Christine  Hawke  Sydney  Pet  Dentistry  

Small  Dog,  Big  Smile  

How  to  make  sure  your  little  dog  has  a  happy,  healthy  mouth  

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INTRODUCTION  

 

Hello  and  thanks  for  downloading  my  book,  ‘Small  Dog,  Big  Smile  –  How  to  make  sure  your  little   dog   has   a   happy,   healthy   mouth’.   Small   dogs   are   gorgeous,   and   deservedly   very  popular  throughout  the  world.  Centuries  of  careful  and  selective  breeding  has  provided  us  with   a   huge   range   of   small   breeds   to   choose   from,   each   with   their   own   specific  characteristics  and  charm.    

 

While  good  things  certainly  come  in  small  packages,  one  of  the  drawbacks  of  their  small  size  is  that  many  of  these  dogs  suffer  silently  from  serious  dental  issues.  While  all  dog  breeds  are  susceptible   to   ‘teething   problems’,   periodontal   infection   and   orthodontic   disorders,   dogs  with  small  mouths  have  the  added   issue  of  overcrowded  teeth  to  contend  with.  Similar   to  their  larger  ancestors,  they  have  to  find  space  for  42  teeth,  which  is  sometimes  no  easy  feat.  As  a  result,  things  don’t  always  go  according  to  plan….  

 

My  name  is  Christine  Hawke,  and  I  am  a  veterinarian  with  almost  20  years  experience  in  small  animal  practice.  After  many  years   in  general  practice,   I  developed  a  passion  for  all   things   dental,   and   have   been   running   a   small   animal  dentistry-­‐only   practice   in   Sydney   since   2007.   I   am   a  Member   of   the   Australian   and   New   Zealand   College   of  Veterinary   Scientists   in   the   field   of   Veterinary   Dentistry  (this   can  only  be  attained   through  examination),   and   the  American   Veterinary   Dental   Society.   I   am   currently   the  President  of  the  Australian  Veterinary  Dental  Society,  and  teach   veterinary   dentistry   to   vet   students   (at   The  University  of  Sydney),  vets  and  nurses  across  Australia.    

 

Imagine  having  a  sore  mouth  and  not  being  able  to  tell  anyone!  

One  of  the  biggest  misconceptions  is  that  dental  problems  don’t  need  the  same  treatment  in  animals  as  they  do  in  humans.  Nothing  could  be  further  from  the  truth!  Dogs’  teeth  have  the  same  type  of  nerve  supply  in  their  teeth  as  we  do,  so  anything  that  hurts  us  will  hurt  them  as  well.  All  dogs,  whether  they  are  performance  dogs  or  pets,  deserve  to  have  a  healthy,  pain-­‐free  mouth.  

Oral   and   dental   issues   frequently   go   undiagnosed   in   dogs,   partly   because   the   disease   is  hidden  deep  inside  the  mouth,  and  partly  because  dogs  are  so  adept  at  hiding  any  signs  of  pain.  As  a  pack  animal,  they  don’t  want  to  let  the  rest  of  the  pack  (including  us!)  know  they  have   a   problem,   as   anything   that   limits   their   usefulness   to   the   pack  may   be   grounds   for  exclusion.  This  is  a  survival  instinct.  

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Dogs   will   suffer   in   silence   for   as   long   as   they   can,   and   they   only   stop   eating   when   they  cannot  bear  the  pain  any  longer.  

How  to  get  the  most  out  of  this  book  

This  book  has  been  written  to  help  you  understand  how  oral  and  dental  problems  develop  in  small  dogs,  what  the  implications  of  these  issues  are,  and  what  options  are  available  to  you  and   your   dog   to   achieve   the   best   outcomes   in   terms   of   overall   health,   comfort   and,   if  applicable,  performance.  

If  you  would  like  to  speak  to  me  for  advice  on  your  dog,  please  feel  very  welcome  to  call  me  on  0408  782  611.  Alternatively,  you  can  email  me  on  christine@sydneypetdentistry.com.au  

 

 

TABLE  OF  CONTENTS  

 

WHAT’S  THE  BIG  DEAL  ABOUT  SMALL  DOGS?   4  

PERIODONTAL  DISEASE  AND  JAW  FRACTURE   5  

UNERUPTED  TEETH   10  

UNDERERUPTED  TEETH  AND  PERICORONITIS   13  

TRAUMATIC  BITE  DEVELOPMENT  (MALOCCLUSION)   14  

PERSISTENT  DECIDUOUS  (BABY)  TEETH   16  

SO  HOW  DO  I  MAKE  SURE  MY  SMALL  DOG  HAS  A  BIG  SMILE?   19  

 

WHAT’S  THE  BIG  DEAL  ABOUT  SMALL  DOGS?  

 

Small  breed  dogs  have  been  selected  and  bred  over  many  generations  to  have  small  heads  and  jaws,  but  not  necessarily  small  teeth.     In  fact,  tooth  size  tends  to  be  more  resistant  to  breeding  selection   than  head  or   jaw  size.  While  a  Chihuahua  or  Pomeranian  obviously  has  smaller   teeth   than   a   Mastiff   or   a   Greyhound,   their   teeth   are   relatively   huge   when   the  differences   in   jaw   size   are   taken   into   account.   Therefore   they   are   more   prone   to  overcrowding.  

 

Sometimes  small   jaws  and  overcrowded  teeth  may   lead  to   issues  affecting  performance   in  the  show  ring.  The  bite  may  become  ‘bad’  with  one  or  more  teeth  out  of  alignment,  or  even  a   major   malocclusion   such   as   reverse   scissor   bite   (or   rostral   crossbite).   However,   the  consequences   of   small   jaws   and   crowded   teeth   are   not   always   purely   cosmetic,   and   can  have  significant  health  implications.    

 

 

 

PERIODONTAL  DISEASE  AND  JAW  FRACTURE  

 

Dogs   with   crowded   teeth   are   much   more   prone   to   periodontal   disease   than   those   with  ‘roomier’  mouths.  Periodontal  disease  is  an  inflammation  of  the  gingiva  (gums)  and  deeper  supporting   structures   of   the   tooth   (ligaments   and   bony   socket),   caused   by   the   buildup   of  plaque  bacteria  on  and  around  the  tooth.    

Natural   tooth   cleaning  mechanisms   that   assist   in   controlling   plaque   accumulation   include  chewing   (mechanical   removal   of   plaque   deposits   by   abrasion)   and   saliva   flow   (flushing  action  and  antibacterial  components,   including  immune  compounds  and  enzymes).  Both  of  these  processes  are  far  less  effective  if  teeth  are  crowded  together,  rotated  or  overlapping.  Even  our   best   human  efforts   to   keep  overcrowded   teeth   clean,   such   as   tooth-­‐brushing  or  use  of  antiseptic  rinses  or  gels,  can  be  rendered  ineffective  as  many  of  the  tooth  surfaces  are  just   too  difficult   to   access.   In   humans,   flossing  between   teeth   can  help,   but   few  dogs  will  tolerate  this!!  

 

 

Overcrowded,   rotated   teeth  with   advanced   periodontal  disease   in   a   two   year   old  Japanese   Chin   (left).   Despite  the   young   age   of   the   dog,   the  canine   and   all   four   premolars  required  extraction.  

 

 

Left   undisturbed,   these   bacteria   multiply   and   spread   below   the   gum   margin,   causing  gingivitis   (gum   inflammation   and   bleeding)   and   eventually   destroying   the   jawbone   itself.  Bacterial   spread   into   the   underlying   bone   is   further   enhanced   when   teeth   are   crowded  together,  as  the  lack  of  space  prevents  the  gum  from  forming  a  seal  around  each  tooth.  With  no  effective  barrier  between  overcrowded  teeth,  irreversible  damage  to  the  deep  structures  of  the  jaw  rapidly  follows.    

 

Crowded   teeth   without   a  gingival   seal   between   the  teeth   (arrow).   Bacteria   can  easily   invade   the   jawbone  between  these  teeth  as  there  is  no  effective  barrier.  

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While  early   loss  of  teeth  is  the  most  common  final  outcome  of  severe  periodontal  disease,  far   more   serious   issues   can   also   occur,   including   infection   of   the   sinuses,   oral   fistulas  penetrating   into   the   nasal   cavity,   and   even   broken   jaws!   The   lower   jaw   is   particularly  susceptible  to  fracture  in  small  breed  dogs,  as  it  is  relatively  small  and  the  tooth  roots  often  extend  right  through  almost  the  entire  thickness  of  the  bone.    

Dental  xray  of  a  2.5  kg  Maltese  terrier   X   (left).     Severe   bone  loss   is   occurring   around   all  teeth,   with   the   overcrowded    tooth   crowns   providing   areas  for   bacteria   to   collect   and  head   down   into   the   deeper  structures.   The  mesial   root   of  this   ‘oversized’   lower  carnassial   tooth   (the   left   root  of   the   biggest   tooth)   extends  right   down   to   within   about   a  millimetre   of   the   lower   edge  of   the   jaw.   The   root   has  developed  with  a  big  bend  in  it  as  it  ran  out  of  space  to  grow.  

 

 

 

 

Overcrowded   teeth   in   a   6kg   terrier   (right,  top  picture).    Plaque  and  tartar  can  build  up  in  between  these  teeth  (arrow),  which  have  no   gum   barrier   between   them   to   prevent  bacteria  from  entering  the  jawbone.    

A  dental  xray  (right,  bottom  picture)  shows  the  extent  of   the  bone   loss  between   these  two  overcrowded  teeth.  A  probe  confirmed  that  this  pocket  was  1cm  deep  –  a  lot  for  a  small  dog,  and  on   track   for  a   fractured   jaw  in   left   untreated.   The   tooth   was   extracted  to  prevent   further  bone   loss   and  allow   the  infection  to  heal.  

 

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Jaw   fracture   in   a   12   year   old  Australian   terrier   with   severe  periodontal   disease.   Chronic  infection   weakened   the   bone  

to  the  point  where  it  snapped  when   she   bumped   her   face  coming  down  the  stairs.    

 

 

 

 

 

 

 

Finally,  bacteria  can  easily  gain  access  to  the  bloodstream  when  the  gingival  attachment   is  weak  or  damaged,  spreading  to  the  rest  of  the  body,  including  the  liver,  heart  and  kidneys.  In   humans   there   is   a   well-­‐documented   association   between   periodontal   disease   and  illnesses   such   as   heart   attack,   stroke   and  premature  birth   in   humans.   In   dogs,   heart,   liver  and  kidney  pathology  has  been  reported  to  be  associated  with  periodontal  disease.    

 

What  can  we  do  about  the  risk  of  periodontal  disease  in  small  dogs?  

All   dogs,   large   or   small,   should   have   a   good   oral   hygiene   program   to   control   plaque   and  tartar   buildup.   This   should   be   started   from   a   young   age,   and   can   include   varying  combinations  of  tooth  brushing  (by  far  the  most  effective  method  –  this  is  why  OUR  dentists  recommend  it!),  chewing  using  effective  dental  diets  and  chews,  and  chemical  disinfectants  designed  for  use  in  pets.  For  more  information,  including  tips  for  introducing  tooth  brushing,  check  out  www.sydneypetdentistry.com.au.  

Damage  caused  by  chronic  periodontal  disease  can  severely  weaken  the  jaw    -­‐  enough  for  it   to   snap  with   only  minor  pressure   (such   as  catching  a   ball,  or  bumping   into   a  wall   or  doorway).    

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For  dogs  with  overcrowded  teeth,  early  intervention  can  reduce  the  risks  and  make  it  easier  for  the  teeth  to  be  kept  in  good  condition.  The  best  treatment  plan  for  each  individual  dog  depends  on  which  teeth  are  involved,  and  what  the  plans  are  for  the  dog  (eg  performance  vs  pet).   Orthodontic   movement   and   and   selective   extraction   are   a   couple   of   options   to  consider.  

Orthodontic   treatment   may   help   move   the   teeth   into   a   better   position,   and  may   be   the  preferred  option  for  dogs  that  need  all  of  their  teeth  eg  for  working  or  showing.  Remember  that  orthodontics  can  be  complicated,  and  may  not  actually  create  more  space  if  crowding  is  severe.   Each   tooth   also   has   a   large   root   hidden   below   the   gum   level,   so   the   degree   of  crowding   may   be   even   worse   down   there   than   it   appears   on   the   surface,   limiting  orthodontic  options.  Orthodontic  movement  of  teeth  also  has  serious  ethical  considerations  for  showing  or  breeding  dogs,  so  it  is  strongly  advised  that  you  discuss  this  with  a  vet  who  is  well  informed  of  the  restrictions  on,  and  ramifications  of,  this  treatment  method.  For  further  advice,  you  can  also  call  me  on  0408  782  611.  

Selective  extraction  of  teeth  can  reduce  the  risk  of  oral  infection,  and  increase  the  likelihood  that  major  teeth  will  remain  healthy  and  functional  for  the  many  years  our  modern  pets  now  live.   The   decision   to   remove   one   or  more   teeth,   and  which   teeth   to   remove,   is   based   on  several  factors,  including  the:  

• position  of  the  tooth  (eg  a  tooth  that   is  severely  out  of  alignment  vs  one  that   is   in  the  correct  position)  

• importance  of  each  tooth  (eg  a  large  carnassial  or  canine  vs  a  small  premolar)  • health  status  of  each  tooth  (eg  a  tooth  which  is  damaged  or  already  has  significant  

periodontal  disease  vs  a  healthy  tooth)    

 

 

Crowding   between   the   large  first   molar   (right)   and   the  smaller   second  molar   (left)   has  resulted   in   severe   periodontal  disease   affecting   both   teeth.  Had   the   smaller   tooth   been  removed   earlier,   the   larger  tooth   may   have   been   kept  healthy  and  saved.      

 

The   thought   of   extracting   teeth,   particularly   healthy   teeth,   to   prevent   future   extractions  may  sound  counterintuitive.  However,   in  the   long  run,  selective  extractions  can  save  more  teeth   than   not   doing   anything,   as   the   remaining   teeth   are   less   prone   to   infection   and  disease.   For   example,   it   can   be   better   to   lose   one   small   lower   incisor   and   save   the  neighbouring  canine,  than  to  lose  both  down  the  track!  

 

Crowded  teeth

Severe  bone  loss

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Of  course,  extractions  are  not  always  an  option,  especially  in  show  animals.  The  alternative  is   meticulous   plaque   control,   using   home   hygiene   methods   such   as   toothbrushing,  appropriate   chewing   and   oral   disinfectants.   Regular   scaling   and   polishing   under   general  anaesthesia  to  remove  plaque  and  calculus  that  can’t  be  controlled  by  these  methods  is  also  required.  

 

 

UNERUPTED  TEETH  

 

Unerupted   teeth   can   be   a   serious   issue!   Pups  may   have  missing   deciduous   (baby)   teeth,  permanent  (adult)  teeth,  or  both.  When  a  tooth  is  missing  and  has  never  been  present,  the  possibilities  are:  

1) There   is   no   tooth  present   at   all   (congenitally  missing)   –   this  may  be   a   genetic  trait  in  some  breeds,  including  many  of  the  smaller  breeds  

2) There  is  a  tooth  present  but  it  is  having  trouble  erupting  –overcrowded  mouths  are   especially   predisposed   to   as   there   isn’t   much   room   for   error   and  neighbouring  teeth  can  block  the  eruption  pathway    

A  congenitally  missing  deciduous  tooth  almost  always  means  that  there  will  also  be  no  adult  tooth   in   that   position   (this   is   because   the   adult   tooth   buds   develop   from   the   deciduous  tooth  buds  during  gestation)1.  Not  all  congenitally  missing  teeth  are  genetic  problems  -­‐  just  like  humans,  sometimes  these  things  ‘just  happen’  during  development.  However,   in  many  cases  genetics  do  play  a  role,  and  so  caution  needs  to  be  exerted  when  planning  breeding  that   involves  an  affected  dog  or   its   close   relatives.  Dental   xrays  can  be  used   to  determine  the  presence  of  adult  tooth  buds  prior  to  eruption,  from  8-­‐12  weeks  of  age.  

 

 

Xray   revealing   a   congenitally  missing   permanent   second  premolar  tooth  in  a  six  month  old  pup.  The  deciduous   tooth  is  still  in  position,  with  no  sign  of   the   permanent   tooth  underneath  it.    

 

 

 

If   the   tooth   is  present   but   unerupted,   early   detection   is   critical.   Commonly,   something   is  obstructing   its   eruption,   such   as   thickened   gum   tissue,   a   narrow   bony   socket   opening,   or  another   tooth   blocking   the   pathway   (commonly   a   persistent   deciduous   tooth,   or   a  neighbouring   adult   tooth).   In   other   cases   the   tooth   may   be   deformed   or   in   the   wrong  position,  and  therefore  unable  to  erupt.  

                                                                                                                         

1  The  exceptions  here  are  all  molar  teeth,  and  the  first  premolar  teeth,  which  do  not  have  a  deciduous  predecessor  in  dogs  

Deciduous  tooth

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An   eight   month   old  Pomeranian   with  persistent   deciduous  teeth   sitting   over   a  bony   swelling   in   the  upper   jaw,   which   was  suspected   to   be   an  unerupted   permanent  tooth.    

 

 

Xray   of   the   same   dog   showing  an  unerupted  permanent  upper  fourth   premolar   (carnassial)  tooth   (red   arrow),   which  became   impacted   due   to  persistent   deciduous   upper  third   and   fourth   premolars  (blue  arrows).    

 

 

 

 

What  can  we  do  about  unerupted  teeth?  

If   a   tooth   is  missing,   it   should   be   investigated  with   dental   xrays   as   soon   as   it   is   noted   to  determine  if  there  is  a  tooth  hidden  below  the  gum.  If  the  tooth  is  congenitally  missing,  no  intervention   is   required.   In   fact,  depending  on  which   tooth   is  missing,   this  may  be  a  good  thing  for  the  dog  as  far  as  health  and  function  goes,  if  it  reduces  the  very  overcrowding  that  we  are  concerned  about.    

If  an  unerupted  tooth  is  detected  early,  before  the  eruption  process  has  finished,  it  may  be  able  complete  its  eruption  once  the  cause  of  impaction  is  surgically  corrected  (eg  removing  the   tooth,   bone   or   gum   tissue   that   is   impeding   eruption).   Sadly,   in   other   cases,   normal  eruption  may  not  be  possible,  even  with  advanced  surgery.  This  is  especially  true  if  the  tooth  is  deformed,  poorly  positioned  or  orientated,  or  the  eruption  process  has  finished  (closure  of  the  root  will  mean  further  eruption  is  not  possible).    

Persistent  baby  teeth

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This   seven   year   old   dog   had   a   missing   lower   right   canine   tooth   that   had   never   erupted  (above).   Xrays   confirmed   that   the   tooth   was   indeed   present,   but   had   become   impacted  behind  a  lower  incisor,  and  was  therefore  unable  to  erupt  (below  left).  A  huge  dentigerous  cyst   had   formed   around   the   tooth,   destroying   the   jaw   bone.   Despite   the   high   risk   of   jaw  fracture,   it  was  successfully  surgically  extracted  and  the  cyst   tissue  removed   (below  right).  This   post-­‐surgical   xray   shows   the   incredible   amount   of   destruction   a   dentigerous   cyst   can  cause.  Fortunately,  while  the  remaining  bone  was  only  about  half  a  millimetre  thick,  the  jaw  healed  uneventfully.    

 

Unerupted   teeth   should   be   surgically   extracted   as   they   can   form   a   dentigerous   cyst  around   themselves.   These   destructive   cysts   can   grow   to   occupy   most   of   the   jaw,  destroying   the   surrounding   bone   and   leading   to   facial   deformity,   tooth   loss,   jaw  weakness  and  even  jaw  fracture.  

 

UNDERERUPTED  TEETH  AND  PERICORONITIS  

 

The  crown  of  each  tooth  is  covered  in  a  hard  mineralised  material  called  enamel,  while  the  root   is   covered   in   cementum,   which   is   closer   in   composition   to   bone.   The   gum   normally  forms   its   seal   around   the   tooth   by   attaching   to   the   cementum   just   where   it   meets   the  enamel.  Gum  cannot  attach  to  enamel.  

If  a  tooth  only  partially  erupts,  part  of  the  crown  remains  submerged  below  gum  level.  This  creates  a  deep  pocket  around   the   crown  of   the   tooth  where   the  gum  cannot  attach   to   it.  This   pocket   traps   food,   debris,   plaque   bacteria   and   pus,   leading   to   severe   inflammation  around  the  tooth,  called  pericoronitis  (meaning  ‘inflammation  around  the  crown’).    

   

 

 

 

Undererupted  premolar  tooth  –  this  dog  is  only  six  months   old   and   already   has   significant  inflammation   (pericoronitis)   due   to   the   pocket  around  this  tooth  

 

 

If  a  partially  erupted  tooth  gets  stuck  underneath  the  crown  or  roots  of  an  adjacent  tooth  (due  to  overcrowding),  a  proper  gum  seal  cannot  form  between  the  two  teeth,  resulting  in  a  direct  pathway  for  bacteria  to  enter  the  jawbone.  The  resulting  periodontal  disease  can  then  result  in  premature  loss  of  both  the  undererupted  tooth  and  its  neighbour.    

 

What  can  we  do  about  undererupted  teeth  and  pericoronitis?  

Early  identification  of  undererupted  teeth  and  extraction  can  save  the  dog  from  the  pain  and  infection   that   they   cause.   It   can   also   save   any   adjacent,   more   important   teeth   from  irreversible   damage.   While   many   undererupted   teeth   go   undetected   (as   the   partially  exposed   crown   is   not   necessarily   flagged   as   abnormal   but   just   ‘small’),   having   your   dog’s  dentition  examined  by  someone  who  is  very  familiar  with  the  normal  shape  and  position  of  the   teeth   may   allow   early   detection.   Dental   xrays   can   then   be   taken   to   assess   what   is  happening  below  the  gumline,  so  that  a  treatment  plan  can  be  made.  

 

Pericoronitis   can   be   very   painful   -­‐   in   fact,   this   is   one   of   the   most   common   reasons  humans  have  their  wisdom  teeth  removed!  

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TRAUMATIC  BITE  DEVELOPMENT  (MALOCCLUSION)  

 

In  dog  breeds  that  are  of  similar  size  and  facial  profile  to  their  wild  ancestors  (mesocephalic  or  mesaticephalic  head-­‐type),  the  muzzle  length  provides  plenty  of  room  for  all  42  teeth  to  sit  in  a  scissor  bite  arrangement,  with  ‘smooth’  arcades  that  are  not  crowded.    

While   smaller   dogs   obviously   have   smaller   jaws,   this   has   not   always   been   bred   for   in   a  proportional  way.   The   brachycephalic   facial   profile   has   become  popular,   a   relatively   short  muzzle,  even  when  the  overall  smaller  size  of  the  dog  is  taken  into  account.  Several  smaller  breeds,   such   as   the   Pug,   Pekinese,   French   Bulldog,   Lhasa  Apso   and   Shih   Tzu,   are   typically  undershot  (short  upper  jaw  compared  with  lower  jaw),  which  can  lead  to  a  traumatic  bite  if  the   upper   incisors   are   striking   the   lower   incisors   or   the   soft   tissues   on   the   floor   of   the  mouth.  Even   in  small  breeds  where  a  scissor  bite   is  the  standard,  such  as  the  Pomeranian,  Cavalier  King  Charles  Spaniel,  Chihuahua,  and  Yorkshire  Terrier,  there  is  less  room  for  error  when  the  jaws  are  smaller  and  ‘tighter’,  so  traumatic  malocclusions  are  not  uncommon.  

 

 

Traumatic  malocclusion  -­‐   the   lower  canine  in   this   seven  month   old   pup   is   hitting   the  upper  gum  and   incisor  because   there   isn’t  enough   space   for   it   to   move   into   a  comfortable   position.   It   is   also   crowded  against  the  lower  incisor,  with  no  space  for  a  proper  gingival  seal  between  these  teeth.  

 

 

In  many  cases  an  undershot   jaw  or  other   jaw-­‐related  malocclusion  does  not  cause  the  dog  any  problems,  and  they  can  eat  without  trauma  or  pain  (otherwise  all  brachycephalic  dogs  would  be  in  trouble!).  However,  if  there  is  any  trauma  occurring,  it  needs  to  be  resolved  for  the  dog’s  health  and  welfare.  This  includes  both  damage  to  the  soft  tissues  (the  gums,  lips,  tongue)   and   the   teeth   (when   teeth   strike  or   rub  each  other,   painful   pulp   inflammation  or  excessive  wear  can  occur).      

 

 

Painful   ulcers   behind   the   lower   incisor   teeth  in   a   nine   month   old   dog   with   a   rostral  crossbite   (undershot   jaw).   These   are   caused  by  the  upper  incisors  digging  into  the  floor  of  the  mouth  every  time  she  closes  her  mouth.  

 

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What  can  we  do  about  malocclusions?  

If  there  is  a  traumatic  malocclusion,  the  best  type  of   intervention  will  depend  on  the  exact  nature   of   the   trauma.  Options  may   include  orthodontic  movement   of   teeth   into   a   better,  more   comfortable   position,   surgical   shortening   of   teeth   to   stop   them   from   hitting   other  tissues   or   teeth   (odontoplasty   or   vital   pulpotomy   and   capping),   or   selective   extraction   of  teeth.  

Taking  it  back  a  step,  it   is  also  important  to  take  jaw  length  issues  into  consideration  when  breeding   smaller   dogs.   While   pups   with   sweet,   short   faces   are   undeniably   cute   and  irresistible,  and  most   live  happy  and  comfortable   lives,  we  don’t  want   to  make  them  even  more  prone  to  dental  and  oral  disease  by  poor  breeding  choices.  Selecting  for  a  correct  bite  or  more  moderate   facial   profile  may   decrease   the   risk   of   future   puppies   being   born  with  uncomfortable  or  poorly  functioning  mouths.    

 

Always   remember   that   dogs   are   very   adept   at   hiding   oral   issues,   and   will   not   show  trouble  eating  or  signs  of  pain  unless  they  are  in  extreme  pain.  Therefore  it  is  important  to  have  your  dog’s  bite   thoroughly  assessed   to  ensure   that   the   jaw  arrangement   is  not  causing  discomfort  that  will  permanently  affect  their  quality  of  life.  

 

 

PERSISTENT  DECIDUOUS  (BABY)  TEETH  

 

While   not   actually   a   result   of   overcrowding,   persistent   baby   teeth   can   exacerbate   the  overcrowding   seen   in   small   dogs.   In   fact,   smaller   breeds   are   prone   to   problems   with  retained  deciduous  teeth,  which  is  ironic  as  there  is  very  little  room  in  their  mouths  to  start  with!  

Like  humans,  dogs  have  two  sets  of  teeth,  with  their  deciduous  teeth  being  replaced  by  the  permanent   (adult)   ones   during   the   first   six   months   of   life.   The   molar   teeth   and   the   first  premolars  do  not  actually  have  a  deciduous  predecessor;  so  all  deciduous  teeth  should  have  been  lost  by  six  months  of  age.  The  following  table  gives  an  indication  of  when  each  type  of  deciduous  tooth  erupts,  and  when  it  is  replaced  by  the  adult  version.  

 

  Deciduous  teeth  (weeks)   Permanent  teeth  (months)  Incisors   3  -­‐  4   3  -­‐  5  

Canines   3   4  -­‐  6  

Premolars   4  -­‐  12   4  -­‐  6  

Molars   -­‐   5  -­‐  7  

 

Sometimes  deciduous   teeth  are  not  shed  because   there   is  no  permanent   tooth  present   to  replace   it.  However,   if  a  permanent  tooth  does  erupt  without   loss  of   the  deciduous  tooth,  both  teeth  will  end  up  sharing  the  same  socket.    

 

Persistent  deciduous  teeth  are  bad  news  for  dogs  for  two  main  reasons:  

1. Similar  to  crowded  teeth,  if  there  are  two  teeth  in  one  socket,  the  surrounding  gum  cannot   form   a   proper   seal   between   these   teeth,   leaving   a   leaky   pathway   for   oral  bacteria  to  spread  straight  down  the  roots  of  the  teeth  into  the  jawbone.  Trapping  of   plaque,   food   and   debris   between   the   teeth   also   promotes   accelerated  periodontal  disease.  This  not  only  causes  discomfort  and  puts  the  adult  tooth  at  risk  of  early  loss,   it  allows  infection  to  enter  the  bloodstream  and  affect  the  rest  of  the  body.  

The  general  rule  of  thumb  is  that  there  should  never  be  two  teeth  in  the  same  socket.  

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Retained   deciduous   upper  canine   tooth   predisposes  the   adult   tooth   to  periodontal   disease,  Trapped   debris   and   plaque  can   already   be   seen   in   this  six  month  old  pup.  

 

 

 

 

 

2. If  the  deciduous  tooth  is  still  firmly  in  position  as  the  permanent  tooth  is  erupting,  it  will   force   this   tooth   into   an   abnormal   position.   In   small   dogs   with   little   space   to  spare  in  their  mouths,  this  can  cause  a  significant  traumatic  malocclusion.    

For  example,   the  permanent   lower   canines  normally  erupt  on   the   inside  of   the  deciduous  teeth.  If  they  are  forced  to  erupt  alongside  them,  they  can  end  up  in  an  abnormally  narrow  position.  This  often   results   in   these   teeth  striking   the   roof  of   the  mouth,   causing  pain  and  damage  many  times  a  day,  every  day.    

           Retained   lower   baby   canines    (green   arrows)   force   the  erupting   adult   canines   (red  arrows)   into   an   abnormally  narrow  position.                  

     

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Similarly,   the   permanent   upper   canines   normally   erupt   in   front   of   the   deciduous  ones,   so   pushing   them   further   forward   can   result   in   trauma   to   the   inside   of   the  upper   lip.   The   gap   in   front   of   the   upper   canine   (where   the   lower   canine   normally  slots  into)  is  also  closed  down,  forcing  the  lower  canine  inwards  to  strike  the  palate,  or  outwards  to  hit  the  lower  lip.    

 

 

 

Retained   upper   baby  canine   (green   arrow)  forcing   the   adult   canine  (red   arrow)   to   erupt   in   a  more   forward   (mesial)  position.   This   closes   the  gap   where   the   lower  canine   usually   sits,   and  may   force   it   into   a  traumatic  position.  

 

 

 

What  can  we  do  about  persistent  deciduous  canines?  

When   persistent   deciduous   teeth   are   associated   with   an   erupting   adult   tooth,   extraction  should  be  performed  as  soon  as  the  adult  tooth  is  coming  through,  especially  if  the  occlusion  is   tight   and   the   risk   of   developing   a   significant  malocclusion   is   high.   It   is   crucial   that   the  whole   tooth   is   removed,   including   the   root,   otherwise   it   will   still   block   the   correct  positioning  of  the  permanent  tooth,  and  can  act  as  a  source  of  infection.  Dental  xrays  prior  to   extraction   are   highly   recommended,   to   determine   whether   the   root   is   fully   intact,   or  whether  some  resorption  has  occurred.  Post-­‐extraction  xrays  will  then  confirm  that  no  root  fragments  have  been  left  behind.    

In  cases  where  the  deciduous  tooth  remains  and  no  adult  tooth  appears,  dental  xrays  should  be  performed  to  check  for  impacted  or  unerupted  adult  teeth.  Treatment  for  these  has  been  discussed  earlier  in  this  book.    

 

 

 

 

SO  HOW  DO  I  MAKE  SURE  MY  SMALL  DOG  HAS  A  BIG  SMILE?  

 

We  cannot  rely  on  dogs  to  tell  us  when  they  have  oral  pain.  It  is  up  to  us  to  be  vigilant  and  watch  for  signs  of  developing  problems.  Train  your  pup  to  allow  handling  and  examination  of  the   mouth   from   an   early   age.   Things   can   change   quickly   -­‐   check   their   teeth   and   bite  formation   frequently   as   they   grow.   Don’t   assume   that   older   dogs   have   no   problems   just  because  they  are  not  telling  you  about  it.    

Here  is  a  checklist  of  some  of  the  things  to  look  for:  

• Check  the  number  of  teeth  (any  missing  or  extra  teeth?)  • Check   the   position   of   the   teeth   (overcrowded,   rotated,   out   of   alignment,  

undererupted?)  • Check   the   jaw   length   and   the   way   the   teeth   fit   together   (is   there   any   abnormal  

contact  between  teeth  and  oral  tissues?)  • Check  for  redness,  swelling,  discharge  or  discoloured  deposits  on  the  teeth  • Does  the  breath  smell  bad?  • Note  any  problems  eating,  chewing  or  playing  

Seek  veterinary  care  as  soon  as  a  potential  problem  is  noticed  –  your  local  vet  is  the  place  to  start.   You   can   also   call   me   on   0408   782   611   or   email   me   anytime   on  christine@sydneypetdentistry.com.au  for  advice  or  assistance.  

 

 

Remember,   early   recognition   and  treatment   is   crucial   if  we  want   to  keep  your   dog   happy   and   healthy.   Many  issues   are   detectable   at   an   early   age.  The   sooner   we   treat   dental   problems,  the  more  chance  your  dog  has  of  having  a  healthy,  comfortable  mouth  for  life.