The present study used a non-resorbable, alloplastic material (PTG) in intra-osseous defects as a reconstructed material. This technique attempts to fill the osseous defect and not solve the disease. With regard to defect fill, it is very important to keep in mind that a non-resorbable graft material such as PTG will be left unresorbed. In this study, PTG graft particles were easily seen on radiographs 7 years after therapy. Many of the particles were however scattered in the tissues around the defect. Due to the radiopaque appearance of PTG, they were easily recognized. One must in this context remember that other non-resorbable bone substitutes may also have a similar outcome but will not be as easily found and thus mistakenly considered resorbed.

Comparing the radiographs after 7 years, the extent of granules left in the osseous defects had a great variety, and two cases provided extensive loss of material. This may be explained by defect configuration, recognized at the time of surgery [28]. The inclusion of one to two walled defects may explain the absence of PTG at some sites. The PTG granules in the osseous defects may not have been well integrated with the bone, or some granules were left encapsulated in the connective tissue. Smoking habits may also have affected the reconstructive treatment [29] due to the participants who were smokers or former smokers.

None of the included subjects reported an experience of adverse effects, such as pain, discoloration of the surrounding mucosa or loose particles in conjunction with the grafting material. This is in agreement with a multicentre trial [15].

The clinical examination did not reveal any differences between the reconstructed versus non-reconstructed osseous defects related to signs of inflammation or plaque accumulations.

The present study confirmed the results from the previous study by Wohlfahrt et al. [12] and Jepsen et al. [15]. Both these publications show non-significant difference between groups in clinical parameters.