periodontal disease is one of the most common diseases distributed worldwide which leads to formation of osseous defects of the dentitions . in the field of periodontal regeneration , various membranes have been used in the periodontal osseous defects with the principle of guided tissue regeneration . the outcome of these regenerative methods can be assessed by the four different methods , i.e. , histology , probing , radiographs , and direct measurement of bone . histology determines the extent of new attachment which is the standard method to evaluate these regenerative technologies . although this method provides the evidence of new attachment , this seems to be unrealistic evaluating method for clinical studies of regenerative techniques due to the associated inherent problems such as biopsy and sacrifice of teeth . radiographs or direct measurement of bone are the suitable methods in clinical studies to see the bone level . angulation , brightness and contrast , exposure , processing of radiograph , and ability to interpret the film are the controlling factors in assessment of radiographs that limit the use of radiographs in assessing the periodontal regeneration . periodontal probing records the pocket depth and clinical attachment level . depth of probe at the base of pocket was influenced by probing force , inflammation , angulation , probe diameter , and anatomy of tooth . therefore , periodontal probing is always associated with some error which is greater in furcation area . direct measurement of the bone includes the surgical reentry and transgingival probing ( bone sounding ) . surgical reentry is the gold standard method , but it is an invasive , time - consuming procedure and it interrupts the healing process . transgingival probing is the procedure in which tip of the probe makes direct contact with the bone when the probe is forced under local anesthesia through the gingiva . in 1976 have reported that transgingival probing reflects the similar distance as measured after surgical reentry of the alveolar crest at buccal surfaces of the jaw . he proved that transgingival probing is an accurate method to measure the alveolar bone level ( r = 0.975 ) and was not affected by some local factors such as inflammation , location of the site on the tooth surface , and tooth type . used the transgingival probing in furcation defects to evaluate the osseous topography and found that it significantly improves the diagnostic accuracy of furcation defects and reduced the percent and degree of underestimation in all furcation types . the present study was designed with the aims to establish transgingival probing as an evaluating method in the clinical studies of periodontal regenerative techniques and to compare the effectiveness of transgingival probing to the surgical entry . the hypotheses were that the efficacy of two study groups , i.e. , transgingival probing and surgical reentry , is approximately same . ten systemically healthy persons between the age of 20 and 50 years with moderate to severe chronic periodontitis participated in this study . the inclusion criteria were class ii buccal furcation defects in maxillary and/or mandibular first molars having probing depth > 5 mm after phase 1 therapy and no history of systemic disease . the exclusion criteria were unacceptable oral hygiene during the phase 1 therapy , history of allergy , habit of smoking and pan chewing , pregnant or lactating mothers . sample size was calculated with the formula : where p = 0.05 , d = 0.10 ( absolute error ) ,  = 0.05 at two - tailed test , n = 18 cases . a total of twenty samples in ten patients were included and equally divided into two study groups . a general assessment of persons was made through their history taking , physical examination , periodontal examination , and routine investigations . all persons received phase i therapy which includes full mouth scaling and root planing manually and by ultrasonic instruments . a minimum of two visits were utilized to complete initial therapy , with oral hygiene education , motivation , reinforcement , and occlusal adjustments done when indicated . approximately 13 months following the phase 1 therapy , all persons underwent a reevaluation examination to assess periodontal changes . clinical parameters such as vertical probing depth ( vpd ) , horizontal probing depth ( hpd ) of furcation defects , and defect fill ( df ) were evaluated . the periodontal probe was positioned in the midfacial region of the tooth and was inserted into the periodontal pocket parallel to the long axis of the tooth surface . cementoenamel junction ( cej ) was used as fixed point for measuring the clinical parameters in the present study . measurements during initial surgery were taken with and without opening the flap , following local anesthesia according to the method used by mealey et al . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to the opening of the furcation ( f ) was recorded . after that , the probe was progressed further apically up to the alveolar bone , and the distance from the cej to the vertical depth of probing ( vd ) was measured . vpd of furcation defects = ( cej - vd )  ( cej - f ) . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to opening of the furcation was recorded . after that , the probe was progressed further apically up to the alveolar bone in a horizontal direction , and the distance from the cej to the horizontal depth of probing ( hd ) was measured . hpd of furcation defects = ( cej - hd )  ( cej - f ) . the gain of the bone in the vertical and horizontal directions was also measured after 6 months . df = ( cej - vd / hd during initial surgery )  ( cej - vd / hd after 6 months ) . person perception of discomfort / pain experienced without opening the flap and after opening the flap and person satisfaction regarding treatments was also evaluated . one to 3 months after evaluation of phase 1 therapy , the persons were subjected to surgical procedure . all patients were operated under local anesthesia with a solution of 2% lignocaine with 1:80,000 adrenaline . anesthesia was administered by either nerve block or local filtration to adequately anesthetize the surgical site . after anesthesia , transgingival probing was done and measurements were recorded before raising the flap [ figures 1 and 2 ] . after that , conventional flap with only crevicular incision on the facial and lingual side was reflected . after reflection of the flap , debridement of granulation tissue and root surface deposits were accomplished manually and ultrasonic instrumentation . type 1 collagen membrane ( healiguide - advanced biotech product ) was used in the study . the vertical depth of furcation defects during transgingival probing the horizontal depth of furcation defects during transgingival probing the vertical depth of furcation defects after opening the flap the horizontal depth of furcation defects after opening the flap amoxicillin 500 mg and metronidazole 400 mg three times and diclofenac 50 mg twice in a day were prescribed for 5 days . routine postsurgical instructions were given and subjects were recalled after 1 week for checkup and removal of sutures and periodontal dressing . thereafter , postoperative appointments were scheduled at 7 day , 14 day , 1 month , 2 month , 4 month , and 6 month for evaluation of healing of tissues and oral hygiene . at the 2 and 4 month visit , a professional prophylaxis was performed . at the 6 month appointment , all furcation sites were again examined at two separate time points as during initial surgery . all measurements were recorded by single examiner in the same manner as previously prescribed . after collecting and editing , data were entered into the ms excel software and transferred to spss 16.0 version ( spss 16.0 version which is manufactured by ibm corporation , new york , united states ) for analysis . the mean measurements of clinical parameters were compared by two - tailed paired t - test at 5% level of significance . a general assessment of persons was made through their history taking , physical examination , periodontal examination , and routine investigations . all persons received phase i therapy which includes full mouth scaling and root planing manually and by ultrasonic instruments . a minimum of two visits were utilized to complete initial therapy , with oral hygiene education , motivation , reinforcement , and occlusal adjustments done when indicated . approximately 13 months following the phase 1 therapy , all persons underwent a reevaluation examination to assess periodontal changes . clinical parameters such as vertical probing depth ( vpd ) , horizontal probing depth ( hpd ) of furcation defects , and defect fill ( df ) were evaluated . the periodontal probe was positioned in the midfacial region of the tooth and was inserted into the periodontal pocket parallel to the long axis of the tooth surface . cementoenamel junction ( cej ) was used as fixed point for measuring the clinical parameters in the present study . measurements during initial surgery were taken with and without opening the flap , following local anesthesia according to the method used by mealey et al . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to the opening of the furcation ( f ) was recorded . after that , the probe was progressed further apically up to the alveolar bone , and the distance from the cej to the vertical depth of probing ( vd ) was measured . vpd of furcation defects = ( cej - vd )  ( cej - f ) . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to opening of the furcation was recorded . after that , the probe was progressed further apically up to the alveolar bone in a horizontal direction , and the distance from the cej to the horizontal depth of probing ( hd ) was measured . hpd of furcation defects = ( cej - hd )  ( cej - f ) . the gain of the bone in the vertical and horizontal directions was also measured after 6 months . df = ( cej - vd / hd during initial surgery )  ( cej - vd / hd after 6 months ) . person perception of discomfort / pain experienced without opening the flap and after opening the flap and person satisfaction regarding treatments was also evaluated . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to the opening of the furcation ( f ) was recorded . after that , the probe was progressed further apically up to the alveolar bone , and the distance from the cej to the vertical depth of probing ( vd ) was measured . vpd of furcation defects = ( cej - vd )  ( cej - f ) . the probe was inserted into the periodontal pocket to locate the initial fluting of the furcation , and the measurement from the cej to opening of the furcation was recorded . after that , the probe was progressed further apically up to the alveolar bone in a horizontal direction , and the distance from the cej to the horizontal depth of probing ( hd ) was measured . hpd of furcation defects = ( cej - hd )  ( cej - f ) . the gain of the bone in the vertical and horizontal directions was also measured after 6 months . df = ( cej - vd / hd during initial surgery )  ( cej - vd / hd after 6 months ) . person perception of discomfort / pain experienced without opening the flap and after opening the flap and person satisfaction regarding treatments was also evaluated . one to 3 months after evaluation of phase 1 therapy , the persons were subjected to surgical procedure . all patients were operated under local anesthesia with a solution of 2% lignocaine with 1:80,000 adrenaline . anesthesia was administered by either nerve block or local filtration to adequately anesthetize the surgical site . after anesthesia , transgingival probing was done and measurements were recorded before raising the flap [ figures 1 and 2 ] . after that , conventional flap with only crevicular incision on the facial and lingual side was reflected . after reflection of the flap , debridement of granulation tissue and root surface deposits were accomplished manually and ultrasonic instrumentation . type 1 collagen membrane ( healiguide - advanced biotech product ) was used in the study . the vertical depth of furcation defects during transgingival probing the horizontal depth of furcation defects during transgingival probing the vertical depth of furcation defects after opening the flap the horizontal depth of furcation defects after opening the flap amoxicillin 500 mg and metronidazole 400 mg three times and diclofenac 50 mg twice in a day were prescribed for 5 days . routine postsurgical instructions were given and subjects were recalled after 1 week for checkup and removal of sutures and periodontal dressing . thereafter , postoperative appointments were scheduled at 7 day , 14 day , 1 month , 2 month , 4 month , and 6 month for evaluation of healing of tissues and oral hygiene . at the 6 month appointment , all furcation sites were again examined at two separate time points as during initial surgery . after collecting and editing , data were entered into the ms excel software and transferred to spss 16.0 version ( spss 16.0 version which is manufactured by ibm corporation , new york , united states ) for analysis . the mean measurements of clinical parameters were compared by two - tailed paired t - test at 5% level of significance . in the present study , all persons returned at scheduled recall appointments , i.e. , 7 day , 14 day , 1 month , 2 month , 4 month , and 6 month for evaluation of healing of tissues and oral hygiene . no postoperative complications such as redness , pain , allergy , abscess , or swelling was felt by the persons throughout the study period . during the probing after opening the flap , persons had mild pain or discomfort as compared to transgingival probing which is generally associated with surgical procedure . it was observed that few persons were reluctant to go for second surgery because they found it as an unnecessary procedure . the transgingival probing method was appreciated by the persons it is easy , simple and does not involve the surgical procedure . the time required for measuring the clinical parameters was more in case of surgical sounding . evaluation of clinical parameters through surgical re - entry to see the outcomes of regenerative surgeries was also somewhat slight costly as the surgical procedure needs surgical items . mean vpd was 4.00  0.94 mm and 4.20  0.03 mm recorded during transgingival probing and after opening the flap , respectively , at the time of initial surgery . after 6 months , mean vpd was 1.30  0.95 mm and 1.40  1.17 mm measured during transgingival probing and after opening the flap , respectively . at both time points , the difference between the measurements of vpd taken during transgingival probing and after opening the flap was not statistically significant . mean vertical df was 3.00  0.82 mm and 2.80  0.79 mm during transgingival probing and after opening the flap . vertical probing depth of furcation defects the details of the recorded measurements of hd defects are mentioned in table 2 . mean hpd was 4.10  1.10 mm and 4.30  0.48 mm measured during transgingival probing and after opening the flap , respectively , at the time of initial surgery . after 6 months , mean hpd was 2.00  0.67 mm and 1.70  0.48 mm measured during transgingival probing and after opening the flap , respectively . the difference between the measurements of hpd taken during transgingival probing and after opening the flap was not statistically significant during initial surgery as well as after 6 months surgery . mean horizontal df was 2.40  0.70 mm and 2.60  0.51 mm during transgingival probing and after opening the flap . none of them experienced any postoperative complication , but persons experienced slight discomfort or pain during opening the flap as compared to transgingival probing . the transgingival probing method was also appreciated by the patients as it is easy , simple and does not involve the surgical procedure . in the present study , the difference between the measurements of vpd and hpd taken during transgingival probing and after opening the flap was lying in the range of 0.100.30 mm at the time of initial surgery and at 6 months after surgery that was not statistically significant with each other [ tables 1 and 2 ] . . and ursell . renvert et al . reported the mean difference of 0.3 mm , whereas ursell reported the 0.12 mm between the transgingival probing and surgical bone level . reported the 0.39 and 0.54 mm mean difference in vertical and horizontal direction , respectively . mean horizontal df and vertical df during transgingival probing and after opening the flap was 2.40 and 2.60 mm and 3.00 and 2.80 mm , respectively . the results of the present study showed that measurements recorded during transgingival probing and after opening the flap does not influence the required outcome of regenerative therapies , i.e. , df that was also not statistically significant difference from surgical reentry . these results are in accordance with the previous studies in which transgingival probing has also been used in regenerative surgeries and found that bone probing measurements have a high correlation with the surgical reentry measurements and may be a reliable method to evaluate the regenerated bone level in regenerative therapy . in another study in infrabony defects , the bone probing method was compared with the histometric bone level after periodontal regenerative surgeries and found the difference of 0.14 between the bone probing depth and the histometric bone level measurements and coefficient of correlation was 0.90 . underestimation is much more common in probing depth without anesthesia that is affected by probing force , probe direction , probe tip position , inflammatory condition of the periodontal pocket , particularly in furcation area due to external and internal anatomy of the furcation region and presence of soft tissue over the furcal region . to minimize the underestimation , probing after anesthesia , i.e. , transgingival probing , improves the diagnostic accuracy of furcation defects and reduces the percent and degree of underestimation in all furcation types . it has been proved that transgingival probing is a reliable method to measure the alveolar bone level and was not affected by some local factors such as inflammation , location of the site on the tooth surface , and tooth type . although transgingival probing accurately measures the defect sites , the findings are also mild underestimated due to the presence of factors such as external and internal anatomy of the furcation region and presence of soft tissue over the furcal region therefore , transgingival probing can replace the surgical reentry in regenerative therapies as a clinical diagnostic tool for measuring the df . the results of the study might be influenced in positive or negative direction through many variables such as probing force by the examiner , anatomy of the osseous defects , consistency of the bone formed after regenerative therapy , and sample size . to limit the biases related to examiner , all measurements were taken by single examiner . anatomy of the osseous defects and consistency of the bone formed after regenerative therapy difficult to optimize during transgingival probing in comparison to after opening the flap . sample size depended on the availability of persons fulfilling the eligibility criteria and 6 months after surgical reentry period . within the limitations of the study , the results of the present study suggest that transgingival probing can be used as evaluating parameters to see the outcome of regenerative surgeries and the surgical reentry procedure may be avoided because it is a second surgical procedure , time - consuming and interrupts the healing process .
background : the objectives of the present study were to establish transgingival probing as an evaluating method in the clinical studies of periodontal regenerative techniques and to compare the effectiveness of transgingival probing to the surgical entry.materials and methods : ten systemically healthy persons ( 2050 years ) with moderate to severe chronic periodontitis participated in this study . 
 these cases were recruited into the study only when they fulfilled the eligibility criteria . 
 vertical probing depth ( vpd ) and horizontal probing depth ( hpd ) of furcation defects were measured with and without opening the flap , following local anesthesia during initial surgery and at 6 months after collagen membrane placement . 
 the defect fill ( df ) was also noted . 
 the mean measurements of clinical parameters were compared by two - tailed paired t - test at 5% level of significance.results:the difference between the measurements of vpd and hpd taken during transgingival probing and after opening the flap was lie in the range of 0.100.30 mm at the time of initial surgery and 6 months after surgery that was not statistically significant . 
 persons experienced slight discomfort or pain during opening the flap as compared to transgingival probing , and this method was also appreciated by the patients as it is easy , simple and does not involve the surgical procedure.conclusion:the results of the study suggest that measurements recorded during transgingival probing and after opening the flap do not influence the required outcome of regenerative therapies , i.e. , df that was not statistically significant difference from surgical reentry . 
 therefore , it was concluded that transgingival probing could be used as evaluating parameters to see the outcome of regenerative surgeries and the surgical reentry procedure may be avoided because it is a second surgical procedure , time - consuming and interrupts the healing process .