lecture 4 ,other disorders of teeth (script)

8/3/2019 Lecture 4 ,Other Disorders of Teeth (Script)

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Oral pathologyLecture#4Other disorders of teeth

We will start talking about eruption and

shedding of the teeth.SLIDE#2.

We talked about developmental changes inteeth; one of these is premature or delayederuption of teeth:

Premature eruption: natal and neonatal teeth,now natal teeth eruption happens at birth,

while neonatal teeth eruption happens within1 month after birth.Now natal and neonatal are deciduousdentition ,they have enamel and dentine butthe tooth germ is superficially located, thelocation of tooth structure is superficial, sothey are very close for eruption , as aconsequence they erupt prematurely .so thecause of premature eruption is the superficiallocation of the tooth germ. In these teeth theenamel and dentine of the crown are normal,but there is an absence of root formation,may be because of premature eruption ,andthe superficial location of the tooth ,buteither or the root formation is absent ,or

there is minimal root formation.Prognosis: the future of those teeth either

shedding by themselves, or they should beextracted if there are any complications.


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Thepictureabov

e:individual with a single tooth which is eithernatal or neonatal, its deciduous teeth that isprematurely erupted, because of superficiallocation of tooth germ.

Now in pathology you need to understand thepathogenesis of the condition ,in oral

medicine you can know that this tooth iseither natal or neonatal ,and in the case oforal surgery you can determine if this toothneed to be extracted or it will be lostcontinuously by itself ,but in pathology youneed to know the causes of natal orneonatal ,and also the general treatment outlines ,but most important thepathogenesis .So the pathogenesis here is

superficial location of tooth germ.SLIDE#4..

Now delayed eruption or retardederuption..

From the previous lectures we could say thatsometimes when you look at the patient

mouth you will see that there are no teethbut when you take a radiograph you will seea lot of unerupted teeth .Now delayederuption is caused by:


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1.One of the students said the fibrosis ofgingival and that is possible (DR.said(

2.Crowdning of teeth so there is no space.In general delayed eruption may be associatedwith:

3.Endocrinopathies which is the decreasing in

the growth hormones, in pituitary glandhormones and that may delay the teetheruption in general, either its primary orpermanent.

4.Nutritional deficiencies.5.Down syndrome (in which there is mental

retardation and retardation in teeth eruption.

6.trumatic displacement of tooth germ, as wesaid in premature eruption there issuperficial location of tooth germ, while indelayed eruption there is dislocation in tooth

germs.That means sometimes the tooth germ beforeit forms it may be displaced for areason oranother, and this displacement means that itgoes far away from eruption ,that could giveus delayed eruption ,otherwise when itssuperficial displacement it will givepremature eruption, sometimes the crownmay be too big due to gemination or fusionso the space will be not enough for the toothto erupt ,in case of cleidocranial dysplasia we

said that retarded eruption is due to multiplesupernumerary impacted teeth ,crowding,loss of space ,all of these will delay theeruption of permanent teeth.

Slide#5..


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Premature loss of teeth.We said that hypophosphatasia is one of thecauses of premature loss, where there isdecrease in the enzyme hypophosphataseand what is going on here in this case is thatcementum formation is almost absent, their

is no encouragement in the socket for toothto erupt, because we all know that the PDL innormal teeth make there insertion incementum,so in the case where there is nocementum to make insertion in there will beearly loosening of teeth. what else causespremature loss of teeth?

1.Dentine dysplasia type1 2.periodantal diseases and inflammation wherethere will be pocketing and spacing aroundthe tooth and causes loosening of the toothlike people who have PDL disease they havemobile teeth, and there will be drifting to oneside because of this mobility.

Dental caries will eat the tooth and there willbe loss of the tooth (crown) from the oralcavity and then caries will go down to theroot and finally the tooth will be gone.

SLIDE#6Persistence of deciduous teeth.

Now why sometimes there will be persistenceof deciduous teeth? Sometimes the child

doesn't change the teeth .the permanentdoes not appear on 6 or even 7 years of age,why is that?

May be there is no permanent teeth at all,because we all know that shedding of


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primary teeth depends on the growth ofpermanent dentition or the force of thepermanent dentition, as one factor ofshedding of deciduous teeth not the wholeprocess caused by permanent, but the failureof eruption of permanent teeth causes the

delayed in the process of shedding ,why wehave failure in eruption of permanent teeth,they may be originally missing or displaced.The DR said that there is a patient came tothe oral diagnosis clinic and he still havingdeciduous canine. The is still there butwhere is the (3)? It will be either horizontally

impacted or displaced, it's not giving theforces of eruption so that the deciduous will not be shaded so failure of eruption.Tooth that may be displaced like max.canine,or missing like the (5).sometimes the secondpremolar is congenitally missing, so the (e)may still there for along time .now when allthe deciduous dentition stay for a longtimethan it should be? Answer: in a case likecleidocranial dysplasis .when there are a lotof mechanical causes to impact thepermanent ,like ;no spaces ,supernumeraryteeth etc ,as a consequence so a lot ofpermanent teeth will not erupt and a lot ofdeciduous teeth will stay there. One of the

students asked could we find deciduous andpermanent tooth at the same time.

Answer: may be, when the tooth germ ismisplaced. The lateral incisor may eruptpalatally and the (b) labially, but eventually


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the pressure of the permanent with themotion of the tongue will cause thedeciduous to be missed because thepermanent tooth tends to return to its

original area.SLIDE#7..

Impaction of teeth.What's the meaning of impaction?

Delayed eruption beyond the normal time. whythe tooth may be impacted?

1.Gingival fibrosis2.Loss of the space

3.Big crown

4.Abnormal angulations of the tooth may beinclined mesially or distallyComplications

Odontogenic tumour , odontogenic cyst.Now the radiograph is your way to figure outimpacted teeth, crowding, odontogenic cystor tumor.

If the problem retains deciduous teeth and wetook a radiograph and all the permanentteeth are there ,no obvious problem ,noimpaction no supernumerary, no mechanicalproblems ,then we would think abouthormonal changes ,may be there is reducedlevel of a certain hormone that does give thedrive for permanent teeth to erupt. May be,

its the growth hormone that is affected, soevery thing will be retarded. The teeth thatare most commonly impacted; canine, thirdmolar, premolars which are most likely to bedelayed in eruption.


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If I have a mandibular third molar which isimpacted , I will not leave it there ,because Idont want to expose my self to odontogeniccysts ,or odontogenic tumors ,and I dontwant the impacted 8 to cause pressure on my7 the second molar, so the complication is

causing pressure on the surrounding teeth,after the pressure on the surrounding teeth,and the pressure on the adjacent teeth therewill be absorption of the root and later on the7 may be extracted so we dont want to looseadjacent teeth.

SLIDE#8.Reimpaction of teeth.Now the tooth may starts eruption but stops ata certain level, and then the adjacent teethmay incline over it, this is called submergedtooth. The submerged tooth is usually the (e)which is primary second molar .what happensis that the tooth starts to erupt, andankylosis occurs.What is ankylosis?

Answer: fusion between cementum and thebone, and you know that the PDL is normallylocated around the cementum. In ankylosiscementum and bone fuse without the PDL inbetween, so the tooth does not erupt further

and as a consequence the alveolar process isnot fully developed. Look at the picturebelow:


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This tooth is below the level of occlusion itstarted to erupt but at a certain level itstopped, may be due to ankylosis, thesurrounding bone is not reaching the normallevel, as consequence the erupting teethtend and try to close the space. We will facethis case in the clinic, usually we dont findthe (5).The teeth that are mostly congenitallymissing are 5, 8, and sometimes lateral

incisor, when the 5 is missing it mayassociated with infra occlusion or retentionof the deciduous tooth, so what's thedisadvantages?

First it will affect the occlusion, and the foodwill accumulate in the spaces, periodontaldiseases, caries .so submerged is a synonyms

to infra occlusion.So ,my colleagues all what we have talkedabout is a revision for the last three lectures,beside this is not what pathology is ,this islike apiece of cake the real pathology is lateron (wa ma 5afia kan a3tham(

SLIDE#9..

Non-bacterial loss of tooth structure..Now what does caries mean?Its the loss of the tooth structure due to acidsand these acids come from bacteria workingon food particles. We have loss of toothstructure due to non-carious causes, which

Submergedtooth,

Submerging


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include attrition, abrasion, erosion,resorption.

AttritionIt is the loss of tooth structure due to tooth totooth contact. It may be physiologic, whichinclude age. There is always tooth to tooth

contact and age is one of the physiologiccauses. Attrition is located on the incisaledges, occlusal surfaces of molars, and forthe upper teeth palatal cusps and for

mandibular it's on the buccal cusps.We talked a little pit about occlusion in dentalanatomy last year and we recognized the way

of occlusion, which I could describe it as thefollowing, the buccal cusps of the uppermolars located buccally and the palatal cuspsof the upper molars located in the centralfossa of the mandibular teeth .actually theparts that are responsible for masticationand function of the tooth are palatal cusps ofupper molars with buccal cusps of lowermolars, and in these places the attritionoccurs, because there is a heavy load onthem. What we will find on these parts arewearing facets (cup shaped,surrounded byenamel. Why its cup shaped not flat?

Answer: because the dentine is softer thanenamel, so the dentine in the middle will be

wearing faster than enamel and we will havea cup shape appearance of the tooth due tophysiologic action of the attrition one of thefactor that increases attrition is the hard


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food . Look at the picture below and noticethe cup shaped appearance of the teeth:

Now the pathologic actions which increase theattrition:1.The habits of bruxism (clenching); putting

the teeth in occlusion for along time.2.Abnormal acclusion there will be no balance

between loads on the parts of the tooth.3.Abnormal tooth structure; abnormal enamel

or abnormal dentine like amelogenesisimperfecta.

In amelogenesis imperfecta the tooth loss willbe highly accelerated, this is pathologic notphysiologic, the physiologic is only due tonormal mastication. In pathologic causesthere are other factors like misalignment ofteeth, habits of bruxism, and the abnormal

tooth structure. The response of our teeth toattrition is the formation of secondarydentine to protect the pulp, by surroundingthe pulp champers with dentine. Because

Tooth wear with alarge element of

attrition cu sha e


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when dentine is lost substances will godirectly to the pulp and cause pulpitis.

Now the exposed dentine will be discoloredbecause you know that dentine relatively hashigher organic material than enamel, so itwill stain easily and there will be

hypersensitivity due to the movement of thefluid in dentinal tubules which will causepain. Because the tooth forms secondarydentine in the case of attrition around thepulp many people have attrition without anykind of sensitivity. Another reaction causedby attrition is the closure of dentinal tubules

to protect the pulp. SLIDE#13..Abrasion..

Its the loss of the tooth structure due tofriction of other bodies, like tooth brush,pencils, hair grips holding, pipe smoking, soits pathologic wearing of tooth due to frictionof other particles.

What increases the abrasion by tooth brush isthe tooth paste it self if it has hard particlesit will accelerate the abrasion, which type ofbrushing will increase the abrasion? its thehorizontal way in tooth brushing.Clinically:

The abrasion is wedge shaped it has sharp

edges like inverted pyramid, and the dentinit self is polished and shiny from tooth

brushing.The areas that carry a heavy force are thecanine and premolars areas ,because of that


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canine is a very important tooth ,when thereis abrasion ,heavy occlusal load may inducefurther fraction of the enamel, this is calledabfraction, so abfraction is the fracture ofenamel due to flection (not sure) its type offorce applied to hard structure like enamel

,enamel does not tend its brittle ,and thisbreakdown of enamel on heavy load areas iscalled flection. These pictures show abrasion

due to wrong teeth brushing..

Note that the abrasion is on the cervical thirdof the teeth, because of the wrong method intooth brushing, heavy occlusal load on canineand premolar may induce fracture cervically.It's already weakened by abrasion but theocclusal surface may be fracture.Now let's talk about habitual abrasion other

than tooth brushing, the pip smoker. Theplace where the pipe is put is loosed and itstains in dark. Look at the picture:


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Look at the staining of dentine, because

dentine absorbs pigment easily sodiscoloration of dentine occurs.Sometimes its occupational abrasion like hairgrip holding or any other foreign materialinserted in the mouth, all of these induceabrasion.

SLIDE#16..Erosion.

Erosion is loss of tooth structure due tochemical process other than bacterial action,the acid here is not produced by bacteria ,theacid comes from our food like Pepsi whichwill be in contact with labial surfaces oftooth, so we will see shallow and broad lossof tooth structure due to acidic drink

.Remember its shallow and broad not sharpwedge shape with sharp angles found on thelabial surfaces of max.teeth and palatalsurfaces of the posterior teeth because afterwe drink acidic material it will go downthrough the whole mouth not only theanterior regions. Look at this picture the DR

said it's difficult to tell if its erosion orattrition or even abrasion because we haveporcelain bridges where there is no tooth to

tooth contact, so forget about this picture.


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Now look at the picture below here at thelabial or buccal surfaces there is shallow

broad loss of tooth structure

Some people work at area with acidic

atmosphere so the upper and lower teeth willbe eroded.

Pathologic causes of erosion like, continuousvomiting and you know that it's full of acidssince it comes from the stomach, and it willaffect the palatal aspect of the teeth,

especially the upper anterior teeth.Conditions with frequence vomiting.

*Pregnancy*Alcohol drinking

*Anorexia nervosa and bulimia nervosaBulimia nervosa: people eat a lot, but afterthey finish eating they realize that they ate alot then they starts inducing vomiting this isnot a normal case because they can't control

their apatite.Anorexia nervosa: people who think they arefat but they are not they look at the mirrorthey see themselves very fat so they startinduce vomiting, again this is not normal .the

Shallow broadloss of tooth


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net result is palatal erosion of the teethbecause of recurrent vomiting ,andsecondary dentin will form to protect thepulp and dentinal tubules may be closed.

SLIDE#19Resorption.

Let's talk about root loss: the root has dentinand cementum, in resorption we have wehave something related to physiologic andpathologic.

Physiologic root resorption: you can't see itradio graphically, it's a continuous process.sometimes the resorption happened on the

osteoclast and the then deposition, but youdont see it radio graphically .ones you seeresorption radio graphically its pathologic

)Now the resorption may beexternal or internal(.Why there is external root resorption?

Answer: most likely due to inflammation, whenthere is bacteria reaching the pulp thebacterial toxins and products, mediator ofinflammation like chemokine and cytokinewill induce osteoclast resorption,mechanicalpressure, like crowding, cysts and tumor,orthodontic treatment all these may induceresorption. Sometimes heavy occlusal load oncertain tooth may induce resorption or

hypercementosis. Sometimes resorption isidiopathic you can't find the causes.Now you should know the location of each typeof resorption,the inflammation occasionallyon the periapical regions.


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Other causes of resorption is due to luxationand reimplantation, sometimes the toothgoes out of its socket due to trauma, so weimmediately brush it and return it to itslocation and this is called reimplantation, itcould cause progressive resorption of the

root and replace it by bone .when wereimplant the tooth acute inflammationhappens, then resorption, and deposition.

One of the students asked "what about thenerve and blood vessels what will happen tothem"

Answer: the DR said the tooth will be non vital

because we do RCT at least 4 weeks aftertrauma to avoid necrotic products of the pulpto go out and induce chronic inflammation.The Dr was not sure if implantation causesankylosis or not so she asked one of thestudents to search about this and here aresome information about it I hope it ishelpfulof course this will not be enoughwe still need our colleague research because

this is one of the trails.

A study was designed to determine if avulsed permanent incisors which have been kept dry for a periodand then immersed in an isotonic solution prior to implantation have an increased healing rate(performless ankylosis) . After extraction of the teeth, the teeth of a treatment class were stored either dry, wet,Or first dry and then wet One week after reimplantation, the percentage of sites with ankylosisincreased with increased dry time. Subsequent wet storage in Hanks solution (isotonic solution mimicsthe oral environment) decreased the frequency of ankylosis. Storage in just a wet environmentFor up to 60 minutes resulted in a negligible Percentage of ankylosis. It was concluded that avulsedTeeth which have been kept dry for 15 minutes or longer should be conditioned in an isotonic solutionfor about 30 minutes prior to reimplantation. When the dry time exceeds 30 minutes, there is a greatlyincreased risk of ankylosis after reimplantation. *

So we conclude that ankylosis occurs but in different percentage depending on the drying time of the toothafter extraction.Reference (PEDIATRIDCE NTISTRY/ The American academy Pedodontics/ Vol 4. , No. 4/Ankylosis of experimentally reimplanted teeth

Related to extra-alveolar period and storage environmentLars Matsson, DDS, Odont Dr Jens Andreasen, DDS

Miomir Cvek, DDS, Odont Dr Lars Granath, DDS, Odont Dr)


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Now we talked about orthotreatment as

mechanical cause of pressure on the teeth,sometimes there is excessive force on thetooth so its location of resorption is apicallywhen the cause is gone its reversible,hypercementosis occurs and the toothbecome normal , so any cause of pressuremay induce resorption.

Look at this tooth and predict the cause?

Answer: it may be trauma which cut theblood supply and then there will be necrosisof the pulp which will induce inflammationeven if there is no bacteria, so it may betrauma, orthotreatment, may be idiopathic,

one of the students said that it could bedentine dysplasia and the DR answered that,if the pulp is obliterated we could think aboutit but in this case its not. Now for idiopathic


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causes the best location is the cervicalregion, now ankylosis may result.SLIDE#25.Internal root resorptionThe pathologic resorption may start frompulpal surfaces, there is necrotic pulp, and

then the pulpal inflammation starts resorpingthe inside of the pulp chamber and the insideof the canal, so the internal resorption startsfrom the inside , idiopathic type may alsooccurs. Look at the tooth below the pinkappearance of this tooth, because there is adecrease in thickness of dentine due to

internal resorption.

So you can see the shadow of the pulpthrough the reduced dentine thickness.SLIDE#26.External resorption of the crown..External resorption of the crown it self israre, if the tooth is impacted and there is apressure in the surrounding teeth there maybe resorption and even ankylosis may occur

even its on the crown itself may be attachedto the bone.

Discoloration of the teethSLIDE#2


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The changes in the color of the tooth may befrom outside or due to the structure it selflike in dentinogenesis imperfecta andamelogenesis imperfecta.Lets talk about extrinsic staining in generalwhere there is adsorption of the pigment on

the surface of the tooth, like coffee, tea foodpigments, the other type is chromogenicbacteria, which is a kind of bacteria whichproduces black pigment seen commonly inchildren teeth on cervical margin , anotherthing is the diffusion of pigment insidedentin either after tooth formation or during

tooth formation.We talked about amelogenisis anddentenogenisis in details in the previouslectures; we talked about opalescentappearance of teeth due to abnormality indentine.SLIDE#6Diffusion of pigment after toothformation.Suppose we have exposed dentine, look atthis picture..

Notice the color of dentine, because we haveexposed dentine then the pigment diffuseinside dentine, and this is called diffusion of


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pigment after tooth formation. For theperson in the picture does the he haveformed or forming dentine? It's formed andthe tooth has yellow appearance due todiffusion of pigment after tooth formation.Another reason for diffusion of pigment after

root formation is pulp necrosis; its somethingcoming from the inside, the result pulpnecrosis will diffuse through dentine .andthis will changes the color of the tooth, andthis is a common case in the clinic, the toothis brown in color we take a radiograph, andwe will find a periapical region and we will

find that the pulp is necrotic and this is thepigment that diffuse in the coronal dentine,another case is patient with amalgamfilling ,so people prefer to put compositerather than amalgam fillings. all of these arediscoloration after tooth formation.

(Discoloration of tooth dueto amalgam filling)One of the student asked why people withRCT will have blue color around the tooth.Answer: the reason is that the pulp chamberis no totally removed during RCT, Ideally youshould remove all the pulp chamber, if thedentist only opened the axis of the root canaland didnt remove the pulp chamber hewould leave mesial ,distal pulp this pulp


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which is left on either side of the axis willdegrade and degenerate and the pigment willdiffuse in dentine.Look at this picture.

The color may be due to diffusion of pigmentthrough dentine but mostly it's due tointernal root resorption.SLIDE#8Incorporation of pigment into dental hardtissues during their formation..Now if something happened during

development of teeth, pigment may diffusethrough dentine, due to disease likecongenital porphyria where there is error inporphyrin metabolism which gives us redcolor that deposits on any tissue in the body,like bone, tooth structure and even in theurine. So this deposition will change the color

of the teeth. Another thing is neonataljaundice, some times neonates have jaundice(hyperbilirubinamia) this will depositsbilirubin every where in the body includingthe brain, another type jaundice is due tohemolytic anemia if this happened duringtooth development the pigment will deposit

inside dentine. Deposition of pigment may bein enamel or dentine but it's much more indentine because it contains more protein andmore organic substances than enamel. Lookat this picture you can notice that hemolyticanemia affects the entire tooth which means


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it took place for along period of time duringdevelopment of all these teeth.

SLIDE#10Congenital porphyria

Congenital porphyria again there is an errorin porphyrin metabolism, so there is redpigment, even in the body, urine. so theteeth will appear red to brown, darklystained. Now why neonate jaundice is notgood, because of the deposition of bilirubinin the brain in high amount which mayinhibits the mental function of the individual,

so they replace the whole blood.SLIDE#13..Tetracycline pigmentation..Its an anti biotic given for several reasons,incorporates within dentine so we shouldtake care when we give it to our children.children below 9 should not be given this

drug, because it will diffuse in dentine,appearing in horizontal bands or lines ofyellow to brown which will darken with timeand also pregnant ladies should not take it,because it will cross the placenta and goes


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to deciduous dentition of the neonate, thebands will fluoresce yellow under UV. Thestaining depends on the dose as we increasethe dose the stain will become more intense.And it also depends on age according to thelevel at which the tooth is being formed.

Look at the bands in the picturebelow

Thats itSorry for any mistake ..

**

**Done by: Bayan mrayan

Fluorescent bands

tetracycline alongincremental lines o

lecture 4 ,other disorders of teeth (script)

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