Three-dimensional assessment of the anterior and inferior loop of the inferior alveolar nerve using computed tomography images in patients with and without mandibular asymmetry.

BACKGROUND: The purpose of this study was to investigate the differences in configuration and dimensions of the anterior loop of the inferior alveolar nerve (ALIAN) in patients with and without mandibular asymmetry. METHOD: Preoperative computed tomography images of patients who had undergone orthognathic surgery from January 2016 to December 2018 at a single institution were analyzed. Subjects were classified into two groups as "Asymmetry group" and "Symmetry group". The distance from the most anterior and most inferior points of the ALIAN (IANant and IANinf) to the vertical and horizontal reference planes were measured (dAnt and dInf). The distance from IANant and IANinf to the mental foramen were also calculated (dAnt_MF and dInf_MF). The length of the mandibular body and symphysis area were measured. All measurements were analyzed using 3D analysis software. RESULTS: There were 57 total eligible subjects. In the Asymmetry group, dAnt and dAnt_MF on the non-deviated side were significantly longer than the deviated side (p < 0.001). dInf_MF on the non-deviated side was also significantly longer than the deviated side (p = 0.001). Mandibular body length was significantly longer on the non-deviated side (p < 0.001). There was no significant difference in length in the symphysis area (p = 0.623). In the Symmetry group, there was no difference between the left and right sides for all variables. CONCLUSION: In asymmetric patients, there is a difference tendency in the ALIAN between the deviated and non-deviated sides. In patients with mandibular asymmetry, this should be considered during surgery in the anterior mandible.

Is There a Difference in Condyle Position Changing Pattern Between Deviated and Non-Deviated Sides After Intraoral Vertical Ramus Osteotomy in Facial Asymmetry?

PURPOSE: The position changing pattern of the condyles after intraoral vertical ramus osteotomy (IVRO) on the deviated and non-deviated sides is not clearly known. This study was conducted to evaluate the changes in condylar position after IVRO in patients with facial asymmetry and to compare the deviated and non-deviated sides using computed tomography imaging. MATERIALS AND METHODS: This retrospective cohort study investigated patients with a diagnosis of mandibular prognathism with facial asymmetry who had undergone bilateral IVRO with Le Fort I osteotomy. Condylar positions were recorded on the non-deviated and deviated sides in the midaxial, midsagittal, and coronal planes at 3 time points using 3-dimensional analysis software: preoperatively (T1), at 6 months postoperatively (T2), and at 12 months postoperatively (T3). Linear and angular changes in condyle position were measured and analyzed between T1, T2, and T3. Reliability and comparative analyses were conducted. RESULTS: Thirty-two patients were involved in this study. At T2, the most superior point of the condyle moved to 1.15 ± 0.24 mm (inferiorly) and 0.88 ± 0.23 mm (anteriorly) on the deviated side (P = .0002 and P = .0005, respectively) and to 0.99 ± 0.25 mm (inferiorly) and 1.08 ± 0.34 mm (anteriorly) on the non-deviated side, showing significant differences (P < .0001 and P = .0007, respectively) compared with T1. The condyle position showed a tendency to recover to its original position by T3. However, there were no statistically significant differences between T2 and T3 (P > .05). Furthermore, there were no statistically significant differences between the deviated and non-deviated sides over the entire follow-up period (P > .05). CONCLUSIONS: The condyles did not completely recover to their preoperative positions until 12 months postoperatively. There was no significant difference between the deviated and non-deviated sides in mandibular prognathism with facial asymmetry.

Effects of thread size in the implant neck area on peri-implant hard and soft tissues: an animal study.

OBJECTIVES: The aim of this animal study was to examine the effects of thread size in the implant neck area on peri-implant tissues in terms of BIC and hard- and soft-tissue dimensions. MATERIALS AND METHODS: Six Beagle dogs received experimental implants in the mandible 3 month after the removal of premolars and first molars (P2, P3, P4, and M1). Two different types of implants were installed in each animal: Anyone microthread(®) as Group 1 and Anyone(®) as Group 2. Resonance frequency test, intraoral radiography, micro-CT, and histomorphometry were used to evaluate peri-implant tissue after implantation periods of 4 and 8 weeks. RESULTS: No remarkable complication was observed during the healing period in either group. Resonance frequency testing revealed no significant difference between groups. In radiographic evaluation, Group 2 showed more bone loss than Group 1. However, this difference was not statistically significant. In the micro-CT analysis, BIC and BIV values and soft-tissue height were not significant in both groups. Histological analysis revealed no significant difference in BIC ratio, bone density, or bone loss between groups. However, soft-tissue height was significantly greater in Group 2 than in Group 1 (P = 0.0004). CONCLUSION: No difference in peri-implant hard or soft tissues was observed according to thread size in the implant neck area.

The effects of off-axial loading on periimplant marginal bone loss in a single implant.

STATEMENT OF PROBLEM: A discrepancy between crown width and implant width may contribute to potential bending overload. PURPOSE: The purpose of this study was to evaluate the influence of the crown width-fixture width ratio on crestal bone loss around single dental implants placed in the first molar area. MATERIAL AND METHODS: Seventy-six participants (37 men and 39 women; age range, 25-83 years; mean age [standard deviation], 56.3 ±10.6 years) were selected from individuals who were treated with single tooth implants between May 2004 and December 2009 at the Department of Periodontology, Gangnam Severance Dental Hospital. The marginal bone-level change and gingival parameters (modified plaque index and modified sulcus bleeding index) of the periimplant soft tissue were assessed 1 year after functional loading. The perpendicular distances from the vertical axis of each fixture to the most distal aspect of the crown and most mesial aspect of the crown were measured in the periapical radiographic view. RESULTS: No statistically significant relationship was found between crown width-fixture width ratio and the 1-year bone-level change (Pearson correlation, P=.06; Spearman rank test, P=.14). No statistically significant differences in marginal bone-level change were found between axial and nonaxial loading implants (2 independent samples t test; P=.19). The bone-level change for the surface adjacent and distant to the cantilever was not statistically significant (paired t test; P=.10). CONCLUSION: From this study, it may be concluded that off-axial loading that results from a high crown width-fixture width ratio does not increase the risk for periimplant marginal bone loss after 1-year functional loading.

Change in masticatory ability with the implant restoration of second molars.

STATEMENT OF PROBLEM: Controversy exists as to whether missing second molars should be replaced to restore masticatory ability. PURPOSE: The purpose of this study was to analyze the alteration in masticatory ability associated with the implant restoration of the second molar; the subjective effect of implant treatment on the participant was also assessed. MATERIAL AND METHODS: Twenty-one individuals (13 men and 8 women) participated. Masticatory ability was recorded before the cementation of implant-supported single crowns, immediately after cementation, and 1 month after cementation. The occlusal load (Pa), the load-bearing contact area (mm(2)), and the maximum occlusal force (N) were calculated. A subjective evaluation of masticatory ability was conducted before treatment and 1 month after treatment through the use of a questionnaire to evaluate chewing difficulties and global satisfaction with treatment. The Wilcoxon signed rank test was used to analyze the difference in scores. RESULTS: The load-bearing contact area, maximum occlusal force, and participant satisfaction were found to increase significantly 1 month after the cementation of implant-supported single crowns. The restoration of the second molar with an implant increased both objective masticatory ability and subjective satisfaction 1 month after cementation of the implant-supported single crowns. CONCLUSIONS: Patients presenting with a missing second molar may benefit from replacement with implant-supported crowns. Longer study periods and larger sample populations are needed to obtain more definitive results.

Effect of thread size on the implant neck area: preliminary results at 1 year of function.

OBJECTIVES: To evaluate and compare the effect of the coronal thread size on the marginal bone loss around the fixtures, when both implants were provided with threads to the top of fixture. MATERIALS AND METHODS: Two groups of implants, one with a macro-thread to the top of the fixture (A) and the other with a micro-thread to the top of the fixture (B), were placed adjacent to each other in the partially edentulous areas of 20 patients. Bone loss around each implant was analyzed after 1 year of functional loading. The bone losses after loading were compared using Wilcoxon's signed-rank test. RESULTS: The mean marginal bone losses (A, 0.154 ± 0.144 mm; B, 0.125 ± 0.136 mm) were not statistically significant between the two groups (P = 0.669). CONCLUSIONS: There was no significant difference between implant with macro- and micro-neck thread in terms of marginal bone loss after 1 year of loading.

Effect of conical configuration of fixture on the maintenance of marginal bone level: preliminary results at 1 year of function.

OBJECTIVES: To evaluate and to compare the effect of the conical neck design on marginal bone loss around the fixtures, when both implants were provided with micro-threads to the top of the fixture. MATERIALS AND METHODS: Two types of implant, one with a straight shape (S) and the other with a conical neck design (C) provided with a retentive element to the top of the fixture, were placed adjacent to each other in the partially edentulous areas of 12 patients. Bone loss around each implant was analyzed after 1 year of functional loading. The bone losses after loading were compared using Wilcoxon's signed-rank test. RESULTS: The mean marginal bone losses (S, 0.05 + or - 0.09 mm; C, 0.07 + or - 0.14 mm) were not statistically significant between the two groups (P=0.578). CONCLUSIONS: There was no significant difference between conical and straight neck implants in terms of marginal bone loss after 1 year of loading.

Influence of early cover screw exposure on crestal bone loss around implants: intraindividual comparison of bone level at exposed and non-exposed implants.

BACKGROUND: The objective of this study was to evaluate the influence of early exposure of the cover screw on crestal bone loss around implants. METHODS: The study population consisted of 19 patients who were treated with dental implants placed using a two-stage surgical protocol and had early exposed and non-exposed implants (20 early exposed and 20 non-exposed implants). The crestal bone loss at exposed and non-exposed implants in each patient was evaluated with a periapical radiograph taken at the first surgery and at suprastructure insertion using a computerized image-analysis system. The bone loss was compared using the Wilcoxon signed-rank test. RESULTS: The mean crestal bone loss at exposed implants was 0.40 +/- 0.53 mm, and it was 0.18 +/- 0.26 mm at non-exposed implants. The Wilcoxon signed-rank test revealed a statistically significant difference in crestal bone loss between exposed and non-exposed implants in the same patient (P = 0.02). CONCLUSIONS: The early exposure of the cover screw that results in breakdown of the mucosal seal seems to accelerate early peri-implant crestal bone loss. Periodic follow-up after the first surgery may be critical for minimizing the influence of early exposure.

Influence of the tooth- and implant-side marginal bone level on the interproximal papilla dimension in a single implant with a microthread, conical seal, and platform-switched design.

BACKGROUND: The purpose of the present study was to investigate whether bone level on the tooth side was the single dominant factor on the dimension of an interproximal papilla around single-tooth restorations made on a microthread, conical seal, and platform-switched design implant. METHODS: Periapical radiographs were taken of 17 patients, each of whom was treated with a single implant. The bone levels on the tooth (Dt) and implant (Di) sides were recorded. The dimension of the papilla (Ph) was measured as the shortest distance from the top of the papilla to the crestal bone. The marginal bone levels of the implants were also measured. The Pearson correlation coefficient was used to correlate the variables, and a regression analysis was used to determine whether Di or Dt had a significant (P <0.05) influence on Ph. RESULTS: A positive correlation existed between Ph and Di (r = 0.413; P = 0.023) and between Ph and Dt (r = 0.830; P <0.0001). However, only Dt had a significant influence on Ph. CONCLUSION: Dt is the dominant factor that influences the interproximal soft tissue dimension between a natural tooth and a single implant with a microthread, conical seal, and platform-switched design.

Comparison of interproximal soft tissue height for single implants and contra-lateral natural teeth.

OBJECTIVE: To compare the interproximal soft tissue dimensions adjacent to single implant restorations in the premolar-molar position with those adjacent to the contra-lateral natural teeth. MATERIAL AND METHODS: Twenty-five patients with a single-tooth implant in premolar-molar position and healthy contra-lateral teeth were enrolled in this retrospective cross-sectional study. The reason for the extraction was periodontitis. Radiographs were used to measure the shortest distance from the tip of the papilla to the crestal bone in single implants and contra-lateral teeth. A Wilcoxon's signed-ranks test was used to examine the differences between the interproximal soft tissue dimensions adjacent to the single-tooth implant restorations (IS-STI) from those of the contra-lateral natural teeth (IS-NT). RESULTS: We found no significant difference between the mesial IS-STI and the mesial IS-NT (3.28+/-0.83/3.31+/-0.62; P=0.861), or between the distal IS-STI and the distal IS-NT (3.09+/-0.72/3.3+/-0.63; P=0.263). CONCLUSIONS: The interproximal soft tissue height adjacent to single-implant-supported restorations in the premolar-molar position is similar to that adjacent to the contra-lateral natural teeth.

Three-dimensional computed tomography evaluation of craniofacial characteristics according to lateral deviation of chin.

BACKGROUND: The relationship between the lateral deviation of chin and the upper and middle facial third asymmetry is still controversial. The purpose of this study is to evaluate the correlation of upper and middle facial third asymmetry with lateral deviation of chin using 3-dimensional computed tomography. The study was conducted on patients who underwent orthognathic surgery from January 2016 to August 2017. A total of 40 patients were included in this retrospective study. A spiral scanner was used to obtain the 3-dimensional computed tomography scans. The landmarks were assigned on the reconstructed 3-dimensional images, and their locations were verified on the axial, midsagittal, and coronal slices. The Pearson correlation analysis was performed to evaluate the correlation between chin deviation and difference between the measurements of distances in paired craniofacial structures. Statistical analysis was performed at a significance level of 5%. RESULTS: In mandible, the degree of chin deviation was correlated with the mandibular length and mandibular body length. Mandibular length and mandibular body length are shorter on the deviated-chin side compared to that on the non-deviated side (mandibular length, r = -0.897, p value < 0.001; mandibular body length, r = -0.318, p value = 0.045). In the upper and middle facial thirds, the degree of chin deviation was correlated with the vertical asymmetry of the glenoid fossa and zygonion. Glenoid fossa and zygonion are superior on the deviated-chin side than on the non-deviated side (glenoid fossa, r = 0.317, p value = 0.046; zygonion, r = 0.357, p value = 0.024). CONCLUSION: Lateral deviation of chin is correlated with upper and middle facial third asymmetry as well as lower facial third asymmetry. As a result, treatment planning in patients with chin deviation should involve a careful evaluation of the asymmetry of the upper and middle facial thirds to ensure complete patient satisfaction.

Modified difficult index adding extremely difficult for fully impacted mandibular third molar extraction.

OBJECTIVES: The aim of this study was to evaluate the validity of the existing classification and difficulty index of impacted mandibular third molars in clinical situations and propose a more practical classification system. MATERIALS AND METHODS: This study included 204 impacted mandibular third molars in 154 patients; panoramic x-ray images were obtained before tooth extraction. Factors including age, sex, and pattern of impaction were investigated. All impacted third molars were classified and scored for spatial relationship (1-5 points), depth (1-4 points), and ramus relationship (1-3 points). All variables were measured twice by the same observer at a minimum interval of one month. Finally, the difficulty index was defined based on the total points scored as slightly difficult (3-4 points), moderately difficult (5-7 points), very difficult (8-10 points), and extremely difficult (11-12 points). RESULTS: The strength of agreement of the total points scored and difficulty index were 0.855 and 0.746, respectively. Most cases were classified as moderately difficult (73.0%). Although only 13 out of 204 cases (6.4%) were classified as extremely difficult, patients classified as extremely difficult were the oldest (P<0.05). CONCLUSION: For difficulty classification, the authors propose one more difficult category beyond the existing three-step difficulty index: the clinician should consider the patient's age in the difficulty index evaluation.

Nasal changes after surgical correction of skeletal Class III malocclusion in Koreans.

OBJECTIVE: To quantify the changes in the nose after bimaxillary surgery to correct skeletal Class III malocclusion and to test the hypothesis that there is no change in the nasal width following bimaxillary surgical correction of skeletal Class III when a nasal cinch is properly used. MATERIALS AND METHODS: Sixty-five adult Korean skeletal Class III patients who had received maxillary advancement/impaction and mandibular set-back surgery in conjunction with an alar base cinch suture were evaluated. The anthropometric variables of the nasal region were measured directly on the soft-tissue surface before and 6 months after surgery. RESULTS: After surgery, the alar width and alar base width had increased significantly (P < .001), while the nasal tip projection decreased (P < .001). The nostril morphology also showed widening (P < .001). There was a trend for females with a narrow alar width presurgically to have a larger amount of nasal widening compared with those with a broader alar width (P < .05). CONCLUSION: There is a high probability of nasal and nostril widening after bimaxillary surgery for skeletal Class III malocclusion in Koreans despite the careful performance of alar cinch suture. Nevertheless, the authors believe that alar cinch suture was positive in limiting the nasal widening to the minimum and would consider routine application during bimaxillary surgery for skeletal Class III especially for female patients with a narrow nose who are susceptible to these changes.

Subcutaneous emphysema related to dental procedures.

OBJECTIVES: The objective of this study was to analyze 11 cases of subcutaneous emphysema associated with dental procedures from a single hospital and discuss approaches for accurate diagnosis and treatment of the condition. MATERIALS AND METHODS: The medical records of 11 patients who were treated for subcutaneous emphysema related to dental procedures between January 2009 and April 2017 were analyzed retrospectively. Patients with subcutaneous emphysema within the facial area or that spread to the neck and beyond, including the facial region, were assigned to two groups and compared in terms of age, sex, and durations of antibiotic use, hospitalization, and follow-up until improvement. The correlation between location of the origin tooth and range of emphysema spread was analyzed. RESULTS: The average durations of antibiotic use during conservative treatment and follow-up until improvement were 8.55 days (standard deviation [SD], 4.46 days) and 1.82 weeks (SD, 1.19 weeks), respectively. There was no intergroup difference in duration of antibiotic use (P=0.329) or follow-up (P=0.931). Subcutaneous emphysema was more common after dental procedures involving the maxilla or posterior region than after those involving the mandible or anterior region. There was no significant difference in air distribution according to location of the air orifice (maxilla, mandible, or both; P=0.106). CONCLUSION: Upon adequate conservative treatment accompanied by prophylactic antibiotic treatment considering the risk of infection, patients showed signs of improvement within a few days or weeks. There was no significant difference in treatment period between patients with subcutaneous emphysema localized to the facial region and those with subcutaneous emphysema spreading to the neck or beyond. These findings need to be confirmed by analysis of additional cases.

Three-dimensional analysis of the anterior loop of the inferior alveolar nerve in relation to the growth pattern of the mandibular functional subunit.

BACKGROUND: The purpose of the present study was to investigate the differences in the position and shape of the anterior loop of the inferior alveolar nerve (ALIAN) in relation to the growth pattern of the mandibular functional subunit. METHODS: The study was conducted on 56 patients among those who had undergone orthognathic surgery at the Gangnam Severance Hospital between January 2010 and December 2015. Preoperative computerized tomography (CT) images were analyzed using the Simplant OMS software (ver.14.0 Materialise Medical, Leuven, Belgium). The anterior and inferior lengths of ALIAN (dAnt and dInf) and each length of the mandibular functional subunits were measured. The relationship between dAnt, dInf, and the growth pattern of the mandibular subunits was analyzed. RESULTS: The length of the anterior portion of ALIAN (dAnt) reached 3.34 ± 1.59 mm in prognathism and 1.00 ± 0.97 mm in retrognathism. The length of the inferior portion of ALIAN (dInf) reached 6.81 ± 1.33 mm in prognathism and 5.56 ± 1.34 mm in retrognathism. The analysis of Pearson's correlation coefficiency on all samples showed that the lengths of functional subunits were positively correlated with the loop depth. The length of the symphysis area in prognathic patients was positively correlated with the anterior loop depth (p = 0.005). CONCLUSIONS: Both the anterior and inferior length of ALIAN are longer in prognathic patients. Especially, it seems to be associated with the growth of the symphysis area.

Dimension of interproximal soft tissue between adjacent implants in two distinctive implant systems.

BACKGROUND: The purpose of this study was to compare the dimension of interproximal soft tissue between adjacent implants in distinctive implant systems. METHODS: This study involved 85 interproximal papillae between two adjacent implants in 50 patients who had implants placed adjacent to each other and who had prosthesis in place for longer than 1 year. The shortest distance between the radiopaque material on the tip of interimplant papilla and the most coronal portion of the interimplant crestal bone was measured (radiographic length of papilla [RL]). The horizontal distance (HD) between the two adjacent implants was measured at the fixture-abutment interface level. Considering the possible effect of interimplant crestal bone resorption on closely implanted sites, HDs were divided into two categories: HD <3 and >or=3 mm. The Mann-Whitney test was performed to find the difference in the dimension of interimplant papilla. RESULTS: In cases of HD <3 mm, RL did not differ statistically in both systems. Also, in cases of HD >3 mm, RL did not show a statistically significant difference in both systems. CONCLUSION: Both systems had similar dimensions of interproximal soft tissue between adjacent implants, irrespective of the horizontal distance of the fixture.

Comparison of volume and position of the temporomandibular joint structures in patients with mandibular asymmetry.

OBJECTIVE: To evaluate the volume and position of the temporomandibular joint structures, specifically the glenoid fossa and the condylar head, in patients with facial asymmetry. STUDY DESIGN: Fifty-six adult patients were divided into two groups-asymmetry group and control group-based on the severity of the mandibular asymmetry, as seen on their orthopantomograms. The volumes and positions of the bilateral temporomandibular joint components were measured by using computed tomography images and a three-dimensional analysis program. Each of the variables was compared between and within the groups. RESULTS: The volumes of the condyle and the glenoid fossa on the side of the smaller condyle were significantly smaller in the asymmetry group (P < .05) than in the control group. The volumetric ratios of the glenoid fossa and the joint space to the condyle were also significantly higher on that side (P < .001). The distance of the uppermost point of the glenoid fossa from the midaxial plane in the smaller condyle was significantly shorter (P < .05) only in the asymmetry group. CONCLUSIONS: When evaluating mandibular asymmetry, the volume of the glenoid fossa and the volume and vertical position of the condylar head need to be considered in addition to length or width of the condylar head.

Effects of Thread Depth in the Neck Area on Peri-Implant Hard and Soft Tissues: An Animal Study.

BACKGROUND: Implants with deep thread depth have been developed for the purpose of increasing total implant surface area. However, effects of implant thread depth remain controversial. The aim of this study is to examine effects of thread depth on peri-implant tissues in terms of bone-implant contact (BIC), bone-implant volume (BIV), and hard and soft tissue dimensions using comprehensive analyses, including microcomputed tomography (micro-CT). METHODS: Five beagle dogs received experimental intramandibular implants 3 months after removal of their premolars and first molars (P2, P3, P4, and M1). Two different types of implants were installed in each animal: deep threaded (DT) and shallow threaded (ST). Resonance frequency testing was performed on the day of implantation as well as 4 and 8 weeks after implantation. Intraoral radiography, micro-CT, and histomorphometry were used to evaluate peri-implant tissues 4 and 8 weeks after implantation. RESULTS: There were no significant differences in resonance frequency test results between the two groups. Although radiographic analysis showed no group differences, micro-CT (P = 0.01) and histomorphometry (P = 0.003) revealed the DT group had significantly lower BIC values than the ST group at 4 weeks. However, by 8 weeks, BIC values of the two groups did not differ significantly. No significant differences in BIV or soft tissue height were observed between the two groups at either time point. CONCLUSION: DT implants showed no benefits over ST implants when inserted in dog mandibles.

Dimension of keratinized mucosa and the interproximal papilla between adjacent implants.

BACKGROUND: The interproximal papilla between two adjacent implants is gaining critical interest in the implant dentistry. The aims of this study were to evaluate the effect of 1) the width of keratinized mucosa, 2) the distance from the base of the contact point to the crestal bone, and 3) the horizontal distance between two implants on the radiographic dimension from the tip of the papilla to the crestal bone between two implants. METHODS: This study involved 72 interproximal papillae between two adjacent implants (interimplant papilla) in 52 patients who had implants placed adjacent to each other and had a prosthesis in place more than 1 year. The shortest distance between the radiopaque material on the tip of the interimplant papilla and most coronal portion of the interimplant crestal bone was measured (the radiographic length of the papilla [RL]). The width of keratinized mucosa from the tip of the papilla was measured (WK). The vertical distance between the base of the contact point and the interimplant crestal bone was measured (CC). The horizontal distance between the two adjacent implants was measured at the fixture-abutment interface level (HD). Multiple regression analysis was performed between WK-RL, CC-RL, and HD-RL. RESULTS: RL had a significant relation with WK between two adjacent implants (P = 0.001). However, RL was not related with other variables, such as CC and HD (CC, P = 0.641; HD, P = 0.901). CONCLUSION: The results of this study suggest that the width of keratinized mucosa between two adjacent implants might be related to the dimension of the interproximal papilla between two adjacent implants.

Non-invasive method to measure the length of soft tissue from the top of the papilla to the crestal bone.

BACKGROUND: In order to verify the results of interdental papilla regeneration, various methods of measuring the length of the papilla have been introduced. Invasive methods, such as bone probing under local anesthesia, might cause discomfort to the patients and possibly damage the delicate gingival unit. The purpose of the present study was to validate a method of measuring the length of the interdental papilla non-invasively, using radiopaque material and a periapical radiograph. METHODS: This study involved 142 interproximal papillae in 40 patients with chronic periodontitis. The distance between the radiopaque material and most coronal portion of the crestal bone was measured (radiographic length of papilla, RL). Bone probing at the interdental papilla was performed after local anesthesia (bone probing length, BPL). After flap elevation, the actual length of the papilla was measured (actual length of papilla, AL). A correlation analysis was performed between AL-RL and AL-BPL using Pearson's correlation coefficients. RESULTS: The correlation between AL-RL and AL-BPL was 0.903 and 0.931, respectively, both of which showed significance at the 0.01 level. CONCLUSION: The results of this study suggest that the noninvasive method using a radiopaque material and periapical radiograph could be utilized to measure the length of the interdental papilla.