*2.3.2 Patterns and trends of alveolar bone loss*

Periodontitis is usually asymptomatic chronic inflammatory condition caused by bacterial aggregation which affects the crest of the alveolar process by reducing the normal height in a vertical and/or a horizontal manner; furthermore, bone loss might be presented in a localized or a generalized form [35]. Bone destruction can be detected using several radiographical techniques that evaluate the quantity of the remaining bone and subsequently estimating the amount of bone loss on a radiograph. Panoramic radiography has a little diagnostic value in the identification of periodontal disease. It is useful to obtain the overall generalized status of bone, rather than very fine or precise details. However, it can be used as a valuable adjunct to conventional diagnostic procedures. It can be recommended as a part of routine dental and periodontal assessment which captures the entire maxilla-mandibular radiographic image on a single film. However, a panoramic radiograph should not be used to replace other intraoral radiographic techniques. Semenoff et al. assessed variations between different dental radiographs for assessment of the interseptal bone crest loss on conventional and digitized periapical, bitewing, and panoramic radiographs. Comparison among them showed that a small reduction in height of the interseptal bone crest observed in panoramic radiographs should be carefully evaluated for overestimation. Moreover, several studies proposed that panoramic radiography might serve as a diagnostic aid in dental health evaluation programs [57].

### *2.3.3 Bone destruction patterns in periodontal disease*

Periodontal disease may affect the bone, altering its morphologic features in addition to reducing the vertical level of the bone height. An understanding of tissue mechanisms causing these alterations is important for effective diagnosis and effective treatment modalities.

	- Three osseous walls:
		- Proximal, buccal, and lingual walls
		- Buccal, mesial, and distal walls
		- Lingual, mesial, and distal walls

These trough-like defects are mostly seen in the interdental areas. These may exist as either shallow and wide lesions or deep and narrow ones.

	- Buccal and lingual walls (crater)
	- Buccal and proximal walls
	- Lingual and proximal walls

Two wall infrabony pockets may also occur in the interdental areas. With the buccal and lingual walls intact, but lost proximal wall, the lesion is termed as an intraosseous interproximal crater.

*Clinical Concepts and Practical Management Techniques in Dentistry*

	- Proximal wall (hemiseptum)
	- Buccal wall
	- Lingual wall

Generally in these lesions, a proximal wall is present with both buccal and lingual walls' resorbed.

• Combination:


They may be seen in a variety of combination forms and can be located on a single or multiple surface of a tooth (**Figure 1**).

II. Karn KW et al. 1983 [59]:

	- a.Crater: A crater is formed as a result of loss of alveolar bone and a portion of the contiguous supporting alveolar bone from only one surface of a tooth. They are identified by the mesial, distal, facial, or lingual tooth surface involved. Craters may be confluent if they occur on adjacent proximal surfaces, and termed as two-surface craters (affecting two tooth surfaces), named with two teeth involved.

**Figure 1.** *Showing wall defects.*

*Gender-Associated Oral and Periodontal Health Based on Retrospective Panoramic… DOI: http://dx.doi.org/10.5772/intechopen.93695*


**Figure 2.** *Showing a moat type of bone defect.*

**Figure 3.** *Showing a plane type of bone defect.*

**Figure 4.** *Showing cratered ramp type of bone defect.*

	- a.Intrabony defect: It is surrounded by bony walls on three sides and the root of tooth forming the fourth wall. The walls may be at different levels coronally forming combinations with other defects, but only the "inside" of the defect, the part that is apical to all three bony walls, is "within" bone or intrabony. They are also found in the apical region where the base of the arch is usually wider than the crest.
	- b.Hemiseptum: Periodontitis may affect one tooth and destroy septal bone adjacent to that tooth without affecting the contiguous tooth, thus leaving a hemiseptum of interalveolar bone.

**Figure 5.** *Showing ramp into a crater type of bone defect.*

*Gender-Associated Oral and Periodontal Health Based on Retrospective Panoramic… DOI: http://dx.doi.org/10.5772/intechopen.93695*


#### *2.3.3.1 Progression of periodontal disease*

The earlier viewpoint regarding the progression of periodontal disease was that bacterial plaque accumulation universally leads to gingivitis, with subsequent progressive destruction of the supporting tissues of periodontium, with continuous irreversible attachment loss and bone resorption over time. Such conclusions have mostly come from observing cross-sectional populations over long periods of time. Later In order to determine the rate, pattern, and course of bone loss, researchers longitudinally studied subjects with repeated clinical and radiological measurements of patients suffering from periodontitis. Papapanou and coworkers [61] studied over 200 subjects with full-mouth radiographic surveys taken 10 years apart. The findings revealed that the mean annual rate of bone level resorption varied by age. Subjects between the ages of 25 and 65 years exhibited between 0.07 and 0.14 mm/ year; whereas subjects over 70 years of age had a significantly higher rate of bone loss (0.28 mm). This particular investigation gave an insight into the trend of alveolar bone loss that it was continuous, slowly progressive, but with a great deal of the variable rate of progression among teeth and subjects. A similar 6-year long study in elderly Chinese subjects also revealed the individual range of bone loss varied dramatically from 0 to 0.53 mm/year [62]. Similar observations had been seen from the previous classically cited study by Löe and coworkers in Sri Lankan tea workers [63], which also reported huge differences in the rate of periodontal destruction among individuals.

Goodson and coworkers [64] challenged the prevalent belief system at that time that oral bone loss proceeded in a gradual fashion. In a series of studies, they examined the individual tooth site for progressive bone loss [65–68]. Among 22 untreated subjects with existing chronic periodontitis and pockets due to bone loss, only 15 subjects witnessed significantly deeper pockets over a time span of 1 year, whereas the other tooth sites rather showed a gain in attachment and reduction in the existing pocket depths. This investigation provided the evidence that alveolar bone destruction associated with periodontal disease was a dynamic condition and exhibited exacerbations and remissions of the disease activity over a period of time. This led to the emergence of "burst model" for periodontal disease progression pattern which had irregular bouts of the disease activity as opposed to continuous slow bone destruction over time. These classic studies utilized conventional manual probing to measure clinical attachment-levels to identify specific sites exhibiting more than 2 mm of progressive attachment loss and merely 5% of tooth sites exhibited progressive attachment loss. Another study [69] revealed 29% of the tooth sites showing progression over a 6-month period in adult patients previously diagnosed

with periodontitis, by utilizing a more sensitive electronic probe to measure attachment loss. Modeling of the data over time showed that 76% of tooth sites lost attachment consistent with linear patterns, 12% of tooth sites showed exacerbations and remissions, and 12% revealed bursts of disease activity. Since then, a lot of periodontal disease progression models have come into being based on diverse studies, for example, Socransky, Goodson 1984 [70]. (1) Continuous Models: Slow and continuous, constantly progressive rate of destruction throughout the duration of the disease. (2) Random or episodic burst model: Short bursts of destruction followed by periods of no destruction, random pattern of disease w.r.t. the tooth sites affected. (3) Asynchronous, multiple burst model: periodontal destruction occurs in bursts, around affected teeth during defined periods of life. The chronology of these bursts of disease is asynchronous for individual teeth or groups of teeth. The natural history and progression patterns of intraoral bone loss are yet not clearly and completely understood at this time [71].
