Antimicrobials used in dentistry

Chemotherapy is the use of chemicals to destroy or inhibit the growth of cells. Two broad classes of chemotherapeutic agents are used in pharmacology: 

1. antimicrobials and 
2. anticancer drugs. 

The basis of antimicrobial chemotherapy is a differential sensitivity of the patient and microbe cells to the action of the drug. The drug may affect a structural component of the target cell which is not found in the patient, for example, the bacterial cell wall. Alternatively, a chemotherapeutic agent may inhibit a metabolic pathway peculiar to the microbe cells, for example, synthesis of folate.

Parotid Fistula

     Normally there is one opening of the parotid gland which is located in buccal vestibule opposite the upper 2nd molar tooth.

     Parotid fistula is a patent tract connecting a parotid gland or duct to the exterior apart from the parotid duct opening.

Photo 1. Pre-operative picture of parotid fistula with leakage of serous fluid from the fistulous tract and scarring of surrounding area (red circle) [1]

     Parotid fistula may be of two types

    1. Glandular: It arises directly from gland. It shows minimal discharge during rest or eating.

2. Ductal: It arises from duct. It shows profuse discharge during eating.

Parotid fistula may be extra oral or intraoral.

Extraoral fistulas are seen in the preauricular region or near the angle of mandible (see photo 1 and 2).

Photo 2. showing discharge of serous fluid from the right cheek in the angle of mandible region [2]

Causes
1. After superficial parotidectomy.
2. After drainage of parotid abscess.
3. After biopsy or Trauma.
4. Post surgical

Clinical Features
1.  Discharging fistula in the parotid region of the face, and discharge is more during eating.
2. Tenderness and induration.
3. Trismus if it gets infected

     Diagnosis
1.  Sialography to find out the origin of the fistula whether from the parotid gland or duct or ductules.
2. Fistulogram or CT fistulogram.
3. Culture of discharge if infection is suspected
4. MRI to assess soft tissues involvement

    Treatment
Ø Surgical stripping of the fistula tract
Ø Anticholinergics in post-operative period- Hyoscine bromide (Probanthine) reduce discharge
Ø Immediate post surgical fistulas can close spontaneously in such cases
Ø Newman Seabrock's operation: used for removal of anomalous arotid fistula
Ø If there is stenosis at the orifice of the Stenson's duct, papillotomy at the orifice may help.
Ø Total conservative parotidectomy is done in failed cases conserving the facial nerve
 

Ref:

1. Parotid fistula secondary to suppurative parotitis in a 13-year-old girl: a case report
2. Parotid Fistula : Report of Two Cases and Literature Review Introduction

Injections Techniques

Darsogluteal Intramuscular Injections

Kaposi sarcoma

 

Kaposi sarcoma (in AIDS):

Important points to remember about Kaposi Sarcoma

Kaposi's sarcoma is a type of cancer that forms in the lining of blood and lymph vessels.

Kaposi's sarcoma or oral cavity

Kaposi's sarcoma of the skin

Clinical Features

• It is the most common malignancy in AIDS.
• It is associated with the infection with a virus called the Kaposi sarcoma associated herpesvirus (KSHV), also known as human herpesvirus 8 (HHV8).
• The commonly affected sites are palate, gingiva, tongue, and oropharynx or the skin of the face and feet.
• It is seen early in the course of the disease. It can sometimes be confused with Bacillary angiomatosis.
• There is a specific histologic stain for Kaposi sarcoma known as Warthin-Starry stain.
• With the use of HAART, incidence of KS is decreasing and soon NHL may become the most common malignancy associated with AIDS.

 

Cemento Osseous Dysplasia

Cemento-osseous dysplasia (COD) is a benign fibro-osseous lesion of bone characterized by the replacement of normal bone by fibrous tissue and subsequently followed by its calcification with osseous and cementum-like material. It arises from the fibroblasts of the periodontal ligaments.

It is mostly asymptomatic in nature and requires no treatment. When secondarily infected, it becomes symptomatic and intervention is required.

Orthopantamogram showing a well-defined radiopaque mass in the right mandible region extending from the distal root of 45 to the mesial root of 47 [1]

As per WHO, there are three clinical presentation of cemento-osseous dysplasia.

1. Periapical
2. Focal
3. Florid

Periapical cemento-osseous dysplasia

These occur in the anterior mandible and involve only a few adjacent teeth.

Focal cemento-osseous dysplasia.

involve few teeth in posterior mandible

Florid cemento-osseous dysplasia or Familial gigantiform cementoma

It is a more extensive form. it occurs bilaterally in mandible or in all jaw quadrants.

Ref:

1. Focal cemento-osseous dysplasia

Periapical Granuloma

The cells of periapical granuloma which are predominantly lymphocytes increase by division at the periphery. 

There are hyperaemia and oedema of the PDL; localised increase in the vascularity leads to local bone resorption mediated by osteoclast mediated delayed hypersensitivity. In the specimen slide, cholesterol crystals having needle-like appearance, and eosinic hyaline bodies known as Rushton bodies are seen. Macrophages and multinucleated giant cells are also seen. Epithelium is present.

The cells in the centre are separated from their source of nutrition; hence degenerate and liquefy. This results in an epithelium lined cavity filled with fluid known as periapical cyst.

Treatment involves RCT with apicoectomy or extraction with curettage.

Ref:

1. Radiographic Interpretation between Periapical Cysts and Periapical Granuloma- A Diagnostic Tool
2. Periapical cyst/radicular cyst

Sequelae of Infection of Dental Pulp

Periapical infection with Streptococci & Staphylococci

Majority of streptococci produce hyaluronidase, an enzyme that dissolves hyaluronic acid which is a universal intercellular cementing substance. It helps in the spread of infection. Usually staphylococci are good producers of hyaluronidase, so there is no spread of infection and the infection becomes localised in the form of abscess in case of staph infection.

Oral Cancer

Oral cancer is associated with significant morbidity and mortality. Early presentations of oral cancer are usually asymptomatic, whereas late presentations include pain, discomfort, reduced mobility of the tongue, increased mobility of the teeth or an inability to wear dentures. Oral cancer varies in appearance and can mimic many other oral mucosal diseases.

Squamous cell carcinoma of the left anterior ventral surface of the tongue

Squamous cell carcinoma of the left mandibular alveolus

Oral cancer can mimic many other oral mucosal diseases, so early specialist referral is required for investigation and biopsy of any suspicious lesion. 

Any suspicious lesion needs early specialist referral for investigation and biopsy.

Squamous cell carcinoma is the most common oral malignancy, which arises from the epithelium of the oral cavity. Oral squamous cell carcinoma can affect any part of the oral mucosa; however, it most commonly occurs on the lateral surfaces of the tongue, the floor of the mouth or the gingivae. 

Risk factors for oral squamous cell carcinoma  

1. advanced age 
2. male gender 
3. smoking or tobacco use 
4. alcohol use 
5. infection by oncogenic viruses (eg human papillomavirus) 
6. personal or family history of squamous cell carcinoma of the head and neck 
7. history of cancer therapy 
8. prolonged immunosuppression 
9. areca nut (betel quid) chewing. 
10. Genetic susceptibility, environment, occupation and diet may also contribute to the development of oral squamous cell carcinoma. 

Cancers originating from the salivary glands and supporting nonepithelial tissues are less common than squamous cell carcinoma. Metastatic cancers to the oral soft tissues and jawbones commonly originate from primary malignancies in the breast, prostate, kidneys or lungs. Leukaemia and lymphoma may also present in the oral cavity. 

 

The treating specialist should perform the biopsy of an oral mucosal lesion. In rural or remote areas where a delay in specialist review is expected, seek expert advice on biopsy technique. A punch biopsy is not appropriate.

 

References:

1. Therapeutic guidelines (Oral & Dental) 2019 

Oral Leukoplakia

Oral leukoplakia (OL) is a clinical term for a nonremovable white lesion that is not easily recognisable as any particular condition and therefore requires further investigation.

Oral leukoplakia manifests as patches that are bright white and sharply defined. The surfaces of the patches are slightly raised above the surrounding mucosa.

Oral leukoplakia may be homogenous (uniform lesion often with a fissured surface), or nonhomogeneous (with surface irregularity and textural or colour variation for example speckled-see below given photograph.

Stages and Phases of Anaesthesia

Assessment of the depth of anaesthesia 

Anaesthesia has been described as a series of four Stages. 

Stage 1

The period between administration of an anaesthetic and loss of consciousness. 

Stage 2

The period after loss of consciousness, which may include actions such as uncontrolled movement, delirium, vocalization.

Stage 3 

The level at which surgery can be performed. Stage 3 anaesthesia is divided into four planes. 

1. Plane 1: "light" anaesthesia - the animal still has blink and swallowing reflexes, and regular respiration.
2. Plane 2: "surgical" anaesthesia - the animal has lost blink reflexes, pupils become fixed and respiration is regular.
3. Plane 3: "deep" anaesthesia - the animal starts losing the ability to use the respiratory muscles and breathing becomes shallow; may require assisted ventilation. The surgeries are performed in this plane.
4. Plane 4: the animal loses all respiratory effort, and breathing may stop entirely. 

Stage 4

Anaesthetic crisis! Respiratory arrest and death from circulatory collapse imminent.