#Endodontic

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https://youtu.be/RAoebvrLnvk

الفيديو ده هيعلمك كل حاجة عن Access cavity preparation من البداية لغاية الاحتراف و كمان فيه كل tips and tricks اللي هتحتاجها ... و أحلي حاجة ان الشرح باللغة العربية

BURS FOR ACCESS CAVITY

 ** The access armamentarium should be simple, yet sufficiently versatile, to achieve the preparation goals. Every dentist who performs endodontic procedures has a preferred set of that are used for any given access procedure. Fortunately, only two, three, or four rotary cutting burs are typically required to create an optimal access cavity. Although it is normal for any given clinician to have a specific preference, generally most dentists can agree on a core set of burs. The following will provide a brief description of the Endo Access Kit (Dentsply Tulsa Dental Specialties; Tulsa, Oklahoma) that may be used to initiate, progressively open, and completely finish any access cavity within any tooth in the mouth .

• Diamond Round Bur: The #2 and #4 diamond round burs,

in conjunction with water, are utilized to brush-cut away

tooth-colored restoratives and to create a window through

materials such as porcelain . A #2 diamond

round bur is appropriately sized for bicuspid and anterior

teeth, whereas the #4 diamond round bur is generally the

right size for molar teeth. 

• Transmetal Bur: The transmetal bur is specifically

designed for cutting any type of metal . This bur

has a saw-tooth blade configuration, which provides efficiency

while reducing unwanted vibration, especially

important when entering pulpitis or so-called “hot teeth.”

• Carbide Round Burs: The #2 and #4 surgical length

carbide round burs provide extended reach and improved

vision during the entry into the pulp chamber .

Fortuitously, longer shank burs move the bulky head of

the handpiece further away from the occlusal table, giving

the clinician a line of sight along the shaft of the bur.

These burs are used to remove variously encountered

restorative materials and dentin, including the overlying

roof of the pulp chamber. Again, the #2 round bur is

appropriately sized for bicuspid and anterior teeth, whereas

the #4 round bur is sized best for molar teeth.

• Endo Z Bur: The Endo Z bur is a tapered and safe-ended

carbide bur . This bur is popular in that its noncutting

end can be safely placed directly on the pulpal floor without a

 risk of perforation. The Endo Z bur’s lateral

cutting edges are used to flare, flatten, and refine the

internal axial walls.

• Tapered Diamond Bur: A surgical length tapered diamond

bur may be utilized at high speeds to flare, flatten, and finish

the axial walls of the pulp chamber . A surgical

length tapered diamond bur is utilized to expand the

access preparation and to blend the axial walls so the

orifice(s) is just within this outline pattern. Strategically, a

surgical length, tapered, and end-cutting diamond bur can

be safely used at slow speeds of 500-750 rpm to safely,

selectively, and precisely sand away dentin, track along

grooves in search of hidden orifices, or when space is

available, to remove certain triangles of dentin.

• X-Gates: One X-Gates is comprised of four Gates Glidden

(GG) drills. Specifically, the heads of the GG 1-4 burs are

sequentially stacked on the active portion of a single

X-Gates to create a funnel-shaped form . The

X-Gates is rotated at a slow speed of 500-750 rpm and is used

 like a brush to cut dentin with its lateral surfaces or

belly on the outstroke. The X-Gates may be used for three

strategic purposes: (1) to initially open, flare, and smoothly

blend the canal orifice(s) to the axial walls, (2) to remove

internal triangles of dentin, and importantly, (3) to intentionally

relocate the coronal-most portion of a canal away

from furcal danger. Together, the X-Gates and surgical

length diamond bur are the burs of choice for finishing the

preparation and providing easy access to the underlying

root canal space.

Tips & Tricks of Access cavity preparation

 ** في المقال ده هنتكلم عن أهم Tips & Tricks اللي هتفيدنا جدا في خطوة Access Cavity preparation .. و هخلي المقال بالعربي عشان الكل يستفيد : 

1- #mouse_hole_effect 👇

مشكلة بتحصل مع دكاترة كتير وهيا ال mouse hole effect ودي ببساطه عبارة عن underextension لل access cavity فبيخلي مدخل ال orifice في ال axial wall وده غلط لان مفروض مدخل ال orifice يكون في في ال pulpal floor 👌

طب ليه المشكله دي مهم انك تتجنبها 🤔

لان لو خليت مدخل ال orifice في ال axial wall هتعمل stress على الفايل وهوا داخل ال canal واللي ممكن يعمل errors كتير بعد كده زى ledge او canal transportation او file fracture..الخ🧐🤐

حل مشكلة ال mouse hole effect دي ببساطه هتجيب safety-tip bur زي ال endo z bur وتوسع شويه ال axial wall ✌️🤓

2- وانت بتعمل access cavity بالذات في molars لازم تكون عارف ال entry point (initial outline) اللي هتبدا بيها عشان تخش في الpulp chamber مظبوط من غير اي مشاكل 🧐👇

ال entry point في ال molars بكل بساطه هيا عبارة عن نقطه وهمية موجودة في ال central groove في منتصف المسافه بين خطين وهميين:

الخطين دول لو في الupper molars هيبقوا خط بيصل بين ال cusp tips بتاعة ال mesiobuccal & mesiolingual cusps و خط تاني mesial لل oblique ridge 👌

الخطين دول لو فى ال lower molars هيبقوا خط بيصل بين ال cusp tips بتاعة mesiobuccal & mesiolingual cusps وخط تاني بيصل ال buccal &  lingual grooves

3 - https://youtu.be/cr9ohbFG-ww ( اعملوا نسخ للرابط و افتحوه )

    الفيديو ده شرح جميل جدا جدا جدا لبعض Tips & Tricks في Access cavity preparation ... لازم تسمعوه

4- #How_to_avoid_perforation 

فيه دكتور سأل عن ازاى تتجنب حدوث ال perforation 🤓

الحقيقة الموضوع كبير ويصعب شرحه فى post واحد لكن هنحاول نختصر الكلام في ال post ده👇👇

علشان نسهل الدنيا هنقسم ال perforations ل ٣ اقسام:

١- اول حاجه perforations اثناء ال access cavity 

٢- تانى حاجه perforations اثناء ال mechanical preparation of canals 

٣- تالت حاجه perforation during post preparation 

#النوع_الاول

ازاي تتجنب حدوث ال perforation اثناء ال access cavity preparation🤔

ال perforations اللي ممكن تحصل اثناء ال access حاجه من الاتنين ✌️

⏺ بيرفورشن في ال pulp chamber floor وده نتجنبه عن طريق 👇👇

*️⃣نعمل estimating لل depth of penetration من ال preoperative radiograph 

*️⃣مش كل الحالات تستني فيها حدوث ال drop in sensation 

*️⃣ لما تيجى توسع ال access cavity استخدم safe ended bur زي ال Endo Z bur علشان تتجنب انك تقطع في ال pulp chamber floor 

⏺ بيرفورشن فى lateral coronal wall وده نتجنبه عن طريق:👇

*️⃣ لو ال tooth كانت badly destructed ومش باين ليها ملامح اعمل ال access cavity قبل ما تركب ال rubber dam علشان تقدر تتخيل شكل ال tooth🤝

*️⃣ فى حالات ال tilted teeth او لو هتفتح access في tooth عليها crown خلي بالك جدا من ال bur orientation لانه لازم يكون مع ال long axis of tooth والا هتعمل perforation 👌

#النوع_التانى

ازاى تتجنب حدوث ال perforation اثناء ال mecanical preparation 👇

ال  perforations اللي ممكن تحصل اثناء ال preparation هما ٣ انواع:

⏺ strip perforation 

الكانال بيبقي ليها مثلا mesial &distal walls 

لو كان ال mesial wall ارفع من ال distal wall زي في اللور molars مثلا وانت محطتش ده في اعتبارك هيحصل معاك strip perforation في ال mesial wall

ده تقدر تتجنبه عن طريق

*️⃣استخدم precurved files 

*️⃣استخدم anticurvature filing ودي اتكلمنا عنها قبل كده

*️⃣ ما تستخدمش ال Gates Glidden تحت ال level of curvature 

⏺ apical perforation of curved canals 

وده بيحصل لو قابلك اى obstruction وانت شغال في الكانال زي ال ledge, calcification,  abrupt curvature..etc. وحاولت تعديها بانك تزود ال force عل الfile

⏺ perforation of apical foramen 

وده سببه حاجه من الاتنين:

- انك مظبطتش ال working length او اتغير منك اثناء الpreparation 

- انك تكون عملت apical transportation اللي هوا ال zipping وهنبقي نتكلم عن ال transportation في بوست منفصل

#النوع_التالت

اخر نوع من ال perforations وهوا اللى ممكن يحصل معاك وانت بتحط post فى ال canal وده بيحصل بسبب انك عملت wrong orientation لل gates glidden اثناء ال post preparation

5 - #Overextended_access_cavity 

فيه مشكلة بتقابل بعض الدكاترة وهما بيفتحوا access فى ال molars وهيا ان ال access بيوسع منهم جدا على ما بيلاقوا ال pulp chamber واللى بيضعف ال tooth جدا وبيزود فرصة ال fracture 🙄

سبب المشكلة دي ببساطه هو عدم تخيل ال position بتاع ال pulp chamber 🤔

ببساطه فى ال lower molars 👈 ال pulp chamber بتكون موجودة فى ال mesiobuccal portion of crown وبتشمل غالبا ال mesial 2 thirds و ال mesial outline اكبر من ال distal outline✌️

فى ال upper molars 👈 ال pulp chamber بتكون موجودة فى ال mesial half وبتكون mesial لل triangular ridge وال buccal outline بيكون اكبر من ال palatal outline✌️ 

6 - اول خطوة فى ال access cavity preparation واللي معظم الدكاترة مبياخدش باله منها لكنها مهمه جدا لانها عامل اساسى في انها تقلل فرصة ان يحصل perforation 🧐 

#Estimating_depth_of_access_cavity

لازم يبقي لك limit للdepth اللي هتخش بيه بال bur وده  متوقف عل حاجتين:

اول حاجة وهيا good quality preoperative x ray وهنا بنقيس المسافه بين الocclusal surface في الposterior او ال lingual surface فى ال anteriors وال roof of pulp chamber 

الحاجة التانيه وهيا ال average anatomical length بتاع كل ال teeth 

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✋✋ أتمني يكون المقال فادكم و السلام عليكم و رحمة الله 

Components of the pulp cavity

* As is known to every dentist or even dental student , The pulp cavity is divided into two main portions: the pulp chamber, located in (or extending to just below) the anatomic crown of the tooth, and the root canal (or canals), found in the anatomic root. Other notable features are the pulp horns; accessory, lateral, and furcation canals; canal orifices; isthmus; fins; apical deltas; and apical foramina. The outline of the pulp cavity generally corresponds to the external contour of the tooth. However, factors such as physiologic aging, pathosis, trauma, and occlusion all can modify its dimensions through the production of dentin or reparative (irregular secondary, irritational, and tertiary) dentin .

In single-rooted teeth, pulp chamber extends to the most apical portion of the cervical margin of the crown; in double/multirooted teeth, it extends to the floor of chamber located in the coronal third of the root.

* ( Pulp horns ) : 

 The pulp horns are important because the pulp in them is often exposed by caries, trauma, or mechanical invasion, which usually necessitates vital pulp or root canal procedures. Also, the pulp horns undergo rapid mineralization, along with reduction of the size and shape of the pulp chamber because of the formation of reparative/irritational dentin over time.

** ( Morphology of root canal ) :

 The root canal begins as a funnel-shaped canal orifice, generally at or just apical to the cervical line, and ends at the apical foramen (AF), which opens onto the root surface at or within 3 mm of the center of the root apex. Nearly all root canals are curved, particularly in a faciolingual direction, thereby posing problems during enlargement and shaping procedures because they are not evident on a standard two dimensional (2D) radiograph. In most cases, the number of root canals corresponds to the number of roots; however, an oval root may have more than one canal. 

** ( Accessory canals ) : 

 Accessory canals are minute canals that extend in a horizontal, vertical, or lateral direction from the pulp space to the periodontium. In 74% of cases they are found in the apical third of the root, in 11% in the middle third, and in 15% in the cervical third. The diameter, length, shape, and undulation may vary among accessory canals. Apical deltas are multiple accessory canals that branch out from the main canal at or near the root apex . Accessory canals contain connective tissue and vessels but may not supply the pulp with sufficient circulation to form a collateral source of blood flow. They are formed by the entrapment of periodontal vessels in Hartwig's epithelial root sheath during mineralization.24 They may play a significant role in the communication of disease processes, serving as avenues for the passage of irritants, primarily from the pulp to the periodontium, although communication of inflammatory processes may occur from either tissue.

 Accessory canals that are present in the bifurcation or trifurcation of multirooted teeth are referred to as furcation canals (or chamber canals). These channels form as a result of the entrapment of periodontal vessels during the fusion of the diaphragm, which becomes the pulp chamber floor. In mandibular molars, these canals occur in three distinct patterns. Pulpal inflammation can communicate to the periodontium via these canals and result in furcation lesions in the absence of demonstrable periodontal

disease. Likewise, the long-term presence of periodontal furcation lesions may influence the viability of the coronal or radicular pulp tissue when these aberrant channels are present .

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To be continued in the next episode 

#Dr_Ahmed_Adel_Abdeen