همواره یکی از مشکلات در مورد سگهایی که اطلاعات دقیقی از تاریخ تولد و یا سن آنها نداریم تعیین سن برای آنان می باشد. به خصوص در مورد توله سگها که از نظر واکسیناسیون و دیگر موارد درمانی باید مورد ارزیابی قرار گیرند. مقوله تعیین سن بر اساس دندان ها در دسترس ترین روشی است که ما را در تعیین حدودی سن سگها یاری می کند البته دقت این شیوه با افزایش سن سگها . کاهش پیدا می کند. البته باز لازم به ذکر است که دقت این روش تابع بسیاری موارد اختصاصی و محیطی می باشد که در ادامه مقاله در مورد آن توضیح داده شده است. تجربیات شخصی اینجانب به خوبی نشان داده که استفاده از این روش در تعیین سن بسیار مناسب می باشد .

البته احتیاط را هیچگاه فراموش نکنیم. زیرا که تعیین سن یک سگ بالغ  روتوایلر به قیمت از دست دادن دستمان اصلا ارزش ندارد.

یکی از راه های تعیین سن سگ استفاده از زمان رویش دندانهای شیری و دائمی و تغییرات ایجاد شده در آنها می باشد. معمولا بیشتر، دندانهای پیشین و تغییرات آنها ملاک تعیین سن بخصوص در سنین بالا برای سگها می باشد

سگها هم مانند بسیاری دیگر از حیوانات Diphydont هستند ، یعنی رشد دندانهایشان در دو مرحله صورت می گیرد ابتدا دندانهای شیری و سپس دندانهای دائمی.

در سگ دندانها به 4 نوع تقسیم بندی می شوند :

1. دندانهای پیش (Incisors)

2. دندانهای نیش (Canines)

3. دندانهای پیش آسیا (Pre Molars)

4. دندانهای آسیا (Molars)

 

سلامت عمومی، نوع تغذیه، جنس، نژاد و حتی فصلی که توله در آن متولد شده است برروی سرعت دندان درآوری و رشد آنها تاثیر دارد. در ماده ها نسبت به نرها دندانها سریعتر ظاهر می گردند، همینطور در توله های متولد تابستان دندان درآوری سریعتر از توله های متولد زمستان است.

فاکتورهای دیگر نیز تاثیر گذار هستند از جمله اینکه دندانهای نژادهای بزرگ سریعتر از نژادهای کوچک ظاهر می شود. گاهی در نژادهای کوچک دندانهای شیری تا زمان رشد دندانهای دائمی باقی می ماند و حتی برای اینکه جلوی رشد دندانهای دائمی را نگیرند باید توسط دامپزشک برداشته شوند.

توله سگ بون دندان متولد شده، در سه هفته اول هیچ دندانی ندارد و سپس در 3-4 هفتگی دندانهای شیری شروع به بیرون آمدن می کنند. ابتدا دندانهای نیش و بلافاصله دندانهای پیش که ابتدا در فک بالا و سپس فک پایین ظاهر می شوند. در حدود هفته 6  توله سگ در هر نیم آرواره، 3 دندان پیش، 1 دندان نیش و 3 دندان پیش آسیا دارد.

 بنابر این فرمول دندانی توله سگ به شرح زیر می باشد.

سنی که دندانهای دائمی جایگزین می گردند بر اساس نژاد متغیر است. در نژادهای بزرگ این جایگزینی زودتر صورت می پذیرد. جایگزینی دندانهای پیش در 5/3 تا 4 ماهگی شروع می شود و در 5 ماهگی کامل می شود اگرچه هنوز رشد دندانهای پیش کناری کامل نشده است.

 

معمولا زمان بیرون آمدن دندانها در 2 فک یکسان است. دندانهای سگ در 8  ماهگی کامل می شود. با رشد دندانهای دائمی، خونرسانی به دندانهای شیری کاهش یافته و پس از مدتی می افتند. در فک پایین دندانهای نیش دائمی در سمت داخل دندانهای نیش شیری در می آیند ما در فک بالا در جلوی دندانهای شیری در  می آیند. دندانهای پیش دائمی هم در پشت دندانهای پیش شیری در می آیند.

فرمول دندانهای دائمی در سگ به صورت زیر می باشد :

 

بعد از سن یکسالگی، طریقه جویدن غذا، سلامت دهان و دندان و ساختار دهانی تخمین سن سگ را مشکل می سازد. با اینحال به صورت حدودی بر طبق میزان سایش دندانها همچنان می توان سن سگ را تخمین زد.این روش در نژادهای بزرگ تا حدود 90% دقیق است اما سایش دندان در نژادهای کوچک و در سگهایی که فک آنها مقابل هم قرار نمی گیرد اغلب اشتباه می شود.

در 6 ماهگی سایش دندانهای پیش مرکزی فک پایین شروع شده و در 18 ماهگی کامل می گردد، از 5/1 سالگی تا 2 سالگی سایش دندانهای پیش میانی فک پایین شروع شده و در 5/2 سالگی کامل می شود.

بین 5/2 تا 3 سالگی سایش نوک دندانهای پیش مرکزی فک بالا شروع شده و در 5/3 سالگی کامل می گردد.

در 5/3 تا 4 سالگی سایش نوک دندانهای پیش میانی فک بالا شروع شده و در 5/4 سالگی کامل می گردد.

بین 5/4 تا 5 سالگی نوک دندانهای پیش کناری فک پایین شروع به سایش می کند و در 5/5 سالگی کامل می شود. حدودا در این سن نیش ها هم علائمی از سایش را نشان می دهند.

در 6 سالگی گوشه های اصلی دندانهای پیش کناری فک بالایی سائیده می شوند اما این دندانها به نظم بقیه دندانها سائیده نمی شوند، چون بخوبی و به طور کامل روی هم قرار نمی گیرند.

در 7 سالگی پیشهای مرکزی فک پایین یک حالت بادامی پیدا می کنند چون از سمت فوقانی به سمت ریشه شرسالگی دندانهای پیش مرکزی می افتند و بعد هم دندانهای پیش مرکزی بالایی . بقیه دندانهای پیش بین 12 تا 16 سالگی و دندانهای نیش بین 16 تا 20 سالگی می افتند.

 این الگوی تعیین سن در شرایطی در نظر گرفته شده است که دندانهای پیش در سایش کاملا روی هم قرار بگیرندو در واقع دندانهای پیش پایینی کمی عقبتر از دندانهای پیش بالایی قرار بگیرند. اگر فکها طوری باشند که دندانها با هم تماس پیدا نکنند یا پیشهای پایینی جلوتر قرار گیرند علائم سایش متفاوت خواهد بود. بنابراین سایش دندانها در نزادهایی مثل کوی(Coli) داشهوند(Dachshund) که فک پایینشان کوتاه است و در نژادهایی مثل باکسر (Boxer) ، بولداگ (Bulldog) و پکینز (Pekingese) که از نظر زنتیکی فک بالای کوتاهتری داند متفاوت خواهد بود.

تغییرات کلی دندانها در سگ ها به شرح جدول ذیل است:

این مقاله در پلی کلینیک دامپزشکی مرکز تربیت سگهای نظامی توسط بنده و دیگر همکارانم تهیه شده است و صرفا جهت ارتقا سطح علمی دانشجویان و علاقمندان این رشته برروی وبلاگ قرار گرفته است.

منابع:

تشخیص سن سگ به کمک دندانها - تالیف دکتر سرچاهی

Rottweiler Teeth - Dentition Diagrams - www.donnerbergrottweilers.com

How to Determine a Cat's or Dog's Age - www.ruralareavet.org

www.associatedcontent.com/article/1354491/how_to_determine_a_dogs_age_by_their.html

INTRODUCTION TO PUPPY TEETH:

Rottweiler puppies should have 28 temporary teeth that erupt at about three to four weeks of age. They will eventually have 42 permanent adult teeth that begin to emerge at about three to four months of age. As puppies, there are 14 upper and 14 lower puppy teeth.

There are four types of teeth with different functions:

Incisors: Used for cutting and nibbling food. Incisors are the front teeth situated directly in-between the canines. In adults and puppies, there are six upper and six lower. These are the front teeth and all six upper and all six lower are all in a row. The center two teeth are usually somewhat smaller and the incisor teeth get larger as you move out and away from the center.

Canine teeth: Used to hold and tear food. The canines are the large fangs. The lower canines lock in position in front of the upper canines. The canines are situated directly between the incisors and the premolars. In adults and puppies, there are exactly two upper and two lower canines. There is one on each side of the upper jaw and one on each side of the lower jaw.

Premolars: Used for cutting, holding, and shearing food. The premolars are positioned behind the canines and in front of the molars. Puppies do not have all of their premolars, but when the adult teeth come in, there will be 8 premolars on the top and 8 premolars on the bottom. Four premolars are on each side of the upper jaw and four premolars are on each side of the lower jaw in adults.

Molars: Used to grind food. The molars are positioned behind the premolars and are the last teeth in the back of the jaw. There are 4 molars on the top, two on each side, and 6 molars on the bottom, three on each side. Puppies don't have molars.

Diagram #1: Nine week old puppy,
showing a correct scissors bite.

In Diagram #1, you can see the incisors labeled "I", 1,2,& 3. Each tooth is identified by the upper or lower jaw and distinguished between left and right sides. The teeth labeled "C" are the canines. The large gaps between the teeth on even this nine week old puppy are normal and the gaps get larger as the puppy grows, prior to the adult teeth coming in. These puppy teeth are extremely tiny and it's not hard to tell the difference between them and adult teeth.



Diagram #2: Upper teeth of nine
week old puppy, showing 14 teeth.

Diagram #2 shows what you can expect to see in your own puppy's mouth. There are large gaps between the teeth at this point which should not be cause for alarm, yet. If you see gaps like this in an adult's mouth, you probably have missing teeth. In diagram #2, if you count the three back teeth you can see on each side, the Premolars, that's six, then add the two Canines, that's eight, and then add the six Incisors, that's a total of 14 teeth on the top.



Diagram #3: Lower teeth of nine week old puppy.

In Diagram #3, you see half of the lower jaw. It's nearly impossible to take a photo of the entire lower jaw showing all the lower teeth at the same time because the tongue and the lips naturally cover the teeth. The P1's and P2's are the hardest of all the teeth to show. Puppies don't have P1's, so there aren't any in Diagram #3. The P1's will be coming up in the gap you see in Diagram #3 in-between the teeth that are labeled "Canine" and "P2". In Diagram #3, if you count the three back teeth you can see, the Premolars, add the ones on the other side, that's six, add the two canines, that's eight, and finally add the six incisors, that's 14 on the bottom.



Diagram #4: Chart showing a full set of puppy teeth.

Puppies should lose a puppy tooth before the corresponding adult tooth emerges, but many times with Rottweilers, you'll see both the puppy tooth and the adult tooth side by side. This is especially true of the canines (commonly called the fangs). If a puppy tooth is still in place when an adult tooth begins to show, and it shows no signs of looseness, see your veterinarian to decide if the puppy tooth needs to be pulled so the dog's occlusion is not affected.



Diagram #5: Upper teeth of a youth dog
under 9 months old, showing extra teeth.

In Diagram #5, this photo actually shows newly erupted adult teeth still in transition, and one extra incisor tooth. The canines are marked with "C", and at this point the puppy canines are side by side with the adult canines which are still coming in. All of the large teeth in-between the canines are adult incisors. See how much larger the adult teeth are, and the gaps are closed. I'm pointing out the difference in size, because people get confused when they see an extra adult tooth. They think that it must be a puppy tooth that has not fallen out, but visually, you can see that the difference in size is enormous. Thus, any additional teeth in the mouth of this dog are extra adult teeth, and a decision must be made carefully and quickly as to whether or not the extra teeth should be pulled. Extra teeth left in the mouth, especially incisors, can throw a bite off and render the dog as pet quality and show disqualified.



Diagram #6: Lower teeth of a youth dog
under 9 months old, showing extra teeth.

In Diagram #6, this photo shows newly erupted adult teeth still in transition, and two extra adult incisor teeth on the bottom which have pushed the bottom incisors forward and out of alignment for a scissors bite. It is vitally important to keep a close eye on your puppy's teeth watching for abnormalities.





INTRODUCTION TO ADULT TEETH:

Rottweiler adults should have 42 permanent teeth in number, 20 upper and 22 lower. The teeth should be strong, correctly placed, and meeting in a scissors bite. The lower incisors should touch the inside of the upper incisors.

The adult canine teeth of Rottweilers are essential to be allowed to show and breed. The AKC Rottweiler Standard currently allows one missing tooth. The FCI Standard, which is what all the rest of the world besides America goes by, doesn't allow any missing teeth for the Rottweiler breed in order to be considered show and breeding quality. Don't make the mistake of walking into a show ring without counting your dog's teeth and checking your dog's bite first.

FCI Standard:
Jaws / Teeth:
Upper and lower jaw strong and broad. Strong complete dentition (42 teeth) with scissor bite, the upper incisors closely overlapping the lower incisors.
Faults:
Jaws: Narrow lower jaw.
Bite: Pincher bite.

Eliminating Faults:
Teeth:
Overshot or undershot bite, wry mouth; lack of one incisive tooth, one canine, one premolar and one molar.

AKC Standard:
Bite and Dentition--Teeth 42 in number (20 upper, 22 lower), strong, correctly placed, meeting in a scissors bite--lower incisors touching inside of upper incisors.
Serious Faults--Level bite; any missing tooth.

Disqualifications--Overshot, undershot (when incisors do not touch or mesh); wry mouth; two or more missing teeth.



Diagram #7: Shows a correct scissors bite on an adult Rottweiler.



Diagram #8: Chart showing the correct number
and placement of the upper and lower teeth.



Diagram #9: Showing the jaw closed and
how the teeth should mesh properly.



Diagram #10: A good view of the root system for the teeth.



Diagram #11: View of a moderate overbite,
with the canines in reverse order.

In Diagram #11, this drawing of a moderate overbite clearly shows that the lower canines will not mesh with the upper canines, and will in fact bore unnatural holes in the roof of the mouth of the dog. On overbites, the teeth find a place to go and do not interfere with the dog's ability to eat and certainly do not affect the health of the dog. Many veterinarians will tell people who have overbite puppies that they need to bring them in for surgical removal of the lower puppy canines because they are boring unnatural holes in the roof of the mouth. In all the time we've been breeding Rottweilers, overbites are the most common feature that occur rendering a puppy as pet quality. Of all of the overbite pet quality puppies we've produced, not one single one ever required any medical intervention or pulling of teeth because of the overbite and many times overbites do correct during the transition from puppy to adult.



Diagram #12: Shows a regular overbite,
a show disqualifying feature.

In Diagram #12, the drawing shows a regular overbite. On occasion, a regular overbite can and sometimes does correct into a scissors bite.

A puppy's bottom jaw will continue to grow until they are approximately nine months old, which means the bite is in transition until 9 to 11 months old. It should be noted that the top jaw is also in transition and growing during this period. The bite can go either way, from scissors to underbite or from scissors to overbite, or the most common would be from scissors to level bite.



Diagram #13: Shows a level bite.

In Diagram #13, the drawing shows a level bite which is breedable and showable and is not a disqualifying fault in the show ring, but it is a fault. A level bite is often heavily penalized by judges and is not desirable. Many older Rottweilers have level bites that show up later in life. Sometimes these bites are caused from excessive chewing or excessive tugging on the jaw.



Diagram #14: Shows an underbite,
a show disqualifying feature.

In Diagram #14, the drawing shows an underbite which is much less common than the overbite and level bite. In all the years we've been in Rottweilers, an underbite has never corrected to a scissors bite. While it is possible that it could happen, the odds against it are astronomical.

The only bite abnormality we don't currently have a drawing or photo of is the wry bite. A wry bite is when the teeth are crooked. Some of the teeth would be considered an overbite and some would be considered an underbite and some meet dead level. I've only seen a handful of wry bites, and some were caused by outside influences, and some were purely genetic.





If your dog's teeth become broken, a canine dentist can prepare a metal or porcelain crown. A broken tooth is a common problem, especially among outdoor dogs. Aggressive chewing on hard objects, such as rocks, cyclone fencing, cow hooves, bones or igloos, is a primary cause, and chewing on hard objects can also change a scissors bite to a bad bite and this would not be considered a genetic cause. Rottweilers are very aggressive chewers and their bites should be checked often and if you notice the teeth are shifting, you should remove any objects the dogs are chewing on. Rottweilers also can lose a tooth by pulling on cyclone fencing and crate doors and grating. Rottweilers have also been known to lose teeth from doing bite work and teeth have been pulled out of alignment from tug-of-war games.

Studies show that by age three, 80 percent of dogs exhibit signs of gum disease. Symptoms include yellow and brown build-up of tartar along the gumline, red inflamed gums and persistent bad breath. Small dog breeds are more likely to develop periodontal disease than large dogs because the teeth of small dogs are often too large for their mouths, according to veterinary dentistry experts. Plaque on dog's teeth are a concern because it can lead to heart disease. We highly recommend that you keep your dog's teeth clean by offering raw beef femur bones on a regular basis. We offer them regularly and let the dogs chew on them only long enough to clean their teeth, and then the bones are removed so that they don't chew all the enamel off their teeth. Sometimes only a half hour of chewing is sufficient to clean all the plaque off. Some dogs require a longer period of time.

We hope you found our article on the Rottweiler teeth and dentition helpful, educational and interesting. If you are having any special problems with your dog's teeth, and you have any photographs of your dog's teeth that you can send us that could be added to this page as another example of teeth and the problems we run into, we would appreciate you sending them to us so we can present them for educational purposes.