Tetracycline

Tetracyclines have the broadest antimicrobial spectrum.They intefere with bacterial protein synthesis.They are bacteriostatic and resistance to them develops frequently.They are active against many gram positive and gram negative pathogenic bacteria strains except for those of Pseudomona aeruginosa.

Adverse reactions:

Tetracyclines are best used for minor infective conditions in penicillin allergic oral and antral cases.It is only partially absorbed from the gut,sufficient concentrations remain in the intestine to alter the flora which may give rise to local complications such as discomfort,diarrhoea and suppression of vitamin K synthesis.Other problems include heartburn,nausea and vomiting due to gastric mucosal irritation,skin rashes and photosensitization.

Absorption is reduced by chelation to calcium in dairy products and even more so with antacids and iron preparations.The plasma half life varies with the tetracycline and is increased in renal failure except for doxycycline which is not eliminated by the kidney and therefore may be used with impaired renal function.

Superinfection may occur with candida albicans producing a sore mouth or thrush in addition to a black hairy tongue,diarrhoea and pruritis.Superinfection with staphylococci,proteus or pseudomonas causing a fulminating fatal enteritis is also possible if used in heavy prolonged dosage.Oral,anal and vaginal superinfection can be avoided by use of nystatin or amphotericin and vaginal suppositories.Tetracycline are selectively chelated by the calcium of growing bones and teeth both in the foetus and children causing yellowish or brownish discoloration of the enamel.It can also cause enamel hypoplasia.Tetracycline must be avoided in children until twelve years of age.

Dosage:

Dosage is teracycline dosage is either capsules or tablets 250 mg 6 hourly.Demeclocycline is more readily absorbed from the gut and excreted more slowly and therefore 300 mg may be given 12 hourly.

Parenteral adminstration is best by intermittent intravenous infusion of 1 gram of tetracycline or oxytetracycline in 0-9 percent sodium chloride each 24 hours divided in to 2 or 4 doses each infused over 5 to 10 minutes.Intramuscular injections are painful.

Metronidazole

Metronidazole is a narrow spectrum antibiotic active specifically against anaerobes.With improved culture techniques there has been an increased awareness of the pathogenic role of anaerobes such as bacteroides either alone or in conjunction with other organisms in the production of soft tissue infections.It is active against bacteroides,Clostridium  difficile and some protozoa such as trichomonas and Giardia lamblia.It has proved highly effective in the management of most oral surgical infections in addition to acute ulcerative gingivitis.

Metronidazole is well absorbed when taken by mouth and can be given either 400 mg 12 hourly or 200 mg  8 hourly.Metronidazole intravenous infusion 500 mg 12 hourly is also very helpful.The drug penetrates abscesses well and crosses the blood-brain barrier.

Adverse reactions:

The side effects include an unpleasant metallic taste,nausea and gastro-intestinal upsets.It also causes rashes occasionally.Prolonged use may cause a reversible neuropathy.Some patients experience an antabuse effect with alcohol.

Endodontic endosseous implants

Endosseous implants may be used to stabilise teeth where attached root length has been lost due to some pathologic al process or to stabilize unsupported teeth following periodontitis.In case of doing this technique for periodontically involved teeth,it is recommended only if there has been a complete control of the periodontal bone loss and active periodontal infection.The implant may be a fabricated nickel chrome wire measuring 1.3 mm or 1.5 mm in diameter.It must be of sufficient length to extend in to the original position of the tooth apex and must also penetrate about 5 mm in to the sound bone beneath.At the coronal end sufficient wire will be required both for manipulation and also for construction of a core to carry a crown.Ready made endodontic implants with appropriate bone drills are also available commercially.

Procedure:

1.Firstly the canal must be carefully and completely reamed to the implant diameter.

2.The apical area is then exposed surgically,irrigated and dried with ribbon aguze and the canal is also dried.

3.The cement is then applied to the canal walls.(EPA that is epoxyorthobenzoic acid or Cold cure acrlic can be used for this purpose)

4.The coronal half of the implant is also covered with cement and then the implant is inserted in to the canal and through the apex where it is carefully wiped with a sterile cotton wool before removing the ribbon gauze pack.

5.The post may be tapped firmly in to the overlying bone and any excess cement is carefully removed and washed out of the bone wound.

6.The coronal end is closed by an apicectomy.

Pyogenic infections of the soft tissues

Pyogenic infections of the soft tissues

Infections of the soft tissues around the jaws originate froma periapical infection related to a tooth or root,percoronal or periodontal infections or a secondary infected cyst or odontome.The infection causing organism may also enter the soft tissues from a penetrating wound with a retained foreign body which can be caused by a contaminated needle or a furuncle of the overlying skin.

The routes by which the infection can spread are:

1.By direct continuity through the tissues.

2.By the lymphatics to the regional lymphnodes and then in to the blood stream.If infection establishes itself in the lymphnodes then secondary abscesses may develop.

3.By the blood stream-Local thrombophlebitis may rarely propagate along the veins,entering the cranial cavity via emissary veins to produce cavernous sinus thrombophlebitis.Organism or infected emboli may be swept away in to the blood stream leading to bacteraemia,septicaemia and pyaemia with the development of embolic abscesses.

Factors affecting the ability of the infection to spread:

1.The type and virulence of the organisms.

2.A failure to drain accumulations of the pus.Pus contains large numbers of organisms and their toxins and drainage of an abscess usually leads within a matter of hours to a marked reduction in malaise and a fall in the patient’s temperature and pulse rate.

3.The state of the patient’s health generally which may de adversely affected by a virus infection,diabetes,malnutrition or alcoholism.

4.The ffectiveness of the patient’s immune mechanism.It takes time for the body’s immune mechanisms to be mobilized to combat an organism.

Anatomical factors influcencing direction  of infection within the tissues:

1.The site of the source of the infection and the particular segment of the jaw involved.

2.The point at which the pus escapes from the bone and discharges in to the soft tissues.

3.The natural barrriers to the spread of pus in the tissues such as by layers of fascia or muscle or the jaw bones .

Damage to the condyle of the temperomandibular joint

Injury or disease affecting the condyle during childhood can affect the condylar growth centre and produce changes in mandibular growth.Trauma to the condyle,infection and Still’s disease cause damage to the condyle.Infection may reach the condyle by direct spread from osteomyelitis or as a result of a suppurative arthritis.The mandible can be considered as composed of three elements,a bar of bone which stretches from the condyle to te mental eminence,the alveolar process and the muscular processes of the coronoid and angle.The condylar growth centre is responsible for the growth in length of the basic bar or arch of bone.If growth ceases the distance between the condyle and the point of the chin remains the same.As the maxilla grows downwards in relation to the joint the chin end of the bar is tilted down in to the neck.The alveolar process in the incisor region grows upwards and forwards towards the maxilla.Both the muscular processes achieve a near normal size and the coronoid is elongated and the sizeable angle accentuates the facial notch in camparison with the condyle.

Dislocation of the temperomandibular joint

Dislocation of the condyle head upwards and forwards in to the temporal fossa occurs when the masticatory muscles contract at a time when the mouth is open ot its greatest extent or when a blow is delevered to the chin,again when the mouth is wide open.The condyle moves normally to a point beyond and above  the lowest point on the eminentia on a cineradiograph.The jaw is controlled at this point by the balanced pull of the muscles and can be brought back smoothly under the eminentia and up in to the fossa.A temporary lack of balance can casue a dislocation to occur.

Treatment of the dislocation:

Reduction is accomplished by downward pressure with the padded thumbs on the lower molars,together with an upwards and backwards force applied to the underside of the chin with the fingers.If the patient has severe pain,anaesthesia is necessary to produce the muscular relaxation needed to complete the reduction.A prop or gag between the molar teeth acting as a fulcrum,this pressure easily pushes the condyles over the eminentia.

Chronic dislocation is seen in many edentulous patients.A condylectomy can be performed with replacement of the mandible.

Haemostatic agents to stop haemorrhage

Haemostatic agents help to stop haemorrhage from a surgical wound or an extracton site.The following agents given below serve as haemostatic agents.


1.Thrombin can be apllied on a cotton wool and placed in the wound.

2.Russell viper venom can also be placed on a cotton wool and placed in the surgical wound site.

3.A surgicel which is oxidised regenerated cellulose can be packed in to the tissue.It is absorbable and safe to use.The surgicel partially dissolves to form acid products which coagulate plasma proteins together with Hb to form a black and sticky clot.

4.Bone wax(Horsely’s) consisting of bees wax 7 parts by weight,olive oil 2 parts and phenol 1 part is packed in to the surgical wound.This helps in controlling the haemorrhage

Haemostasis by application of pressure

Haemostasis can be obtained by application of pressure..The methods given below can be used to stop haemorrhage from a wound.

1.A dry gauze swab is packed in to the wound over the bleeding area and digital pressure is maintained over the swab for a minimum of 2 and a half minutes.

2.Swab is soaked in hot normal saline solution at 48.8 degrees C and then it is well wrung out before applying to the wound.

3.A surgical pack can be applied.The surgical pack consists of a half inch ribbon gauze soaked in white head’s varnish(benzoin 10 parts,storax 7.5 parts,balsam of Tolu 5 parts,iodoform 10 parts and solvent ether to 100 parts)The pack must be sewn in to position to prevent any displacement.

Custom acrylic temporary crown

For a custom acrylic temporary crown,an indirect technique is preferred over the direct technique for pulpal protection and accuracy.

Fabrication armamentarium:

1.Diagnostic cast

2.Utility cast

3.No.7 wax spatula

4.Same side impression trays

5.Alginate

6.Rubber bowl

7.Spatula

8.B.P.blade no.25

10.Large camel hair brush

11.Cement spatula

12.Dappen dish

13.Seperating medium

14.Acrylic monomer and polymer

15.Heavy rubber band

16.Straight handpiece

17.Seperating disc on mandrel

18.Sand paper disc on moore mandrel

Preparation:

Cut away thin edges in the gingival area of the overimpression and make an alginate impression of the prepared tooth.

Try the plaster cast in to the overimpression before proceeding.

Seperating medium is painted on the plaster cast.

Mix the acrylic in the dappen dish.

Acrylic is placed in the overimpression.

The cast is seated firmly in the overimpression.

Hold the cast in place with a rubber band.

If the cast is placed to one side,the temporary restoration will be deficient.

Overseating of the cast will produce a temporary restoration with a thin occlusal surface.

The cast can be broken to remove the temporary restoration.

Remove any plaster remaining in the temporary restoration.

Grind off the acrylic flash with a carborundrum disc.

Finish smoothing the margins with a sandpaper disc.

Now the occlusion on the restoration is checked in the mouth.

Occlusion is adjusted outside the mouth.

The restoration is polished with pumice.

The zinc oxide - eugenol cement is often mixed with a small amount of petrolatum.

An explorer is used to remove cement from the gingival crevice.

Related articles:

Anterior polycarbonate crown

Preformed anatomic metal crown

Post operative care for trans-alveolar extraction

Here are the post-operative care instructions after a trans-alveolar extraction:-

a.Antibiotic therapy:

Whenever a significant amount of bone is removed during a trans-alveolar extraction,so it is appropriate to prescribe a 3 to 5 day course of antibiotic therapy to reduce the risk of post-operative wound infection.Metronidazole 200 mg TDS(thrice a day) or Pencillin 250 mg are given mostly.These drugs are given provided the patinet has had no previous adverse drug reactions to these drugs.

b.Suture removal:

when non-absorbable sutures have been placed they should be removed after 7 days.Even in cases where absorable sutures are used,if the patient finds it irritating it may be removed.Sutures placed to control haemorrhage can be removed after 48 hours.If sutures are placed to repair an oro-antral fistula,it has to be left for 10 days before removing the sutures.

c.Post-surgical review:

It is always better to go to the dentist for a review even if there are no problems.

Related articles:

Trans-alveolar extraction advantages