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             The        Monthly     E- Journal Of  Dentistry                  Vol -  V I   Number-    X I I   December  2011     ISSN   2230 – 9489 (e)

In this Issue:

  • Scientific Editorial - Laws for Finding Pulp Chambers & Root-Canal Orifice - A review  - Dr.Syed Nabeel

  • REHABILITATION OF A MAXILLECTOMY DEFECT BY A CAST METAL OBTURATOR.-. Dr.Syed Ali Peeran. et.al

  • ADENOMATOID ODONTOGENIC TUMOUR – A REVIEW  -  Dr Chaitanya N Babu. et.al

  • Dental Archieves  -  New Orthodontic Method Still Needs Oral Hygiene .‎
    The Telegraph - Sep 28, 1977

     

Scientific Editorial:

Laws for Finding Pulp Chambers & Root-Canal Orifice - A Review

Dr.Syed Nabeel

 Editor In Chief :

Dental Follicle - The E Journal Of Dentistry

Founder and CEO DentistryUnited.com

Director : Smile Maker Clinics Pvt. Ltd

INDIA

 

Abstract : Application of the laws of finding the pulp chambers and the root canals orifice helps in the proper delivery of the treatment. Knowledge of the same among the general dentists,  in general has been emphasized in the goodwill  of the patients. The laws are briefly summarized in this short communication.

Key Words :Law of centrality, Law of concentricity ,Law of the CEJ , Law of symmetry, Law of Color Change, Law of orifice location, Root Canal , Root  canal Orifice   

Introduction :The endodontic triad consisting of biomechanical preparation , microbial control and complete obturation of the canal space remains the basis of the endodontic therapy.1 Many  failures in the treatment are because of the non application of the basic principles at every step, as well as not applying  of  laws for finding pulp chambers and root-canal orifice. 2

The Laws propsoed by Paul Krasner and Henry J.Rankow2 are as follows :

 

  • Law of centrality: The floor of the pulp chamber is always located in the center of the tooth at the level of the CEJ

  • Law of concentricity: The walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the CEJ

  • Law of the CEJ: The CEJ is the most consistent, repeatable landmark for locating the position of the pulp chamber.

  • Law of symmetry 1: Except for maxillary molars, the orifices of the canals are equidistant from a line drawn in a mesial-distal direction through the pulp-chamber floor

  • Law of symmetry 2: Except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction across the center of the floor of the pulp chamber

  • Law of Color Change: The color of the pulp-chamber floor is always darker than the walls

  • Law of orifice location 1: The orifices of the root canals are always located at the junction of the walls and the floor

  • Law of orifice location 2: The orifices of the root canals are located at the angles in the floor-wall junction

  • Law of orifice location 3: The orifices of the root canals are located at the terminus of the root developmental fusion lines


Conclusion :

   By the commercialization of the research and coming up of various rotary systems and the usage of the same by many dentists had lead to many failures which are inadvertently due to the lack of basic anatomic knowledge of the pulp chamber and the root canal. Understanding of the same and application will help the dentists to use the right files irrespective of them being hand or rotary and deliver better results.
 

References :

1.Cohen S, Hargreaves K. Pathways of the Pulp 9th edition Mosby, St. Louis, MO, 2006.

2.Paul Krasner, DDS, and Henry J. Rankow, DDS , Anatomy of the Pulp-Chamber Floor ; JOURNAL OF ENDODONTICS ; VOL. 30, NO. 1, JANUARY 2004 page 5-16

 

 

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REHABILITATION OF A MAXILLECTOMY DEFECT BY A CAST METAL OBTURATOR
 


 

1.Dr.Syed Ali Peeran.
Assistant Professor, Dept of Prosthodontics,
Faculty of dentistry,
Gezan University, KSA.

2. Dr.Vidya Shankari ,
Senior Lecturer,
Department of Prosthodontics,
Vinayaka Mission’s Sankarachariyar Dental College,
Salem, Tamil Nadu, India.
 

 


Dental Follicle -
The        Monthly     E- Journal Of  Dentistry                  Vol -  V I    Number-   X I I    August  2011     ISSN   2230 – 9489 (e)

ABSTRACT:

Rehabilitation of a patient with maxillectomy defect is a highly challenging task. The disfigurement associated with the loss of facial structures and functions causes significant emotional stresses and physical burdens.The treatment of choice includes the fabrication of a definitive cast partial metal obturator. This paper describes the technique, advantages and limitations of fabricating a cast metal obturator.

Key-words: maxillectomy, obturator, cast partial denture.

INTRODUCTION:

Partially edentulous maxillofacial patients are those who suffer extensive loss of supporting bone due to an extensive surgery for a tumour or traumatic jaw injury. In  many instances,  the  patient  have  such  a gross jaw  defect that  a  complete denture  could be unmanageable,  but a prosthesis stabilized by  the  remaining teeth would  be functionally adequate.

However the problem of obtaining satisfactory  denture support are  generally     difficult  as  there  is  reduced capacity  for  residual teeth  and tissue to provide cross support,  stability  and  retention (2).  In all the partial denture  treatment  we strive  to  preserve  the health of  the  remaining  teeth, by not subjecting  them  to stress  exceeding  their  physiologic limit.  This is the  greatest  problem  in  Maxillofacial defect  patients  in  whom  the ridge tissue  is more resilient and displaceable than that of a  badly  resorbed ridge. Hence the design should be taken into account for planning the   prosthesis which would replace the lost tissue and structure. 

The protocol for rehabilitation of such cases has been discussed in  this  case report  relating  to  a  patient  with  Aramany  class defect  by  a definitive  cast  partial  metal obturator.

CASE REPORT:

A 27 year - old female patient reported to the Department of Prosthodontics with a chief complaint of loose maxillary prosthesis. Her past medical history revealed that she had undergone left partial maxillectomy as a treatment of choice for carcinoma on the left palate 2 years back.

Intra oral examination showed a post surgical defect size of 6 x 4 cm in the region of left maxilla and hard palate

 

 

 

 

 

 

(Fig 1:  Pre operative view).

 Teeth missing were upper premolars and molars on the defect site. The defect was not crossing the midline and was classified as Aramany Class II (1). The remaining teeth were all caries free, non mobile and confirmed by radiographs and are sound to be taken as an abutment.
The case was evaluated by the board of prosthodontists for maxillofacial rehabilitation. Treatment plan includes the mouth preparation, followed by definitive Cast Metal Obturator

.
 PROSTHODONTIC PROCEDURE
The patient was asked to relax comfortably in the dental chair tilted at an angle of 45°. Hydrated cotton ribbon gauge was placed all around to block out the defect. Upper and Lower alginate impressions were made and diagnostic cast obtained and surveyed. The defect was outlined on the diagnostic cast and a special tray made using auto polymerizing acrylic resin under a uniform 2 mm thickness wax spacer.

 

(Fig 2: Border Moulded Special Tray

 

 

 

 

 

 

Embrasure clasp was planned in relation to 16 and 17.  Hence occlusal rest seat prepared on the distal side of 16 and the mesial side of 17.  Canine rest preparation done in relation to 13 to serve as is indirect retainer and an i - bar was planned in relation to 23. The defect site was border molded along the special tray and a final impression was made by the dual impression technique using addition silicone impression material.
 

     

 

 

 

 

 

 

 

(Fig 3: Final Impression)

 

 

 

 

 

 

 

 

 

 

Fig 4 : Master Cast

A master cast was obtained and carefully inspected for any surface defects and bubbles. The master cast was then surveyed and arbitrarily blocked out with clay and block out wax.  Duplicating was done using reversible hydrocolloid and a refractory cast obtained.

The framework was designed and waxed onto the refractory cast.  The design incorporates full palatal coverage except the defect area and also includes an embrasure clasp assembly in relation to 23. The pattern was cast in basemetal co-cr alloy and the framework obtained.  

 

 

 

 

 

 

 

 

 

Fig 5: Cast Partial Framework and Occlusal Rim on Master Cast

After finishing and polishing, a metal try in of the framework was done.    Autopolymerising acrylic resin was used to fabricate a temporary denture base on the framework, a jaw relation was recorded, and mounted on the articulator. Block - out of the defect with 2 mm uniform thickness was done. Autopolymerising acrylic resin was mixed and flowed onto the blocked out area and merging with the metal framework thereby to obtain the optimal palatal contour.  Acrylic resin teeth were placed on the denture base.

        Once the trial was found satisfactory, flasking,  dewaxing  and  packing were done as per the prosthodontic protocols. Finishing and polishing done and during insertion of the prosthesis, the obturator portion is relined with permanent soft liner.  The patient was asked to do the necessary functional movements while the prosthesis is in place

 

 

 

 

 

 

 

 

Fig 6: Post operative view

        Post insertion examination was  done at one week and three month intervals and the patient has been functioning normally.

DISCUSSION:

This case represents a typical Aramany Class II defect which generally provides a favourable situation for the prosthesis construction as the remaining teeth are all present.  Also the defect doesn’t cross the midline as in the classical resections.  The defect was unilateral and the anterior teeth are all left intact and thereby adds a great value for the aesthetics .The cross arch stabilization  was  achieved  by  the tripodal removable  prosthetic design (1&4).    A  full  palatal  coverage  major connector design was used  along with  the guide planes  and  definitive rest seats  which  enhances  the stability.  Retention was best achieved by the use of Embrasure clasp.  Though wrought wire circumferential clasp may  minimize  the horizontal force acting on  the abutments (3), embrasure clasp seems to be the best for the presented case,  since  the encirclement clasp is comparatively more than others,  which decreases  the leverage  forces falling on the abutment.

Co - Cr base metal alloy was used thereby to reduce the weight and thickness of the major connector to improve the comfort value for the patient. Permanent  soft liners  were  added  to  the  bulb portion of  the obturator  to simulate the functional movements of  the tissue on  the defect side.   This further engages the undercut of the defect to obtain additional retention and support. The prognosis  of  this case is  satisfactory, as  with  the increase  in  the  number of  teeth,  for  good  retention,  stability  and support with minimized prosthesis movement.

 

CONCLUSION:

Prosthodontists trained in maxillofacial rehabilitation have consistently faced the challenge of restoring form, function and esthetics. Rehabilitation of a patient with maxillofacial defect has been described in detail in this report by using cast metal - acrylic obturator.  The rehabilitation resulted in improved function, esthetics and comfort to the patient, thus enabling them to lead a normal life.  These custom made prosthesis are highly successful as compared with any other treatment, the important feature is to be aware of the principles and to stick on them.


REFERECES

1. Aramany A. Basic principles of obturator design for partially edentulous patients, Part I: Classification. J Prosthet Dent 1978; 40: 554 -57.
2. Kelly EK. Partial denture design applicable to the maxillofacial patient. J Prosthet Dent 1965; 15:168 - 73.
3. King GE, Marbn JW. Cast circumferential and wire clasps for obturator retention. J Prosthet Dent 1983; 49: 799- 802.
4. Walter JD. Obturators for acquire palatal defects. Dent Update 2005; 32: 277-85.

 


 

ADENOMATOID ODONTOGENIC TUMOUR – A REVIEW


1.Dr Chaitanya N Babu

Professor.

Department of Oral and Maxillofacial Pathology

Oxford Dental College and Hospital


2.Dr Sindura C.S

Oral Pathologist

Apt 201, Inland Empress

1 st Cross, T.P.Venugopal Layout

R.T.Nagar

Bangalore

E mail ID: sindurarajesh@yahoo.com

 


Dental Follicle -
The        Monthly     E- Journal Of  Dentistry                  Vol -  V I   Number-   X I I      December  2011     ISSN   2230 – 9489 (e)

ABSTRACT:
Adenomatoid Odontogenic tumour (AOT) is an uncommon odontogenic tumour which has been categorized as Hamartoma and sometimes a true neoplasm. This article emphasizes the histogenesis, clinical and histopathological entity of AOT, which could prove to be decisive in its designation

KEY WORDS: Adenomatoid Odontogenic Tumour, Hamartoma, Neoplasm


INTRODUCTION:

Adenomatoid Odontogenic Tumour was described by Steensland in 1905 1.It is an uncommon tumour originating from odontogenic epithelium constituting 3-7% of all odontogenic tumours 2.Whether to regard AOT as an Hamartoma or a true neoplasm has been a controversial issue for long.AOT has been used under various terms like Adenoameloblastoma,odontoma,epithelial tumour associated with developmental cysts, tumour of enamel organ epithelium, Adenomatoid ameloblastoma, pseudoadenomatoid ameloblastoma, cystic complex compound odontoma, unusual Pleomorphic adenoma like tumour and ameloblastic adenomatoid tumour2
This article provides an extensive review of Etiology, Clinical features, Radiological feature and Histopathogenesis of AOT.

VARIOUS TERMS USED IN PAST TO DESIGNATE AOT:

ADENOAMELOBLASTOMA:
The term Adenoameloblastoma appeared in the literature in 1950 in an article by German and Tiecke. It described what they concluded to be histopathological variant of ameloblastoma. It was considered to be Ameloblastoma because of its similar behavior .Moreover, at that time both were treated by simple enucleation 3. In 1957 Lucas questioned the relationship of this tumour to Ameloblastoma. Through increased knowledge of its behavior and clinical presentations it became apparent that Adenoameloblastoma was indeed a separate entity, with younger age propensity and more specific location. Even more significantly, Adenoameloblastoma was an encapsulated cystic structure that was curable by enucleation, whereas ameloblastoma was infiltrative and was curable only by resection. In fact the former represents the cyst and latter represents the true neoplasm 3

ODONTOGENIC ADENOMATOID TUMOUR (OAT) AND ADENOMATOID ODONTOGENIC TUMOUR:

 In 1958, Gorlin and Chaudly, in their discussion of adenoameloblastoma emphasized the appropriateness of the term and pointed out the distinct difference between the two lesions. To distance the adenomatoid lesions form Ameloblastoma, the terms OAT and AOT were introduced. Overtime the catchy abbreviation AOT prevailed, which unfortunately is also incorrect 3.

 ADENOMATOID ODONTOGENIC CYST:

 Robert Marx and Diane stern in 2005 mentioned that AOT is not a tumour but rather a cyst that has hamartomatous intraluminal proliferation of epithelial cells, derived from Hertwig’s epithelial root sheath. While at times this proliferation may fill the lumen to give the impression of solid tumour, a close impression will reveal its emergence in the epithelial lining. The calcification seen in these cysts which represents attempts of root sheath epithelium to induce root dentin has been identified as dentinoid material. Therefore they said that the most appropriate term is Adenomatoid Odontogenic Cyst 3.

 In the 2005 WHO Histologic typing of odontogenic tumours, the AOT has been defined as: “A tumour of odontogenic epithelium with duct like structures and with varying degrees of inductive change in the connective tissue, the tumour may be partly cystic and in some cases, the solid lesion may present only as a masses in the wall of large cyst, its generally believed that the lesion not a neoplasm”4

 ETIOPATHOGENESIS:

 In order to conceptualize a unified source of origin for diverse locations of AOT, only the complex system of dental laminae or its remnants matches the requirement 4. There is a continuous debate in the literature, whether to regard AOT as a developmental outgrowth, hamartoma or a true neoplasm of odontogenic epithelium 4

Many authors agree to an odontogenic origin which appears logical due to abundance of odontogenic epithelium in the region where the lesion is found. i.e.: the tooth bearing areas of the jaws. The Histologic characteristics of the lesion too resemble odontogenic epithelium in various degrees of differentiation 2

The fact that all AOT variants show identical histology strongly points towards odontogenic origin 4

The AOT is a cystic hamartoma arising from odontogenic epithelium. It will characteristically have a lumen lined by epithelium from which proliferations fill much and sometimes all the lumen space, then mimicking a solid tumour 3

Philipsen HP et al have quoted that ‘‘such a controversy is irresolvable because sound arguments can be advanced in favor of both the hypothesis the arguments being based on personal bias rather than scientific evidence’’ 4

Recent ultrastructural and enzyme histochemical studies suggest that AOT originates from Enamel organ epithelium 5

 CLINICAL FEATURES:

 A.   FREQUENCY :It has been estimated that AOT accounts for approximately 2.9 – 6.8 % of all odontogenic tumours 4. It gives tumour a ranking of 4th or 5th among the odontogenic tumours surpassed by odontomas, myxomas, ameloblastomas and /or cementoosseous tumours or lesions 4.

 B. AGE: AOT mainly occurs in younger age groups, the youngest age group being reported is 5 yrs 6. The age range of patients is between 3-82 yrs at the time of diagnosis. Approximately 2/3 rd of tumours are diagnosed in 2nd decade of life. The age distribution is very narrow and this makes AOT truly unique among odontogenic tumours 4

 C.GENDER : The female to male ratio of for all age group together is 2:1 4

 D. RACE : AOT is described in all major races 4

 E.SITE : The lesion can be central or very rarely it can be peripheral .The central variant is classified as follicular / extrafollicular types 4. The follicular variant is associated with crown of embedded tooth, most frequently a permanent upper canine; the extrafollicular variant has neither pericoronal nor any relationship to the embedded tooth.

The peripheral type is located in gingival mucosa .The central variant accounts for 98% of all AOT s of which 72.6% are of follicular type. The two central variants are common in maxilla than in mandible with ratio 1.9:1.On the other hand peripheral variant is extremely rare in the mandible.

 AOT is sometimes referred to as 2/3 rd tumour because 2/3 rd occur in maxilla , 2/3 rd occur in young women (preteen and teenage years )2/3rd associated with unerupted tooth,2/3rd of those teeth are canines, 2/3rd of statistics vary slightly but the rough distribution is accurate3

 F.CLINICAL PRESENTATION:All types of AOT appear as slow but progressive growth with few or no subjective symptoms.  Cortical expansion is common finding in central variants and penetration of cortical plate has rarely occurred 7

The lesion particularly extrafollicular type may cause some displacement of neighboring teeth, although root resorption is rare. Sometimes unusually large tumors which are regarded as neoplasm rather than hamartoma are reported  7. The size of introsseous lesion varies between  1-3 cm in diameter.

 RADIOLOGICAL FEATURES:

 The intraosseous variants appear as well demarcated radiolucencies. In approximately 2/3rd of the cases, radiolucency contains small particulated radiopaque foci. It has been indicated that intraoral radiographs are essential for diagnosing AOT in the presence of minimal quantities of calcified deposits 1

Rather than surrounding only the tooth crown the AOT frequently extends laterally from one surface of unerupted tooth to envelop a considerable portion of the root.

The extrafollicular type appears as a radiolucency without any pericoronal relationship and is located between above/superimposed upon roots of erupted permanent teeth 1

The peripheral type may show slight erosion of the alveolar bone cortex but rarely produces radiographically detectable changes 4.AOT may show displacement of roots of adjacent single rooted teeth, although resorption of roots is a rare phenomenon.

 HISTOPATHOLOGY:

 The tumour cells may be in nests / whorls intermingling with each other 2. The cuboidal /columnar cells forming duct like pattern may be rimmed on the lingual side with eosinophilic material, the lumen may be empty or contain cellular debris. These ducts like structures may in some areas show changes from definite columnar or cuboidal to sphindle variety 2

In many areas tall columnar cells are seen to line these duct like areas in double layers with ring like eosinophillic material intervening between them2.The central part of this structure show stellate reticulum like cells and squamous cells either alone or with each other. In these double layered columnar cells the nuclei are away from intervening eosinophillic material 2. The nuclei are mostly round or oval and sometimes may be sphindle shaped.

Some polyhedral and eosinophillic tumour cells of squamous appearance exhibiting well defined cell boundaries and prominent intercellular bridges may be occasionally found. The nuclei may show very mild (degenerative) pleomorphism2.

Due to presence of these polyhedral squamous type of cells ,eosinophillic material and calcifications, many cases have been published as combined AOT /CEOT recently 8.However Philipsen et al has strongly warned against such confusion “merely on the grounds that a certain histoarchetectural pattern from one (biologically separate )odontogenic tumour occur in another ,likewise biologically separate odontogenic tumour 2

 

Globular calcified material may be found in islands of squamous type cells .These materials have been speculated as Enameloid, Dentinoid, or Cementoid 2

 

Fig 1: Ring form within 2 layers of cells

Fig 2: Lining from luminal side of single layer of cells

Fig 3: As a mass within the nodule

Fig 4: As a network within single layer

Fig 5: As a network or mass within double layer

Fig 6: As isolated droplets within the nodules of cuboidal cells

Fig 7: Isolated droplets within the nodules of sphindle cells

However within the interlacing cords of epithelial cells between the nodules, droplets of eosinophillic material may be found 2
Philipsen et al believe that the various histopathologic patterns observed in AOT reflects a continuous spectrum rather than discrete or separate tumour entities2



CONCLUSION:

The histogenesis of AOT still remains uncertain. Some categorize it as hamartomatous lesion and some consider it as true neoplasm because of its unusual large size. This review will hopefully spawn further studies in this regard and thus resolve its controversial histogenesis as to whether it’s a hamartoma, true neoplasm or odontogenic cyst.
         

References:
1. Jorg G.K et al, AOT of mandible: Review of literature and report of a rare case, Head and face medicine, 2005, vol 1, No 3 , Pg 1-5
2. Amit Chattopadhyay, AOT A review of literature and report of 30 cases from India Indian journal of dental research ,1994,vol 5, No 3, Pg 89-95
3. Oral and maxillofacial pathology, Chapter 20: Where have all the great terms gone? Diane stern and Karl marx, 2003, 1st Edition, Pg 814
4. Philipsen H.P et al The adenomatoid odontogenic tumour – An update, Oral med pathol 1998 , vol 2 , Pg 55 – 60 , ISSN 1342 – 0984
5. Zohair Haider, Adenomatoid odontogenic tumour – Case report, The Saudi dental journal, Sep dec 1997, Vol 9, No 3, Pg 144-148
6. Deepti Garg et al, AOT – Hamartoma or true neoplasm: A case report, Journal of oral science, 2009, Vol 51 , No 1 , Pg 155-159
7. Geist S.M.Y and Mallon H.L. AOT A report of unusually large lesion in the mandible, Journal of oral and maxillofacial surgery, 1995, Vol 53, Pg 714-717
8.Slar G.H , Ng Kh ,Combined calcifying epithelial odontogenic tumour and AOT ,International journal of oral and maxillofacial surgery, 1987, Vol 16, Pg 214-216

 

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Dental Archieves

                                                
New Orthodontic Method Still Needs Oral Hygiene .‎
The Telegraph - Sep 28, 1977