Acute periapical periodontitis, also termed acute apical periodontitis, acute periradicular periodontitis, or symptomatic periapical periodontitis.

The type of periapical periodontitis is usually classified according to whether it is an acute/symptomatic process or a chronic/asymptomatic process.

The symptoms of gingivitis are somewhat non-specific and manifest in the gum tissue as the classic signs of inflammation:

- Swollen gums

- Bright red or purple gums

- Gums that are tender or painful to the touch

- Bleeding gums or bleeding after brushing and/or flossing

- Bad breath (halitosis)

Additionally, the stippling that normally exists in the gum tissue of some individuals will often disappear and the gums may appear shiny when the gum tissue becomes swollen and stretched over the inflamed underlying connective tissue. The accumulation may also emit an unpleasant odor. When the gingiva are swollen, the epithelial lining of the gingival crevice becomes ulcerated and the gums will bleed more easily with even gentle brushing, and especially when flossing.

Gingivitis is a non-destructive disease that occurs around the teeth. The most common form of gingivitis, and the most common form of periodontal disease overall, is in response to bacterial biofilms (also called plaque) that is attached to tooth surfaces, termed "plaque-induced gingivitis".

While some cases of gingivitis never progress to periodontitis, data indicates that periodontitis is always preceded by gingivitis.

Gingivitis is reversible with good oral hygiene; however, without treatment, gingivitis can progress to periodontitis, in which the inflammation of the gums results in tissue destruction and bone resorption around the teeth. Periodontitis can ultimately lead to tooth loss. The term means "inflammation of the gum tissue".

In the early stages, periodontitis has very few symptoms, and in many individuals the disease has progressed significantly before they seek treatment.

Symptoms may include:

- Redness or bleeding of gums while brushing teeth, using dental floss or biting into hard food (e.g., apples) (though this may occur even in gingivitis, where there is no attachment loss)

- Gum swelling that recurs

- Spitting out blood after brushing teeth

- Halitosis, or bad breath, and a persistent metallic taste in the mouth

- Gingival recession, resulting in apparent lengthening of teeth. (This may also be caused by heavy-handed brushing or with a stiff toothbrush.)

- Deep pockets between the teeth and the gums (pockets are sites where the attachment has been gradually destroyed by collagen-destroying enzymes, known as collagenases)

- Loose teeth, in the later stages (though this may occur for other reasons, as well)

Patients should realize gingival inflammation and bone destruction are largely painless. Hence, people may wrongly assume painless bleeding after teeth cleaning is insignificant, although this may be a symptom of progressing periodontitis in that patient.

The "severity" of disease refers to the amount of periodontal ligament fibers that have been lost, termed "clinical attachment loss". According to the American Academy of Periodontology, the classification of severity is as follows:

- Mild: of attachment loss

- Moderate: of attachment loss

- Severe: ≥ of attachment loss

It is one of the seven destructive periodontal diseases as listed in the 1999 classification.

In the early stages, chronic periodontitis has few symptoms and in many individuals the disease has progressed significantly before they seek treatment.

Symptoms may include the following:

- Redness or bleeding of gums while brushing teeth, using dental floss or biting into hard food (e.g. apples) (though this may occur even in gingivitis, where there is no attachment loss)

- Gum swelling that recurs

- Halitosis, or bad breath, and a persistent metallic taste in the mouth

- Gingival recession, resulting in apparent lengthening of teeth. (This may also be caused by heavy-handed brushing or with a stiff tooth brush.)

- Deep pockets between the teeth and the gums (pockets are sites where the attachment has been gradually destroyed by collagen-destroying enzymes, known as "collagenases")

- Loose teeth, in the later stages (though this may occur for other reasons as well)

Gingival inflammation and bone destruction are often painless. Patients sometimes assume that painless bleeding after teeth cleaning is insignificant, although this may be a symptom of progressing chronic periodontitis in that patient.

Subgingival calculus is a frequent finding.

There is a slow to moderate rate of disease progression but the patient may have periods of rapid progression ("bursts of destruction"). Chronic periodontitis can be associated with local predisposing factors(e.g. tooth-related or iatrogenic factors). The disease may be modified by and be associated with systemic diseases (e.g. diabetes mellitus, HIV infection) It can also be modified by factors other than systemic disease such as smoking and emotional stress.

Major risk factors: Smoking, lack of oral hygiene with inadequate plaque biofilm control.

Measuring disease progression is carried out by measuring probing pocket depth (PPD) and bleeding indices using a periodontal probe. Pockets greater than 3mm in depth are considered to be unhealthy. Bleeding on probing is considered to be a sign of active disease. Discharge of pus, involvement of the root furcation area and deeper pocketing may all indicate reduced prognosis for an individual tooth.

Age is related to the incidence of periodontal destruction: "...in a well-maintained population who practises oral home care and has regular check-ups, the incidence of incipient periodontal destruction increases with age, the highest rate occurs between 50 and 60 years, and gingival recession is the predominant lesion before 40 years, while periodontal pocketing is the principal mode of destruction between 50 and 60 years of age."

In the early stages some patients may complain of a feeling of tightness around the teeth. Three signs/symptoms must be present to diagnose this condition:

- Severe gingival pain.

- Profuse gingival bleeding that requires little or no provocation.

- Interdental papillae are ulcerated with necrotic slough. The papillary necrosis of NUG has been described as "punched out".

Other signs and symptoms may be present, but not always.

- Oral malodor (intraoral halitosis).

- Bad taste (metallic taste).

Malaise, fever and/or cervical lymph node enlargement are rare (unlike the typical features of herpetic stomatitis). Pain is fairly well localized to the affected areas. Systemic reactions may be more pronounced in children. Cancrum oris (noma) is a very rare complication, usually in debilitated children. Similar features but with more intense pain may be seen in necrotizing periodontitis in HIV/AIDS.

Necrotizing gingivitis is part of a spectrum of disease termed necrotizing periodontal diseases. It is the most minor form of this spectrum, with more advanced stages being termed necrotizing periodontitis, necrotizing stomatitis and the most extreme, cancrum oris.

Acute necrotizing ulcerative gingivitis (ANUG) refers to the clinical onset of NUG. The word acute is used because usually the onset is sudden. Other forms of NUG may be chronic or recurrent.

Necrotizing ulcerative periodontitis (NUP) is where the infection leads to attachment loss, and involves only the gingiva, periodontal ligament and alveolar ligament. Progression of the disease into tissue beyond the mucogingival junction characterizises necrotizing stomatitis.

In dentistry, calculus or tartar is a form of hardened dental plaque. It is caused by precipitation of minerals from saliva and gingival crevicular fluid (GCF) in plaque on the teeth. This process of precipitation kills the bacterial cells within dental plaque, but the rough and hardened surface that is formed provides an ideal surface for further plaque formation. This leads to calculus buildup, which compromises the health of the gingiva (gums). Calculus can form both along the gumline, where it is referred to as supragingival ("above the gum"), and within the narrow sulcus that exists between the teeth and the gingiva, where it is referred to as subgingival ("below the gum").

Calculus formation is associated with a number of clinical manifestations, including bad breath, receding gums and chronically inflamed gingiva. Brushing and flossing can remove plaque from which calculus forms; however, once formed, it is too hard and firmly attached to be removed with a toothbrush. Calculus buildup can be removed with ultrasonic tools or dental hand instruments (such as a periodontal scaler).

Type II would mostly cause discolouration to the primary teeth. Affected teeth usually appear as brownish-blue, brown or yellow. Translucent “opalescence” is often one of the characteristics to describe teeth with DD-2. In some cases teeth might show slightly amber coloured but in most of the cases permanent teeth are unaffected and appear normal regardless of colour, shape and size. Dental X-rays is the key to diagnose dentine dysplasia, especially on permanent teeth. Abnormalities of the pulp chamber is the main characteristic to make a definitive diagnosis.

In the primary teeth, coronal dentin dysplasia may appear similar to Dentinogenesis Imperfecta type II (DG-II) but if abnormalities features appear to be more pronounced in the permanent teeth, then consider changing the diagnosis to DGI-II instead of DD-2.

In other words, affect primary teeth usually have abnormal shaped or shorter than normal roots . “Crescent/ half-moon shaped” pulp chamber remnant in permanent teeth can be seen on x-rays. The roots may appear to be darker or radiolucent/ pointy and short with apical constriction. Dentine is laid down abnormally and causes excessive growth within the pulp chamber. This will reduce the pulp space and eventually cause incomplete and total pulp chamber obliteration in permanent teeth. Sometimes periapical pathology or cysts can be seen around the root apex. Most cases of DD associated with peri-apical radiolucency/ pathology have been diagnosed as radicular cysts, but some of them have been as diagnosed peri-apical grauloma instead.

Necrotic pulp is a finding in dentistry to describe dental pulp within a tooth which has become necrotic. Directly meaning, death of the pulp. It is a finding of interest to dentists as the process of pulp death may be painful causing a toothache.

Sequelae of a necrotic pulp include acute apical periodontitis, dental abscess or radicular cyst and discolouration of the tooth.

Tests for a necrotic pulp include: vitality testing using a thermal test or an electric pulp tester. Discolouration may be visually obvious, or more subtle.

Treatment usually involves endodontics or extraction.

Periodontitis as a manifestation of systemic diseases is one of the seven categories of periodontitis as defined by the American Academy of Periodontology 1999 classification system. At least 16 systemic diseases have been linked to periodontitis. These systemic diseases are associated with periodontal disease because they generally contribute to either a decreased host resistance to infections or dysfunction in the connective tissue of the gums, increasing patient susceptibility to inflammation-induced destruction.

These secondary periodontal inflammations should not be confused by other conditions in which an epidemiological association with periodontitis was revealed, but no causative connection was proved yet. Such conditions are coronary heart diseases, cerebrovascular diseases and erectile dysfunction.

Ankylosis of deciduous teeth ("submerged teeth") may rarely occur. The most commonly affected tooth is the mandibular (lower) second deciduous molar. Partial root resorption first occurs and then the tooth fuses to the bone. This prevents normal exfoliation of the deciduous tooth and typically causes impaction of the permanent successor tooth. As growth of the alveolar bone continues and the adjacent permanent teeth erupt, the ankylosed deciduous tooth appears to submerge into the bone, although in reality it has not changed position. Treatment is by extraction of the involved tooth, to prevent malocclusion, periodontal disturbance or dental caries.

The main types of dental abscess are:

- Periapical abscess: The result of a chronic, localized infection located at the tip, or apex, of the root of a tooth.

- Periodontal abscess: begins in a periodontal pocket (see: periodontal abscess)

- Gingival abscess: involving only the gum tissue, without affecting either the tooth or the periodontal ligament (see: periodontal abscess)

- Pericoronal abscess: involving the soft tissues surrounding the crown of a tooth (see: Pericoronitis)

- Combined periodontic-endodontic abscess: a situation in which a periapical abscess and a periodontal abscess have combined (see: Combined periodontic-endodontic lesions).

Dental plaque is a biofilm or mass of bacteria that grows on surfaces within the mouth. It is a sticky colorless deposit at first, but when it forms tartar, it is often brown or pale yellow. It is commonly found between the teeth, on the front of teeth, behind teeth, on chewing surfaces, along the gumline, or below the gumline cervical margins. Dental plaque is also known as microbial plaque, oral biofilm, dental biofilm, dental plaque biofilm or bacterial plaque biofilm.

Progression and build-up of dental plaque can give rise to tooth decay – the localised destruction of the tissues of the tooth by acid produced from the bacterial degradation of fermentable sugar – and periodontal problems such as gingivitis and periodontitis; hence it is important to disrupt the mass of bacteria and remove it. Plaque control and removal can be achieved with correct daily or twice-daily tooth brushing and use of interdental aids such as dental floss and interdental brushes.

Oral hygiene is important as dental biofilms may become acidic causing demineralization of the teeth (also known as dental caries) or harden into dental calculus (also known as tartar). Calculus cannot be removed through tooth brushing or with interdental aids, but only through professional cleaning.

A great many diseases involve the mouth, jaws and orofacial skin. Some example pathologies which can involve the oral and maxillofacial region are listed. Some are more common than others, and this list is by no means complete. The examples are considered according to a surgical sieve.

PLS is characterized by periodontitis and palmoplantar keratoderma. The severe destruction of periodontium results in loss of most primary teeth by the age of 4 and most permanent teeth by age 14. Hyperkeratosis of palms and soles of feet appear in first few years of life. Destructions of periodontium follows almost immediately after the eruption of last molar tooth. The teeth are involved in roughly the same order in which they erupt.

Repair with cementum or dentin occurs after partial root resorption, fusing the tooth with the bone. It may occur following dental trauma, especially occlusal trauma, or after periapical periodontitis caused by pulp necrosis. Ankylosis itself is not a reason to remove a permanent tooth, however teeth which must be removed for other reasons are made significantly more difficult to remove if they are ankylosed.

Apical abscesses can spread to involve periodontal pockets around a tooth, and periodontal pockets cause eventual pulp necrosis via accessory canals or the apical foramen at the bottom of the tooth. Such lesions are termed periodontic-endodontic lesions, and they may be acutely painful, sharing similar signs and symptoms with a periodontal abscess, or they may cause mild pain or no pain at all if they are chronic and free-draining. Successful root canal therapy is required before periodonal treatment is attempted. Generally, the long-term prognosis of perio-endo lesions is poor.

Oral and maxillofacial pathology (also termed oral pathology, stomatognathic disease, dental disease, or mouth disease) refers to the diseases of the mouth ("oral cavity" or "stoma"), jaws ("maxillae" or "gnath") and related structures such as salivary glands, temporomandibular joints, facial muscles and perioral skin (the skin around the mouth). The mouth is an important organ with many different functions. It is also prone to a variety of medical and dental disorders.

The specialty oral and maxillofacial pathology is concerned with diagnosis and study of the causes and effects of diseases affecting the oral and maxillofacial region. It is sometimes considered to be a specialty of dentistry and pathology. Sometimes the term head and neck pathology is used instead, but this might imply that the pathologist deals with otorhinolaryngologic disorders (i.e. ear, nose and throat) in addition to maxillofacial disorders. In this role there is some overlap between the expertise of head and neck pathologists and that of endocrine pathologists.

For those patients with periodontitis as a manifestation of hematologic disorders, coordination with the patient's physician is instrumental in planning periodontal treatment. Therapy should be avoided during periods of exacerbation of the malignancy or during active phases of chemotherapy, and antimicrobial therapy might be considered when urgent treatment must be performed when granulocyte counts are low.

Common marginal gingivitis in response to subgingival plaque is usually a painless condition. However, an acute form of gingivitis/periodontitis, termed acute necrotizing ulcerative gingivitis (ANUG), can develop, often suddenly. It is associated with severe periodontal pain, bleeding gums, "punched out" ulceration, loss of the interdental papillae, and possibly also halitosis (bad breath) and a bad taste. Predisposing factors include poor oral hygiene, smoking, malnutrition, psychological stress, and immunosuppression. This condition is not contagious, but multiple cases may simultaneously occur in populations who share the same risk factors (such as students in a dormitory during a period of examination). ANUG is treated over several visits, first with debridement of the necrotic gingiva, homecare with hydrogen peroxide mouthwash, analgesics and, when the pain has subsided sufficiently, cleaning below the gumline, both professionally and at home. Antibiotics are not indicated in ANUG management unless there is underlying systemic disease.