Parathyroid hormone (1-34) compensates the negative effect of smoking around implants.

OBJECTIVES: This study aimed to investigate the effect of Recombinant Human Parathyroid Hormone (PTH 1-34) on attenuating the influence of cigarette smoke on bone around titanium implants. MATERIAL AND METHODS: Forty-eight female Wistar rats were used. At the beginning of the study, 15 animals were randomly assigned to Group 1 (control) and received subcutaneous injections of saline solution, three-times/week, after implant placement. The other animals received intermittent cigarette smoke inhalation (CSI), 60 days prior and 60 days after implant placement ( Al 2 O 3 -blasted titanium implants - 4.0 × 2.2 mm). After surgery, these animals were randomly assigned to: Group 2 - subcutaneous injections of saline solution, three-times/week (n = 16) and Group 3 - intermittent doses of PTH (1-34) (40 µg/Kg), three-times/week (n = 17). Animals were sacrificed 60 days after surgery, and degree of bone-to-implant contact (BIC), bone area (BA) within the limits of the threads and proportion of mineralized tissue (PMT) adjacent to the implants (500 µm wide zone) were separately obtained in cortical and cancellous bone. RESULTS: Data analysis confirmed that CSI negatively affects bone around implants, as observed for BIC in cortical zone (Cohen's d (d) = -1.26) and for PMT in both zones (d = -6.09 and d = -4.46 for cortical and cancellous zones, respectively). In addition, in the presence of CSI, PTH (1-34) promoted the highest BIC in both regions and BA and PMT in cancellous bone (P < 0.05). The histometric parameter that was not influenced by both PTH and CSI (1-34) was BA in cortical bone (P > 0.05). CONCLUSION: In the presence of cigarette smoke, a factor related to poor bone healing and low bone density, PTH (1-34) increased bone volume around implants.

Measuring periodontal biologic distances: Transperiodontal vs transsurgical probing.

OBJECTIVE: Crown-lengthening surgeries are widely indicated in dental practice and the proper measurement of biological distances is imperative for accurate surgical, prosthetic or restorative planning. However, few clinical studies have evaluated the methods for measuring these distances. The aim of this study was to compare the transperiodontal (before incision/BI: immediately before the intrasulcular incision) and transsurgical (after incision/AI: immediately after mucoperiosteal flap reflection) probing methods for measuring the biological distance. MATERIALS AND METHODS: Data from a previous randomized and controlled clinical trial were subjected to a secondary analysis, which included nine patients (26 ± 5 years), with a total of 18 teeth requiring restorative treatment. A single calibrated examiner measured the distances (in millimetres) between the cervical walls of the caries/cavity preparation and the bone crest. RESULTS: Absolute agreement between the distances measured by the BI and AI methods was 88.88%. Mean distances by BI (1.44 ± 0.51 mm; range = 1-2 mm) and AI (1.55 ± 0.61 mm; range = 1-3 mm) showed no significant differences. CONCLUSIONS: Transperiodontal probing appears to be suitable for the measurement of biological distances and may be used as an important tool for surgical planning.

Response to Proximal Restorations Placed Either Subgingivally or Following Crown Lengthening in Patients with No History of Periodontal Disease.

The purpose of this study was to compare the impact of resin restorations placed supragingivally or impinging periodontal biologic width (PBW). Ten patients (aged 19 to 35 years) with at least two contralateral teeth (premolars and molars) in need of proximal subgingival restorations participated. Test group (TG) (impingement of PBW with transsurgical restorations) and control croup (CG) (supragingival restorations after crown lengthening) were randomly assigned. Visible plaque (VP), bleeding on probing (BOP), periodontal probing depth (PPD), and clinical attachment loss (CAL) were evaluated at baseline and at 45, 90, and 180 days, and by transperiodontal probing at baseline and 180 days. Generalized estimating equations, Wald test, and t test were used (P ≤ .05). VP and BOP were reduced and maintained at low levels (less than 10% from day 45 on). PPD initially reduced in the TG. At day 180, no intra- or intergroup differences were observed (P > .05). CAL was higher in the CG after surgery (P < .05) and remained stable for both groups throughout the study. In conclusion, proximal bonded restorations infringing on the PBW may not require clinical crown lengthening.