A study (in press) appears in the International Journal of Oral and Maxillofacial Surgery (2012) titled “Early extraction: a silver bullet to avoid nerve injury in lower third molar removal?” by Q. B. Zhang and Z. Q. Zhang.
At the beginning of the article the authors discuss how lower third molars show the highest incidence of impaction and are responsible for pathology such as pericoronitis, periodontitis, pain, cysts, tumors, and second molar-tooth crown resorption. I have discussed the risks of keeping wisdom teeth in over here http://www.teethremoval.com/risks_of_keeping_wisdom_teeth.html
The authors also discuss the complications associated with removal of third molars which I have elaborated on in great detail here http://www.teethremoval.com/complications.html.
In this study two groups of patients from China were grouped: A) those less than 23 and with immature teeth, and B) those greater than 23 and with mature teeth.
Group A consisted of 518 patients with 808 lower third molars extracted and group B consisted of 532 patients with 810 lower third molars extracted.
In Group A 20 of the 808 lower wisdom teeth were associated with complications (2.48%) with all of them temporary.
In Group B 81 of the 810 lower wisdom teeth were associated with complications (10%) with two cases of permanent inferior alveolar nerve numbness.
In the discussion the authors state:
“In this study, the incidences of overall complications and nerve injury in the early removal group were much lower than those in group B [the late removal group], in particular the incidence of nerve injury following early dental extraction (0%) is significantly lower than that reported in other studies,11 while the incidence in group B was consistent with previous reports.”
Near the end of the article the authors suggest a few reasons for removal of third molars. The authors state:
“The main criterion is advice from the orthodontist to prevent relapse after orthodontics. In this region of the world, fixed orthodontics usually begins at 10 years of age. It is difficult to achieve a perfect orthodontic result without tooth extraction, so generally, orthodontists chose the first premolars and the third molars for extraction to make room for teeth movement.”
The authors go on to state:
“In young patients, alveolar bone is more flexible, which avoids fractures, and it is much safer to perform surgical extraction in the young than in older people because of the odds of systemic diseases (high blood pressure, cardiovascular disease, diabetes). The recovery period will also be shorter and the prognosis will be better.”
Like other studies I have referred to here http://www.teethremoval.com/wisdomteeth.html other evidence from other studies also tends to show an increase in age is associated with an increase in a complication occuring after wisdom teeth removal and increased difficulty of extraction.