Journal of Dental Sciences

University

University Journal of Dental Sciences, An Official Publication of Aligarh Muslim University, Aligarh. India 100

University J Dent Scie 2017; No. 3, Vol. 1

Case Report

ABSTRACT: Prosthodontic rehabilitation of a patient with maxillofacial trauma often puts

challenge in front of the clinician. A candid technique for rehabilitation of a patient has been

presented with lingually collapsed mandibular jaw and missing anterior teeth due to trauma. A

simplified removable partial denture design has been made with midline split in the prosthesis, to

produce a hinge like action while inserting and removing the prosthesis from the oral cavity. This

design enables the partial denture to adapt closely to the lingual arch overcoming the undercuts

produced by the lingually tilted mandibular posterior teeth.

1 2 3 4Rahul S. Kulkarni, Poonam R. Kulkarni, Rupal J. Shah, Bharti Tomar1.M.D.S. (Senior Lecturer), Dept. of Prosthodontics, Index Institute of Dental Sciences, Index City, Indore 2.M.D.S. (Senior Lecturer), Dept. of Prosthodontics, Sri Aurobindo College of Dentistry and PG Institute, Indore3.Professor& Head, Dept. of Prosthodontics, Government Dental College & Hospital, Ahmedabad4.HOD & Director, The Healers Dental Group, D-215, Vivek Vihar, Phase-1, Delhi

INTRODUCTION : Prosthetic rehabilitation of patients

with maxillofacial trauma has always been a challenging task

for prosthodontists. Fracture of the lower third of the face is

about 60% of the total maxillofacial injuries; with

symphyseal and parasymphyseal fracture contributing 35.3%

of the mandibular fractures. [1]Fabrication of removable

partial denture in patients with lingually collapsed arch due to

trauma is often an arduous job for the prosthodontist. The

most frequently fabricated removable partial dentures are

Kennedy Class I (41.0%) followed by Class III (28.6%), Class

II (25.4%) and finally Class IV (4.9%). Class III are

predominated in the maxillary arch (43.3%), while Class I are

dominated the mandibular arch (55.6%). [2]Another study

revealed class-I in 32.33% cases, class-II in 15.66% cases,

class-III in 33% cases and class- IV in 19%.[3]In one study

custom attachment with stress-breaking effect had been used

for the rehabilitation of long-span Kennedy class IV

patients.[4]There are two major types of removable partial

denture, one is acrylic resin removable partial denture and

other is cast partial denture. But in all types of Kennedy

classes, most commonly used partial denture is of acrylic

resin, because of its ease of fabrication & low cost. [5]In

conjunction with its advantages, it has many limitations, such

as the damage to hard & soft tissues due to gratuitous load

placed on abutment teeth, plaque, and calculus accumulation

on teeth that can cause periodontal problems.[5,6,7]

Lingually inclined molars are common finding in removable

partial denture design in mandibular arch. Nowadays, flexible

dentures are frequently used in such cases,but it has its

limitations in severe undercut areas.[8] Cast partial

removable partial denture's construction in such cases also

faces similar problems, and modification in treatment plan is

often necessary like choosing a labial bar major connector or

contouring of the lingually tipped teeth.[9]The labial bar

major connector often feels bulky to the patient and needs

enough space in the vestibular area for its construction.

Contouring of grossly tipped molars demand for endodontic

treatment and violates the principles of conservation of tooth

structure. Fixed partial denture fabrication for missing teeth

in such cases also faces same problems. Hence an innovative

way to counteract these difficulties has been explained in this

technique.

CASE HISTORY: A 32 years old male patient came to the

department of Prosthodontics, Index Institute of Dental

Sciences, Indore, Madhya Pradesh, India, with chief

A CANDID TECHNIQUE FOR REHABILITATION OF A LINGUALLY COLLAPSED MANDIBULAR ARCH BY HINGED REMOVABLE PARTIAL DENTURE

Keywords :Mandibular fracture, Lingually collapsed arch, Removable Hinged partial denture.

Source of support : NilConflict of interest: None

complaint of difficulty in speech and poor facial appearance

[Fig. 1].

Fig 1. Intra-oral view of the patient with missing teeth and

lingually collapsed arch.

The patient had history of fracture of mandibular symphysis

region 1 year back due to trauma, for which he had been

operated. The re-union of fractured segment with bone plating

had resulted in lingually collapsed mandibular arch due to

irregular reporting by the patient.

Radiographic findings showed a reunited mandibular

symphysis fracture with mini bone plates. Teeth 41 and 42

were present with inadequate bone support at their apices

suggesting a poor prognosis [Fig. 2]. Clinically they revealed

grade III mobility and hence planned for extraction. Patient

recalled after 1 month of extraction of 41 and 42 & a detailed

clinical examination was done. There was no pain and

discomfort associated with the trauma site on palpation. TMJ

examination also revealed no abnormal findings.

Fig 2. Radiographic view of the patient.

On intra-oral examination patient had congenitally missing

33 & 43, & missing 31 & 32 due to trauma from accident &

completely healed extraction socket of 41 & 42. The patient

had poor oral hygiene. The lingually collapsed mandibular

arch produced severe undercut which was challenging for any

prosthetic option to be produced. There was pronounced bone

loss in the edentulous area due to loss of the teeth in trauma.

Healing of the wound due to loss of teeth resulted in

obliterated anteriorvestibule,hence there was not sufficient

space for the labial bar major connector [Fig. 1]. Hence it was

decided to plan a removable partial denture with midline split

to overcome the undercut in mandibular arch.

TECHNIQUE: The present candid technique of hinged

prosthesis fabrication was developed in the Department of

Prosthodontics including Crown and Bridge and

Implantology of Index Institute of Dental Sciences, Indore

(M.P.).

Impressions of the upper and lower arches were made with

irreversible hydrocolloid impression material (Neocolloid;

Zhermack) and casts were poured in dental stone (Type III

dental stone, Moldano, Heraeus Kulzer, Hanau, Germany).

Jaw relation was recorded in conventional manner. A 19

gauge orthodontic wire (Patterson Companies, INC, North

America) was adapted along the lingual surface of the arch

with incorporation of double loop in the midline of the

edentulous space [Fig. 3].

Fig 3. Adapted 19 gauge orthodontic wire along the lingual

surface of the arch with incorporation of double loop in the

midline of the edentulous space.

Jaw relation was recorded in conventional manner. Cross

linked acrylic teeth (Ruby Dental Pvt. Ltd. Jama Masjid,

Delhi) arrangement was done in edentulous space replacing

31, 32, 41, 42 teeth. Congenitally missing teeth 33 and 43

were not replaced due to lack of space. Try in was done in

patient's mouth. After getting approval from patient, wire

with midline loop was then adapted to the mandibular arch

with quick setting polyfix ® cynoacrylate adhesive (Benson

Polymers Limited, Karkar Dooma, New Delhi).

Special emphasis was given to the midline area that contained

the loop. The central incisors were spaced apart with 1mm gap

for proposed future split in the denture [Fig. 4].

Fig 4. Teeth arrangement and flasking

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The flasking of the cast was carried out by conventional

method and dewaxing was done. The wire was inspected for

correct position and the loop portion of the wire blocked by

the polyvinyl siloxane putty (Prime Dental Products Pvt. Ltd.

Kalher, Thane) to prevent inclusion of the acrylic resin in to

the loop [Fig. 5].

Fig 5. After de-waxing silicone putty incorporated in the loop.

Packing was done with heat cured PMMA resin (Acralyn-H,

Asian Acrylates, Mumbai, India) and denture was retrieved

[Fig. 6].

Fig 6. Cured prosthesis with silicone putty.

A midline split was made in the denture with diamond disc

(6934; Brasseler USA, Savannah, Ga) and loop was cleared

off with silicone putty material [Fig. 7,8,9]. It was then

properly finished and polished [Fig. 10].

Fig 7. Prosthesis after removal of silicone putty from loop.

Fig 8. A line drawn on labial and lingual surface of the

prosthesis

Fig 9. Split made on the labial and lingual surface of the

prosthesis

Fig 10. Completed split prosthesis with midline loop.

The fabricated removable partial denture had hinge like

movement in the midline. The lingual flanges of the

removable partial denture (RPD) were pressed with fingers

while inserting it in the oral cavity and released when placed

in position [Fig-11, 12]. Instruction regarding care and

maintenance of prosthesis were given to the patient.

Fig 11. Labial and lingual view of the prosthesis in patient's

mouth.

Fig 12. Patient's appearance before and after prosthesis

placement.

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DISCUSSION: The edentulous space in Kennedy Class IV

patients may be short span (missing incisors only) or long

span (missing anterior teeth & some premolars). In long span

class IV even if the potential abutments are favorable, a fixed

prosthesis would result in an unacceptable cantilever effect.

In Kennedy-Applegate classifications Class IV is the only one

which includes both tooth supported and tooth ridge

supported designs.[10]

Prosthodontic rehabilitation of a patient having maxillofacial

trauma often warrants special consideration. In present case,

mandibular arch exhibits 'v' shape, causing increase length of

the edentulous span for the replacement of the missing teeth.

Flexure of long span bridges during mastication can be a

problem. A very long span fixed prosthesis during centric

closure with no food in the mouth may present no real

problem in terms of flexure, because there is distribution of

forces among all the occlusal surfaces around the arch.

Nevertheless, when bolus of food interposed between the

pontic area of long span bridge and its opposing occlusal

surfaces, the effect can be quite different since the occlusal

contacts on the opposite side of the arch have not yet come

into play. In this case, all of the force is concentrated on the

bridge span, inducing a strain that the restoration and / or the

abutment teeth may not be capable of withstanding. In a cross-

sectional study of the lifespan of fixed prostheses, Schwartz et

al reported that the best longevity for fixed prostheses was

when canines were used as abutments.[11] In present case

lingually collapsed mandibular arch produces difficulties in

prosthesis fabrication because of severe lingual undercut.

Hence, modification in conventional techniques is required to

produce a successful prosthesis. A two part hinged denture

produces satisfactory solution but produces difficulties in

regular maintenance of a prosthesis [12]. A 19 gauge wire

gives sufficient rigidity to the prosthesis but long term follow

up is required regarding durability and effectiveness.

Technique given in this article is not technique sensitive and

easy to follow.

Advantages of this ingenuous technique are: This is a very

simple technique for both patient & dentist because there is no

need of surgery. This technique does not cause any damage to

the adjacent teeth, as in fixed partial denture and in cast partial

denture, preparation of adjacent teeth usually requires. Single

or multiple teeth can be replaced by this technique. Partial

denture fabricated by this technique can be aesthetically

pleasing in overall appearance. This technique is not time

consuming, a partial denture can be fabricate in single day

only.

Disadvantages of this ingenuous technique are: Removable

partial denture fabricated by this technique needs frequent

replacement because of the shrinkage of the bone & tissues

denture will become least retentive. There can be a food

lodgement in the loop of the wire that may irritate the patient.

Conclusion:

For the Class IV type of partially edentulous arch treatment

approaches may include explicit indications for fixed or

removable partial dentures, with the removable partial

denture having greater flexibility as a treatment modality for

conditions other than normal. While rehabilitating Class IV

type of partially edentulous arch the dentist can face a

biomechanical and cosmetic confront. This observation

increases more certainty when examined in a longitudinal

biomechanical perspective.

ACKNOWLEDGEMENT : The authors are very thankful

for Support from The Department Of Prosthodontics, Index

Institute of Dental Sciences, Index City, Indore -452001,

Madhya Pradesh, India, where the work was primarily carried

out.

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CORRESPONDING AUTHOR:

Dr. Poonam R. Kulkarni

8-A, Krishi Vihar Colony, Near Tilak Nagar, Indore

452001, M.P.

E mail: poonamrahulkulkarni@gmail.com

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