1995; 178:3336.

20.Walls A W G. The use of adhesively retained allporcelain veneers during the management offractured and worn anterior teeth: Part 2 Clinicalresults after 5 years of follow-up. Br Dent J1995; 178:33740.

21.Bishop K, Bell M, Briggs P, Kelleher M.Restoration of a worn dentition using a double-veneer technique. Br Dent J 1996; 180:269.

22.Chana H, Kelleher M, Briggs P, Hooper R.Clinical evaluation of resin-bonded gold alloyveneers. J Prosthet Dent 2000; 83:294300.

23.Briggs P, Chana H, Kelleher M, Poyser N. Theclinical application of posterior resin-bonded cast

metal restorations. Dental Update 2002; 29:3317.

24.Saunders W P, Saunders E M. Prevalence ofperiradicular periodontitis associated withcrowned teeth in a adult Scottish subpopulation.

Br Dent J 1998; 185:13740.25.Felton D, Madison S, Kanoy E, Kantor M,

Maryniuk G. Long term effects of crown

preparation on pulp vitality. J Dent Res 1989; 68(special issue):1009.

26.Gow A M, Hemmings K W. The treatment oflocalized anterior tooth wear with indirectArtglass restorations at an increased occlusalvertical dimension. Results after two years. Eur JProsthodont Rest Dent 2002; 10:1015.

27.Redman C D J, Hemming K W, Good J A. Thesurvival and clinical performance of resin-basedcomposite restorations used to treat localisedanterior tooth wear. Br Dent J 2003; 194:56672.

28.Murray M C, Brunton P A, Osborne-Smith K,Wilson N H F. Canine risers: Indications andtechniques for their use. Eur J Prosthodont RestDent 2001; 9:13740.

29.Levander E, Malmgren O. Evaluation of the riskof root resorption during orthodontic treatment: a

study of upper incisors. Eur J Orthodontics 1988;10:308.

30.Hellsing G. Functional adaption to changes invertical dimension. J Pros Dent 1984; 52:86770.

Source of Support: Nil

Conflict of Interest: No Conflict of Interest

Received: November 2011

Accepted: February 2012


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