Sinus

What is sinus? I started my searching right now though procrastinate hold me for two years back. I thought sinus was located all over in a human body in every bone that we have. This is kinda funny that the fact it is so tickling. But my guess was wrong and the sinus only present in the area of the face. At least I got the idea haha. (Jk)

So here is the definition, sinus is a cavity within a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities.

In common usage, "sinus" usually refers to the paranasal sinuses, which are air cavities in the cranial bones, especially those near the nose and connecting to it. Most individuals have four paired cavities located in the cranial bone or skull.

Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. 

1. Maxillary sinuses are located under the eyes; 
2. Frontal sinuses are above the eyes; 
3. Ethmoidal sinuses are between the eyes 
4. Sphenoidal sinuses are behind the eyes.

I have Bone Island (aka Enostosis)

That is my OPG taken twice on 27 February and 13 March on 2017. Purpose of the first radiograph was taken to diagnose either both lower left and right 3rd molar is impacted or not but accidentally the bone island is diagnose. (* Regarding the third molar, radiograph was taken because clinically it seem like impacted but in radiograph, we diagnose it as operculum reside on top of the teeth.) Then, second radiograph was taken to look if the lesion show any changes and further investigations need to be done if the changes is positive.

I do some research on the internet that the bone island is not harm and is only benign. Only in rare cases will show more than 2 cm with symptoms. I did not feel pain before, and for my case I just acting like a surrender right now to wait any symptoms to appear if it happen. 

Then, basically the lesions are usually associated in long bone but for mine it is located at my mandible. So based on what I found, my case is rare, maybe.

Here are some of the points that I found so interesting to understand in detail about bone island:

DEFINITION AND PATHOGENESIS

• A benign, rarely symptomatic lesion, usually very small, of unknown etiology

IMPORTANCE

• Commonly found incidentally, and can be mistaken for lesions which require bx

CLINICAL FEATURES

• Usually asymptomatic
• Symptomatic lesions may become asymptomatic
• Most common in pelvis, ribs, proximal femur
• M = F
• Has been reported in Bannayan-Riley Ruvalcaba syndrome
• A higher incidence of bone islands has been reported in the hands and feet of pts with lepromatous leprosy and borderline types of leprosy but not in tuberculoid leprosy

RADIOLOGIC FEATURES

• 2mm-2cm sized round to oval blastic lesion blends with the cancellous bone in a "brush-like" manner
• Bone scan is cold or only warm (33% >15mm reported active on bone scan)
• CT scan will show the blastic nature of the lesion, accurately give dimensions, and demonstrate lack of periosteal reaction
• No surrounding bony destruction/cortical disruption, IM extension, or soft tissue mass associated with the lesion is best demonstrated with MRI (hypointense on T1 and T2)

GROSS PATHOLOGY

• Sharply defined hard lesion within the IM canal

HISTOLOGIC FEATURES

• Appearance of misplaced cortical bone within the IM canal: thick lamellar bone with Haversian systems
• No host bone lamellar bone trapping (seen in callus and osteosarcoma)
• No atypical nuclei or mitoses

DIFFERENTIAL CLINICOPATHOLOGIC DIAGNOSIS

• Metastatic bone disease (esp. with multiple lesions, eg, blastic breast mets or prostate CA)
• Osteoid osteoma
• Osteoblastoma
• Enchondroma
• Bone infarct
• Fibrous dysplasia
• Osteomyelitis
• Osteosarcoma

DISEASE COURSE AND TREATMENT

• Usually require no tx
• FU x-ray in one month and every 3 months (X4) in questionable lesions
• Biopsy in larger lesions to R/O osteosarcoma or in lesions that have size ? > 25% within 6mos, or >50% at 1yr

Source

http://www.orthopaedicsone.com/pages/viewpage.action?pageId=19071118

Woven Bone VS Lamellar Bone

Major constituent of the is  bone matrix. Woven and lamellar bone are termed on microscopic differentiation of the bone. Bone is formed by the hardening of this matrix entrapping the cells. When these cells become entrapped from osteoblasts they become osteocytes. The inorganic is mainly crystalline mineral salts and calcium and the organic part of matrix is mainly composed of Type I collagen. On microscope, two types of bone can be identified. These bones differ in the pattern of collagen forming the osteoid.

Woven bone

Woven bone is characterized by haphazard organisation of collagen fibers and is mechanically weak. Woven bone is produced when osteoblasts produce osteoid rapidly. It is present in:

• All fetal bones initially when the bone is laid down. Later it gets replaced by lamellar bone.
• After fractures  the initial bone that unites the fracture is woven bone. It too gets replaced by lamellar bone.
• Paget’s disease.

Woven bone is weaker, with a smaller number of randomly oriented collagen fibers, but forms quickly. It has been named due to woven appearance of fibrous matrix [see figure. Woven bone is basically either immature bone or pathologic bone. It  not stress oriented.  Compared to lamellar bone, woven bone has more osteocytes per unit of volume and  higher rate of turnover. Woven bone is weaker weaker and flexible than lamellar bone.

Lamellar bone

Lamellar bone is secondary bone created by remodeling of woven bone. Lamellar bone has a regular parallel alignment of collagen into sheets (lamellae) and is mechanically strong. It is highly organized in concentric sheets with a much lower proportion of osteocytes to surrounding tissue. Lamellar bone is stronger and filled with many collagen fibers parallel to other fibers in the same layer (osteons). In cross-section, the fibers run in opposite directions in alternating layers. This kind of structural arrangement assists in the bone’s ability to resist torsion forces.

Note: A microscope is necessary to differentiate between the two.

WHAT CAUSES GUM RECESSION?

Gum recession is the undesirable condition in which the edge of the gum tissue, called the “gingival margin”, moves down onto the root surface of one or more teeth.  An important concept to understand about gum recession is that the gum tissue is supported by the underlying bone, therefore when recession does occur, what we are really observing is a change to the gum position due to changes to the supporting bone. This may result in an unsightly appearance, increased tooth sensitivity, and/or an increased likelihood of getting a cavity on the root surface of the involved tooth/teeth.  For such a common condition, affecting over 50% of our adult population, you might think that the causes of gum recession have been well understood for decades. In reality, there is still much debate about its causative factors.  It has been proposed that recession is multifactorial, with one type being associated with anatomic factors and another type with physiological or pathological factors. Let’s list the factors that have been purported to cause gum recession, (clinically referred to as “gingival recession”), and explain the reasoning behind each factor.

1. Aging:  Getting older does not necessarily cause gingival recession however increased age is certainly correlated with an increased prevalence of gingival recession.  At least two studies have found that the frequency of gingival recession increased with age and was greater in men than in women of the same age. In essence, all of the factors that have the ability to affect gingival recession simply have longer to act the older a person becomes, therefore aging is a factor in the prevalence of recession.
2. Anatomic Factors: Because gum recession is simply a reflection of changes to the supporting bone beneath the gum tissue, a lack of bone growth around the roots of the teeth can be a cause of gingival recession. Therefore, if a lack of bone growth around a tooth root causes the width of a tooth to be wider than the bone it is housed in, gum recession will result. Similarly, if a tooth does not erupt in a normal direction out of the jaw bone (i.e. slightly to the side and not straight), there will be thin or inadequate bone on one side of the tooth and thick bone on the opposite side; thin bone is more susceptible to breakdown and thus may be a cause for gingival recession, while an absence of bone over the root surface, (referred to as a dehiscence), can also cause gum recession.
3. Orthodontic Tooth Movement:  The movement of teeth in the jawbones using orthodontics (wires, brackets, and springs) is normally a harmless process. On the other hand, occasionally teeth are moved with orthodontic forces in such a manner that the roots are pushed beyond their boney housing, called the alveolus.  This results in a portion of the root having no bone covering it, (usually on the cheek side rather than the tongue side), and therefore causes the gums to recede onto the root surface. This is the exact same process as the example in section B, only the movement of the tooth outside the alveolar bone is cause by a dentist rather than occurring naturally.
4. Periodontal Disease:  Periodontal disease is a bacterial process that causes breakdown of the bone around the roots of teeth. Just like the walls of a house hold up its roof, the bone supports the gum tissue.  If the bone gets destroyed in the process of periodontal disease, the gums may “collapse” in places around the teeth causing a movement of the gums relative to the enamel thus creating recession. Typically someone that has recession due to gum disease would have large spaces between their teeth and gums since the bone that would normally support the gum tissue between the roots is destroyed.
5. Trauma: Repeated trauma to gum tissue may cause the gum tissue to recede. This trauma can take many forms:
1. Vigorous tooth brushing, especially with a toothbrush that doesn’t have soft bristles.  Many studies have found a relationship between tooth brushing technique and gum recession; the purported cause of the recession is the “saw-like” mechanical abrasion of the toothbrush bristles against the gum tissue.  A V-shaped notch in the root surface often accompanies this gum recession.
2. Aberrant frenal attachment:  It is argued by some that the thin bridge of tissue that connects the inside of the lip to the gums (called a frenulum) may create a pulling force, which causes gum recession.  In the literature, there does not seem to be much agreement on this theory however.
3. Occlusal Trauma:  Occlusion is the term we use to describe the way the upper teeth come into contact with the lower teeth. The forces put upon the teeth are determined by many factors including the alignment of the teeth with one and other, the biting pressure put upon them, as well as which and how many teeth contact one and other. When one or more of these factors create “traumatic” stresses on the teeth, it is believed by some that these stresses are transferred to the alveolar bone surrounding the roots, thus creating gum recession. (Remember that gum recession is caused by a lack of supporting bone.)  
4. Hygiene:  It’s been determined that gingival recession occurs more frequently in individuals with good rather than poor oral hygiene. The theory is that those people who have good oral hygiene brush more frequently or too vigorously  thus creating gum recession.  There has been at least one study that found a positive correlation between brushing frequency and gingival recession.

Periodontal VS Periapical Abscess

Periodontal Abscess

• A periodontal abscess is a localized purulent inflammation in the periodontal tissue.
• It is also known as lateral abscess or parietal abscess.
• Abscess localized in gingiva, caused by injury to the outer surface of the gingiva, and not involving the supporting structure are called gingival abscesses.

Clinical Features:

1. Smooth, shiny swelling of the gingiva
2. Painful, tender to palpation
3. Purulent exudate
4. Increased probing depth
5. Mobile and/or percussion sensitive
6. Tooth usually vital

Treatment:

1. Anesthesia
2. Establish drainage

• Via sulcus is the preferred method
• Surgical access for debridement
• Incision and drainage
• Extraction

Periapical Abscess

• Also known as dentoalveolar abscess, alveolar abscess
• It is an acute or chronic suppurative process of the of the periapical region 
• It is the sequelae of periapical granuloma
• Phoenix abscess is an acute exacerbation of chronic periapical lesion.
• Chronic abscess is an asymptomatic, well-circumscribed area of suppuration that shows little tendency to spread from local area

Clinical Features:

1. Swelling
2. Warmth
3. Erythema
4. Fluctuant mass that usually extends toward the buccal side of the gum and to the gingival-buccal reflection
5. Parulis or "gum boil" (a soft, solitary, reddish papule located facial and apical to a chronically abscessed tooth that occurs at the endpoint of a draining dental sinus tract
6. Initially- tenderness, which is relieved by application of pressure
7. Later- extreme pain & slight extrusion from socket
8. Rapid extension to adjacent marrow spaces may occur, resulting in osteomyelitis

Treatment:

Drainage must be establish

• Open pulp chamber
• Extract the tooth