Simultaneous GBR and GTR in the posterior mandible area

By Dr Cheng-Hsiang Hsu

A 58-year-old male patient had lost his lower-right first molar one month ago. It was extracted due to severe mobile and discomfort. He was told that second premolar was to be taken to restore the posterior dentition with dental implants. He came to my clinic for the second opinion.

The probing depths from mesial to distal were 3,2,3mm on the buccal surface and 3,3,5mm on the lingual surface of the second premolar. A probing depth of 7mm at the middle site of the posterior surface was also found. No mobility of teeth was found at this area although the attrition of buccal cusp of the second premolar was found. No other symptoms and signs of inflammation was noted.

The periapical films (Fig. 1) show the severe destruction of the supporting bone at the distal side of the second premolar. The intact mesial bony support of this tooth was also found.

According to the clinical information list, the destruction of the alveolar process should be associated with the missing first molar, and the prognosis of the second premolar would be fair.

Surgical procedure

The upper left corner of Fig. 2 shows the intact buccal wall and the destructed bone of distal side of the second premolar.

After implant placement some rough surface and threads were exposed without bony support, as shown in the upper-right corner of Fig. 2. The most apical level of the bony destruction was about apical third-deep from the second premolar.

From the occlusal view, in lower left of Fig. 2, the lingual bony wall was not totally damaged, resulting in the two-wall defect within the bony architecture. This was a good environment for the guided bone regeneration of the newly placed implant and guided tissue regeneration of the second premolar.

The buccal and lingual surface of the bony support of the 2nd premolar were not damaged, as observed in the lower right of Fig. 2, but the root surface was exposed in the middle of the distal side, creating the V-shape of the periodontal destruction.

The defect was filled with 100% puros allograft and completely covered with Biomed collagen membrane. The membrane was shaped as a saddle for complete coverage and fully seated over the ridge. Guided bone regeneration and guided tissue regeneration were performed at the same surgery and the wound was closed by 4-0 Vicryl sutures (Fig. 3).


The six-month healing process went smoothly and no other symptoms were noted. The periapical films (Fig. 4) showed the radio-opaque area between the second premolar and the dental implant.

After six months, healing the regenerated bone filled the defect between the second premolar and dental implant. No remaining bone particles were seen. All rough surface was fully covered by the alveolar bone without exposed threads.

The clinical photos and periapical films (Fig. 4-7) showed the differences before and after the treatment. The alveolar bone was regenerated. The patient accepted another implant and the regenerated bone was still in good condition five years after the treatment.

Published in Dental Asia March/April 2022 issue.

About the author

Dr Hsu received his BDS degree from Taipei Medical University (Taipei, Taiwan) in 2000 and MS degree from National Defense Medical College (Taipei, Taiwan) in 2004. He currently teaches periodontology and implant dentistry in the undergraduate and graduate program at National Defense Medical College, and was appointed head of dental department at E.C.K. hospital (2010-2012) and Taiwan Adventist’s Hospital (2014-2017). Dr Hsu was the President of Taiwan Academy of Osseointegration from 2016 to 2018 and the president of TMU Dental Taipei Alumni Association from 2018 to 2020. He is also the director of Taipei dental associates from 2018 to now. He has had his own private practice since 2018 in Taipei, Taiwan.