Role of collagen membrane in modified guided bone regeneration surgery using buccal punch flap approach: A retrospective and radiographical cohort study / 北京大学学报(医学版)

OBJECTIVE@#To investigate whether the placement of absorbable collagen membrane increase the stability of alveolar ridge contour after guided bone regeneration (GBR) using buccal punch flap.@*METHODS@#From June 2019 to June 2023, patients who underwent GBR using buccal punch flap simultaneously with a single implant placement in posterior region (from first premolar to second molar) were divided into coverage group, in which particular bone graft was covered by collagen membrane and non-coverage group. Cone beam CT (CBCT) was taken before surgery (T0), immediately after surgery (T1), and 3-7 months after surgery (T2), and the thickness of the buccal bone plate at different levels (0, 2, 4, and 6 mm) below the smooth-rough interface of the implant (BBT-0, -2, -4, -6) was mea-sured after superimposition of CBCT models using Mimics software.@*RESULTS@#A total of 29 patients, including 15 patients in coverage group and 14 patients in non-coverage group, were investigated in this study. At T0, T1, and T2, there was no significant difference in BBT between the two groups (P>0.05). At T1, BBT-0 was (2.50±0.90) mm in the coverage group and (2.97±1.28) mm in the non-coverage group, with corresponding BBT-2 of (3.65±1.08) mm and (3.58±1.26) mm, respectively. At T2, BBT-0 was (1.22±0.55) mm in the coverage group and (1.70±0.97) mm in the non-coverage group, with corresponding BBT-2 of (2.32±0.94) mm and (2.57±1.26) mm, respectively. From T1 to T2, there were no statistically significant differences in the absolute values [(0.47±0.54)-(1.33±0.75) mm] and percentages [(10.04%±24.81%)-(48.43%±18.32%)] of BBT change between the two groups. The thickness of new bone formation in the buccal bone plate from T0 to T2 ranged from (1.27±1.09) mm to (2.75±2.15) mm with no statistical difference between the two groups at all levels.@*CONCLUSION@#In the short term, the GBR using buccal punch flap with or without collagen membrane coverage can effectively repair the buccal implant bone defect. But collagen membrane coverage showed no additional benefit on alveolar ridge contour stability compared with non-membrane coverage.

A comparative study of two imaging techniques for the diagnosis of sagittal fracture of mandible condyle / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the relationship between fractured fragment and joint disc displacement after sagittal fracture of mandibular condyle (SFMC).</p><p><b>METHODS</b>based on CT examination, SFMC were classified into fissue, displacement and dislocation type. Based on oblique sagittal MRI examination, the displacement of joint disc was grouped into type A and type B. Abnormal superiorposterior attachment was classified into elongation and avulsion type.</p><p><b>RESULTS</b>CT exmination were taken in 26 patients with 41 SFMC. There were 5 SFMC (12%) with fissue type, 18 SFMC (44%) with displacement type and 18 SFMC (44%) with dislocation type. Both CT and MRI examination were taken in 19 patients with 32 SFMC. There were 27 (84%) SFMC with disc displacement. Five SFMC with type fissue showed no signs of disc displacement. Among 15 SFMC with type displacement, there were 3 cases with type A disc displacement and 12 cases with type B disc displacement. All the dislocated SFMC (12 cases) were type B disc displacement. In term of superiorposterior attachment figures, 4 cases (4/5) of type fissue SFMC showed normal. 14 cases (14/15) of the displacement SFMC showed elongated and all cases with dislocated SFMC showed sign of avulsion. There were 20 cases (63%) showing superior joint effusion. There were 13 cases (13/15) with displaced SFMC and 6 cases with dislocated SFMC showing joint effusion. One case with fissue SFMC showed no sign of joint effusion.</p><p><b>CONCLUSIONS</b>Joint effusion, disc displacement and abnormal superiorposterior attachment were related to the displacement of condyle which was involved with SFMC.</p>

A meta-analysis of condylar fracture treatment / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To systematically evaluate the surgical and non-surgical treatment of condylar fracture using Meta-analysis system.</p><p><b>METHODS</b>The key words: mandible, condyle, fracture and treatment/therapy were adopted to search for the objective articles from following Data-base: Medline, Embase, CCTR and CNKI. The available data were statistically dealt with by software package (RevMan 4.1).</p><p><b>RESULTS</b>In 172 associated articles, only 10 (5.8%) fulfilled the entrance criteria, involving 711 cases. A total of 307 patients underwent surgical treatment due to severely displacement or dislocation of fragment, 239 of the m (78.0%) being subcondylar fracture. A total of 404 patients received non-surgical management, 278 of them (68.7%) being lower level fracture without significant displacement. Surgical treatment outbalanced non-surgical approach in rehabilitation of occlusional relationship and an adverse outcome was noted in term of maximum mouth opening, but the re was no significant difference in postoperative joint pain.</p><p><b>CONCLUSIONS</b>Severely displaced and dislocated condylar fracture is indicated for surgical treatment.</p>

A revised scheme for LeFort classification of upper jaw fractures / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To put forward a revised scheme on LeFort classification for the upper jaw fractures.</p><p><b>METHODS</b>193 consecutive cases with the primary diagnoses of upper jaw fractures were involved in this study, for each one of which water's and CT scan were available to decide the fracture site and pattern. Data were filed in term of classification items as LeFort I, II and III fracture, as well as sagittal fracture and alveolar fracture. Statistical analysis was done to validate the meliorating thought on and revised scheme on LeFort classification.</p><p><b>RESULTS</b>It was validated that of 185 cases with upper jaw fractures only 30.81% which presented single-line fracture and 34.06% which presented multiple-line fracture were covered with LeFort classification. Additional 13.51% with single-line fracture and 21.61% with multiple-line fracture could be included when LeFort classification was extended with increase of items of sagittal fracture and alveolar fracture. Further results revealed that among total 344 sites or fracture lines included in 193 cases, 81.10% could be diagnosed fracture pattern of LeFort classification. Of 65 fracture sites presenting LeFort III type, 92.31% were concomitant with LeFort II type or LeFort I and II type, very few being alone.</p><p><b>CONCLUSIONS</b>A revised classification was proposeded that upper jaw fractures could be classified into four types as follows: (1) high horizontal fracture (corresponding to LeFort II and III type), (2) low horizontal fracture (corresponding to LeFort I type), (3) sagittal fracture (including midline and para-midline fracture) and (4) alveolar fracture.</p>