Accuracy and efficiency of a calibration approach in dynamic navigation for implant placement: An in vitro study.

Background/purpose: Computer-assisted dynamic navigation surgery could provide accurate implant placement. However, its low efficiency was always criticized by dental surgeons. The purpose of this study was to evaluate the accuracy and efficiency of a calibration approach with reflective wafers in dynamic navigation for implant placement. Materials and methods: Eighty implants were placed in the standardized polyurethane mandibular models under dynamic navigation and divided into 2 groups according to the calibration methods (n = 40). The U-shaped tube (UT) group used a prefabricated U-shaped tube embedded with radiopaque markers. The reflective wafers (RW) group used a fixation with 3 round reflective wafers as markers. Postoperative cone beam computed tomography images were obtained for implants deviation analyses. The calibration time was used to evaluate the efficiency of the 2 methods. Results: Significant differences were found in the trueness and efficiency between the 2 groups (P < 0.05). The 3D deviations at the implant platform and apex were smaller in UT group (0.89 ± 0.28 and 0.79 ± 0.30 mm, respectively) than in the RW group (0.99 ± 0.28 and 0.98 ± 0.30 mm, respectively). The angular deviation was larger in the UT group (2.16 ± 1.12°) than in the RW group (1.53 ± 0.88°). The calibration approach of RW group was more efficient than the UT group (2.05 ± 0.55 and 7.50 ± 0.71 min, respectively). Conclusion: The calibration method of RW improved the efficiency significantly and achieved equivalent trueness with UT for dynamic navigation during implant placement.

Accuracy of 3 calibration methods of computer-assisted dynamic navigation for implant placement: An in vitro study.

STATEMENT OF PROBLEM: Dynamic navigation for implant placement has been reported to be more accurate than freehand surgery. However, the accuracy of the calibration methods used for navigation in partially edentulous individuals with distal extensions remains unknown. PURPOSE: The purpose of this in vitro study on dental models was to evaluate the accuracy of 3 calibration methods of dynamic navigation for implant placement in the distal extension of partially edentulous arches. MATERIAL AND METHODS: Eleven standardized polyurethane mandibular models with distal extensions were prepared. The left first molar, second molar, and second premolar from each model (33 tooth sites) were randomly assigned to 1 of the 3 calibration methods: U-shaped tube embedded with radiopaque markers, anatomic tooth cusps, and bone markers with the random number table method. Preoperative and postoperative cone beam computed tomography images were obtained for deviation analyses. The primary outcomes were 3-dimensional (3D) deviation at the implant platform and apex and angular deviation. Differences among the test groups were analyzed by using a 1-way analysis of variance (ANOVA) and the least significant difference (LSD) post hoc test (α=.05). RESULTS: The mean ±standard deviation 3D deviations were 0.78 ±0.34, 1.86 ±0.91, and 1.44 ±0.57 mm at the implant platform and 0.79 ±0.35, 2.19 ±1.01, and 1.49 ±0.50 mm at the apex in the U-shaped tube, tooth cusp, and bone marker groups, respectively. The 3D deviations at the implant platform and apex were significantly different among the groups (P<.01). The angular deviation was 1.36 ±0.54, 2.95 ±2.07, and 2.92 ±2.45 degrees, with no significant differences among the groups (P=.092). CONCLUSIONS: In the dynamic navigation of implant placement in the distal extension of partially edentulous arches, the U-shaped tube calibration with radiopaque markers was more accurate than the anatomic tooth cusp or bone marker calibration.

FOXO1 expression in chondrocytes modulates cartilage production and removal in fracture healing.

Fracture healing is a multistage process characterized by inflammation, cartilage formation, bone deposition, and remodeling. Chondrocytes are important in producing cartilage that forms the initial anlagen for the hard callus needed to stabilize the fracture site. We examined the role of FOXO1 by selective ablation of FOXO1 in chondrocytes mediated by Col2α1 driven Cre recombinase. Experimental mice with lineage-specific FOXO1 deletion (Col2α1Cre+FOXO1L/L) and negative control littermates (Col2α1Cre-FOXO1L/L) were used for in vivo, closed fracture studies. Unexpectedly, we found that in the early phases of fracture healing, FOXO1 deletion significantly increased the amount of cartilage formed, whereas, in later periods, FOXO1 deletion led to a greater loss of cartilage. FOXO1 was functionally important as its deletion in chondrocytes led to diminished bone formation on day 22. Mechanistically, the early effects of FOXO1 deletion were linked to increased proliferation of chondrocytes through enhanced expression of cell cycle genes that promote proliferation and reduced expression of those that inhibit it and increased expression of cartilage matrix genes. At later time points experimental mice with FOXO1 deletion had greater loss of cartilage, enhanced formation of osteoclasts, increased IL-6 and reduced numbers of M2 macrophages. These results identify FOXO1 as a transcription factor that regulates chondrocyte behavior by limiting the early expansion of cartilage and preventing rapid cartilage loss at later phases.

New surgery approaches preserving entire papilla to treat isolated interdental intrabony defects: A narrative review.

OBJECTIVES: To review novel techniques of preserving the entire papilla to minimize the trauma of fragile papilla in periodontal regeneration surgeries. MATERIAL AND METHODS: Electronic databases (Pubmed) and relevant journals were searched until September 4, 2020. Randomized controlled trials, cross-sectional and cohort studies in English were included. Three novel approaches of preserving the entire papilla were applied to bone regeneration for intrabony defects, which were entire papilla preservations (EPP), nonincised papillae surgical approach (NIPSA) and modified vestibular incision subperiosteal tunnel access (M-VISTA). RESULTS: Randomized control trials of the novel preserving entire papilla techniques were rarely reported. There were only case series or cohort studies. Several papilla preservation techniques (PPT) or minimally invasiveness surgical techniques (MIST) have existed for a long time. However, these techniques still have dissection at the papilla. There were no related RCTs comparing the three novel approaches of keeping the entire papilla with PPT and MIST. All three techniques showed totally primary wound closure. Compared with PPT/MIST, EPP and NIPSA seemed to have better clinical outcomes in reducing probing depth (PD) and clinical attachment level (CAL) gain. CONCLUSIONS: EPP and NIPSA seemed to have advanced results of PD reduction and CAL gain than PPT and MIST. This is needed to be confirmed by further research.

Natural progression of periodontal diseases in Chinese villagers based on the 2018 classification.

BACKGROUND: Based on the 2018 classification, we aimed to determine the prevalence, distribution, and progression of periodontitis in the rural Chinese population without access to dental care. METHODS: In all, 404 subjects (28.7 ± 8.9 years, M:F = 182:222) were randomly enrolled in 1992 and re-called in 1996. With the new classification, the prevalence and distribution of stage, grade, and extent were characterized. Stage progression was compared with the progression of clinical attachment loss (CAL) and radiographic bone loss (RBL). RESULTS: At baseline, 94.1% villagers suffered from periodontitis, of whom 53.7% were in Stage III/IV. The prevalence of Stage III/IV increased from 18.2% in the age group of 15 to 24 years to 60.9% in 25 to 34-year-old group and 88.7% in the 35 to 44-year-old group. Significantly more Stage III/IV, generalized, and Grade C periodontitis were found in male villagers than female villagers. In 1996, the prevalence rate of periodontitis increased to 98.5%, with 80.0% in Stage III/IV. Further, 84.2% villagers presented with Grade C periodontitis based on longitudinal ΔCAL. The rate of progression (≥1 site with ΔCAL ≥3 mm) was 63.7%. Stage progression correlated significantly with CAL and RBL progression in Stage I/II, but this association was not found in Stage III/IV. Among subjects with disease progression in Stage III/IV, 90.4% shifted from localized to generalized cases. Furthermore, ceiling effects were observed in Stage III/IV. CONCLUSIONS: In villagers without access to dental care, 94.1% suffered from periodontitis, with more than half having Stage III/IV disease based on the 2018 classification. The majority cases presented with rapid periodontal progression. Although stage progression correlated significantly with CAL and RBL progression in Stage I/II, ceiling effects existed in Stage III/IV.

The Interrelationship Between Diabetes, IL-17 and Bone Loss.

PURPOSE OF REVIEW: Diabetes has a detrimental effect on bone, increasing the risk of fracture and formation of osteolytic lesions such as those seen in periodontitis. Several diabetic complications are caused by diabetes-enhanced inflammation. This review examines mechanisms by which IL-17 contributes to diabetes-enhanced periodontitis and other effects of IL-17 on bone. RECENT FINDINGS: IL-17 upregulates anti-bacterial defenses, yet its expression is also linked to a destructive host response in the periodontium. Periodontal disease is caused by bacteria that stimulate an inflammatory response. Diabetes-enhanced IL-17 increases gingival inflammation, which alters the composition of the oral microbiota to increase its pathogenicity. In addition, IL-17 can induce osteoclastogenesis by upregulation of TNF and RANKL in a number of cell types, and IL-17 has differential effects on osteoblasts and their progenitors. Increased IL-17 production caused by diabetes alters the pathogenicity of the oral microbiota and can promote periodontal bone resorption.

Natural 4-year periodontal progression of mandibular first molars in Chinese villagers based on radiographic records.

BACKGROUND: To report 4-year natural periodontal progression of mandibular first molars based on radiographic records in 15 to 44-year-old Chinese villagers. METHODS: In 1992 (N = 486) and 1996 (N = 413), panoramic radiographs were recorded. Tooth loss of mandibular first molars was calculated. Relative bone height (RBH), intrabony defect (IBD) depth, and furcation involvement (FI) were measured on 918 and 755 mandibular first molars in 1992 and 1996, respectively. The progression of the three parameters and their relationship with widened periodontal ligament space (WPDL) were analyzed. RESULTS: In 1992, of 31 lost mandibular first molars, 29 belonged to the 35- to 44-year age group. At 4-year follow-up, five of eight lost teeth belonged to the 35- to 44-year age group. RBH decreased from 83% in 1992 to 77% in 1996. RBH progression was significantly faster in the 25- to 34- and 35- to 44-year age groups than in the 15- to 24-year age group. The mean IBD depth was 2.81 ± 0.55 mm (n = 32) in 1992 and 3.70 ± 0.73 mm (n = 33) in 1996. Prevalence of FI increased from 20.8% to 27.4%. Teeth with WPDL showed greater RBH and IBD progression than those without WPDL (RBH: 12% ± 1% versus 6% ± 0.01%, P < 0.001; IBD depth: 0.31 ± 0.08 versus 0.01 ± 0.00 mm, P <0.001). FI-area progression in teeth with WPDL showed a trend of greater expansion than in those without WPDL (0.92 ± 0.18 versus 0.56 ± 0.11 mm2 , P = 0.051). CONCLUSIONS: Tooth loss mainly occurred in the 35- to 44-year age group. RBH progression was faster in the 25- to 44-year age group. WPDL was associated with progression of RBH, IBDs, and FI.

A 4-year prospective study of the progression of periodontal disease in a rural Chinese population.

OBJECTIVES: The natural progression of periodontitis in the Chinese population is not well researched. We investigated the progression of periodontal disease over 4 years in 15-44-year-old Chinese villagers with no access to regular dental care. METHODS: In 1992, 486 villagers were enrolled, and in 1996, 413 villagers were re-examined. Probing depth (PD) and clinical attachment level (CAL) were examined at six sites per tooth. Sites with ΔCAL ≥3 mm were defined as active sites. Cross-sectional and longitudinal analyses were performed using means and percentile plots. RESULTS: The mean CAL increased by 0.26 mm over 4 years. The incidence of periodontitis (at least one site with CAL ≥3 mm) was 8%. The incidence of periodontitis among those with no periodontal disease at baseline was 44.9%. Seventy-eight percent of the subjects had at least one active site. In the 15-24-year group, 244 of 401 active sites had gingival recession, while only 51 active sites had both gingival recession and deeper pockets. In the 25-34-year and 35-44-year groups, almost one-third of the active sites (329/1087) and more than one-third of the active sites (580/1312) respectively had a combination of gingival recession and deeper pockets. CONCLUSIONS: In this study, we demonstrated that in Chinese population without regular dental care, both the initiation of periodontitis and progression of previously existed periodontitis contributed to the natural progression of periodontitis and periodontal pocketing played a greater role with age increasing. CLINICAL SIGNIFICANCE: This rare study reports the natural progression of periodontal disease in a group of Chinese villagers (15-44 years) with virtually no access to regular dental care.