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JADA Specialty Scan - Radiology
Periodontics - A Quarterly Newsletter on Dental SpecialtiesJADA Specialty Scan

Extraction of mandibular third molars and periodontal effect on adjacent second molars — an investigation

Deciding whether to extract an asymptomatic mandibular third molar (M3) can be challenging for clinicians. Whereas some research shows surgical extraction can result in potential periodontal complications distal to the adjacent second molar (M2), other studies demonstrated spontaneous wound healing and attachment gains for these teeth after the extraction of M3. Furthermore, some longitudinal studies have shown that outcomes are age dependent, while others have found additional factors, such as the type of impaction and periodontal baseline, to be primary influences on periodontal healing following the extraction of M3.

To explore, researchers in Germany recruited 78 patients (49 female and 29 male) between June and October 2014 in a younger patient population (mean age [standard deviation], 16.0 [2.0] years). Their study was published online February 4, 2016, in Journal of Clinical Periodontology. They recorded plaque and gingival indexes both before and six months after surgery. They classified M3s as either fully impacted within the bone or fully covered by oral mucosa. All teeth were extracted for orthodontic reasons.
Ultimately, 58 teeth were submucosal and 20 were fully impacted. In 70 patients, both mandibular M3s were extracted. In eight patients, only one side of the jaw received surgery.

Scientists found a statistically significant decrease in both probing pocket depths (PPD) and probing attachment levels (PAL) from baseline to six months in both groups of teeth: those with preoperative probing depths of less than 4 millimeters (considered healthy) and for the distolingual and distobuccal sites in those with probing depths of 4 mm or more (considered diseased).

Results showed that males experienced a greater PPD reduction than females, although this finding was not statistically significant and the use of different suture materials had no statistically significant effect on PPD and PAL changes. However, the type of impaction — submucosal or fully impacted — had a significant effect on PPD but not on PAL.

An analysis of the influence of other possible cofactors on changes in PPD and PAL level in the study showed an association with the type of impaction of the M3. “It was shown that, if the coronal bone lamella above the (impacted) tooth was still in place, there were smaller postoperative changes in PPD and PAL levels,” the authors reported.

“Looking only at ‘pathological’ sites with on average preoperative probing depths ≥ 4 mm, removal of asymptomatic M3 at a young age may have a beneficial effect on the periodontal conditions on the distal part of M2 from a purely periodontal point of view,” authors concluded.

They advised taking into account the risk of intraoperative complications when periodontal considerations alone are driving the clinical decision to extract such teeth in the examined age group.

Read the original article.


Consulting Editor: Tapan Koticha, BDS
Diplomate, American Board of Periodontology
Assistant Professor, Department of Periodontics
Clinical Director, Graduate Periodontics
University of Oklahoma Health Sciences Center, College of Dentistry


Extraction of mandibular third molars and periodontal effect on adjacent second molars — a systematic review and meta-analysis

Although extraction of impacted third molars is one of the most common surgical interventions in dentistry, the optimal management of impacted mandibular third molars (M3s) continues to defy clinicians.
M3s have higher impaction prevalence than maxillary third molars, and their extraction has long been associated with the risk of developing persistent or new periodontal defects of the mandibular second molar (M2).

Different treatment strategies have been proposed to reduce the risk of developing periodontal defects. Researchers publishing in the March 2016 issue of Journal of Periodontology conducted a search to review the best evidence on the effect of M3 extractions on periodontal health of M2, establish a ranking for treatment options and identify the best approach in terms of clinical attachment level (CAL) gain and probing depth reduction at the distal surface of the adjacent M2.

Sixteen randomized controlled trials (RCTs), 10 of which were eligible for meta-analysis, were included in the review. In selected studies, participants were patients with fully developed M3s and a clinical diagnosis of unilateral or bilateral M3 impaction requiring extraction. Outcomes considered from baseline to the follow-up visit were the change in CAL, change in probing depth and patient subjective outcomes such as pain. Financial aspects and chair time were also explored to evaluate M3 extraction interventions.
Authors’ deduction suggested that guided tissue regeneration with resorbable (GTRr) membrane and nonresorbable membrane, and GTRr with anorganic xenograft had the highest probability of being the best treatments, ranking the highest for CAL gain and probing depth reduction.

The researchers noted that their systematic review classified most of the RCTs at moderate risk of bias and the quality of evidence very low to moderate. They called for additional research based on well-designed RCTs to provide reliable estimates of periodontal healing and to address other patient-related aspects “because these factors have been poorly investigated so far and might play a significant role in the decision-making process,” they said.

Among the conclusions they reported, they found that GTR therapies with nonresorbable and resorbable membranes and their grafting-combined therapies achieved some additional clinical benefit compared with standard nonregenerative/nongrafting procedures in terms of CAL gains and probing depth reduction. “However, the overall low quality of evidence suggests a low degree of confidence and certainty in treatment effects,” they said.

Read the original article.


Registration opens in May: AAP Annual Meeting heads to San Diego this September
The 102nd Annual Meeting of the American Academy of Periodontology will be held Sept. 10-13 at the San Diego Convention Center. This meeting will be held in collaboration with the Japanese Society of Periodontology and the Japanese Academy of Clinical Periodontology.

Registration opens May. For more information, visit or e-mail


Comparing tissue destruction in two common diseases


Periodontitis and peri-implantitis are both caused by bacterial infection, yet the two diseases differ pathologically. In fact, studies using animal models have demonstrated that peri-implantitis advances much faster than periodontitis.

Although differences have been discussed in the literature, scientists in Japan found that most of the studies used ligature models to induce inflammation in the soft tissue and bone surrounding the tooth or implant, making it difficult to compare inflammation occurring in natural tooth and litigated implant models. “For example, destruction of peri-implant tissues induced by ligature continued progressing for six months after ligature removal while periodontal destruction stopped immediately after,” they said, highlighting previous research.

Consequently, they conducted their own study to compare tissue destruction in periodontitis and peri-implantitis by applying a topical antigen in the gingival sulcus of immunized rats. The research was based on their previous experimental periodontitis model wherein they found that the formation of immune complexes accelerates site-specific loss of attachment and alveolar bone resorption. The experimental peri-implantitis model used in this study allowed them to examine the onset and progression of the disease by changing the concentration of stimuli, duration of the experiment or both.

They found that the severity of tissue destruction in the peri-implant tissue was clearly greater than that in the periodontal tissue.

“Patients with a history of periodontitis are thought to be already immunized with periodontopathic bacteria or their components and, therefore, are more likely to develop periodontal destruction because immune complexes are easily formed in the gingival tissue,” researchers suggested. “Implantation in such patients would have the risk of early recurrence and severe progression of peri-implantitis by the same mechanism seen when accumulated plaque acts as an antigen.”

They advised that although dental implants are one of the most important treatment options for patients with periodontitis, such knowledge is necessary to achieve appropriate periodontal treatment before initiating implant therapy. The study was published online ahead of print January 25, 2016, in Clinical Oral Implants Research.

Read the original article.


Cement retention and peri-implant disease

Despite a growing number of cohort studies and case series suggesting an association of excess cement with peri-implant mucosal inflammation and peri-implant attachment loss, new research finds no association between type of prosthesis retention and peri-implant diseases.

Instead, scientists publishing in the March 2016 issue of Journal of Periodontology supported the use of astute diagnostic methods for timely detection of residual cement in combination with meticulous techniques to minimize the risk of producing such residual cement.

In examining the association between type of retention (cement versus screw restorations) in 394 implants in 135 patients with an average follow-up of 5.5 years, they analyzed participants’ demographic characteristics and smoking status, in addition to clinical and radiographic data.

“Current findings point out that, when appropriate selection and removal of cement is performed, cement retention is not a risk indicator for peri-implant diseases,” researchers said among their conclusions. “The results presented are not supposed to underestimate the issue of the cement excess and its negative effect on peri-implant tissue health, but rather show that by following the appropriate treatment protocol and an evidence-based approach to materials selection, clinicians can limit cement excess and consequently avoid cement-associated biologic complications.”

The authors emphasized the importance of certain factors such as type of cement and cementation technique used, location of restoration margins and expertise level of operators.

Patient recruitment and data collection were performed at the Department of Prosthetic Dentistry of the Dresden University of Technology, Dresden Germany.

Read the original article.


New CDC data estimate periodontal disease prevalence at local levels

New data from the Centers for Disease Control and Prevention approximate high incidence of periodontal disease among southeastern and southwestern states, including areas along the Mississippi Delta and the U.S.-Mexico border. The areas estimated to have the greatest concentration of periodontitis directly correlate with regions that also see high incidence of cardiovascular disease and diabetes, systemic conditions often associated with periodontitis.

Additionally, the findings — published online ahead of print February 4 in Journal of Dental Research — are in line with early CDC reports that periodontitis disproportionately affects ethnic minorities, tobacco users, those of lower socioeconomic status and those in areas with sparse access to dental care.

The findings serve as a call to action for all dental professionals to educate their patients about the risk of developing periodontal disease and thoroughly assess every patient for the disease with annual comprehensive periodontal evaluations. Check out the American Academy of Periodontology’s Comprehensive Periodontal Therapy: A Statement by the American Academy of Periodontology and click here to learn more about the latest prevalence estimates. 


How many of your patients lie about flossing? Study says 27 percent

A national survey administered by the American Academy of Periodontology found that 27 percent of American adults lie to their dentists about how often they floss their teeth. The survey also found that instead of flossing, 18 percent would prefer to wash dishes, 14 percent would rather wait in a long line, another 14 percent would choose to clean the toilet and 9 percent would prefer to sit in gridlocked traffic. Learn more about Americans’ relationships with their gums by clicking here.


ADA periodontal disease poster speaks volumes

Periodontal disease seems more real to patients when they can clearly see the damage caused. The ADA’s vividly illustrated wall chart shows the damaging effects of periodontal disease at a glance.
Bone loss radiographs combined with “stages of periodontal disease” photos tell the story. Warning signs of disease are listed, and probing illustrations show diagnosis. To order, call 1-800-947-4746 or go to Readers who use the code 16404E before April 29 can save 15 percent on all ADA Catalog products.


Available for download: clinical and scientific papers from the AAP
The American Academy of Periodontology has developed a suite of resources to be used as guidelines for dentists dealing with periodontal health issues. These resources include:

  • Disease classifications
  • AAP-commissioned reviews
  • Parameters of care
  • Position papers
  • Consensus papers/clinical recommendations
  • Academy statements

View and download these materials by clicking here.


What is Specialty Scan?

This is one in a series of quarterly newsletters updating dentists on selected specialties in dentistry. Information presented is aggregated and summarized from previously published materials, each item attributed to its publication of origin. This issue of JADA Specialty Scan focuses on Periodontics, the second in the series on this topic for 2016. Other Specialty Scan issues are devoted to endodontics, oral pathology, oral and maxillofacial radiology, orthodontics and prosthodontics. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. We welcome feedback on this and all Specialty Scan issues.

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